diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9bcea19..dceb5ce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.7.0 (unreleased)
+
+- Added `intvec` type
+
 ## 0.6.2 (2024-03-18)
 
 - Reduced lock contention with parallel HNSW index builds
diff --git a/Makefile b/Makefile
index d5f61ff..15645d5 100644
--- a/Makefile
+++ b/Makefile
@@ -3,8 +3,8 @@ EXTVERSION = 0.6.2
 
 MODULE_big = vector
 DATA = $(wildcard sql/*--*.sql)
-OBJS = src/hnsw.o src/hnswbuild.o src/hnswinsert.o src/hnswscan.o src/hnswutils.o src/hnswvacuum.o src/ivfbuild.o src/ivfflat.o src/ivfinsert.o src/ivfkmeans.o src/ivfscan.o src/ivfutils.o src/ivfvacuum.o src/vector.o
-HEADERS = src/vector.h
+OBJS = src/hnsw.o src/hnswbuild.o src/hnswinsert.o src/hnswscan.o src/hnswutils.o src/hnswvacuum.o src/intvec.o src/ivfbuild.o src/ivfflat.o src/ivfinsert.o src/ivfkmeans.o src/ivfscan.o src/ivfutils.o src/ivfvacuum.o src/vector.o
+HEADERS = src/intvec.h src/vector.h
 
 TESTS = $(wildcard test/sql/*.sql)
 REGRESS = $(patsubst test/sql/%.sql,%,$(TESTS))
diff --git a/Makefile.win b/Makefile.win
index 1bb193e..d8e7fc1 100644
--- a/Makefile.win
+++ b/Makefile.win
@@ -1,8 +1,8 @@
 EXTENSION = vector
 EXTVERSION = 0.6.2
 
-OBJS = src\hnsw.obj src\hnswbuild.obj src\hnswinsert.obj src\hnswscan.obj src\hnswutils.obj src\hnswvacuum.obj src\ivfbuild.obj src\ivfflat.obj src\ivfinsert.obj src\ivfkmeans.obj src\ivfscan.obj src\ivfutils.obj src\ivfvacuum.obj src\vector.obj
-HEADERS = src\vector.h
+OBJS = src\hnsw.obj src\hnswbuild.obj src\hnswinsert.obj src\hnswscan.obj src\hnswutils.obj src\hnswvacuum.obj src\intvec.obj src\ivfbuild.obj src\ivfflat.obj src\ivfinsert.obj src\ivfkmeans.obj src\ivfscan.obj src\ivfutils.obj src\ivfvacuum.obj src\vector.obj
+HEADERS = src\intvec.h src\vector.h
 
 REGRESS = btree cast copy functions input ivfflat_cosine ivfflat_ip ivfflat_l2 ivfflat_options ivfflat_unlogged
 REGRESS_OPTS = --inputdir=test --load-extension=$(EXTENSION)
diff --git a/README.md b/README.md
index f9849c8..4a5906f 100644
--- a/README.md
+++ b/README.md
@@ -732,6 +732,27 @@ Function | Description | Added
 avg(vector) → vector | average |
 sum(vector) → vector | sum | 0.5.0
 
+### Intvec Type
+
+Each int vector takes `dimensions + 8` bytes of storage. Each element is a single byte signed integer. Int vectors can have up to 16,000 dimensions.
+
+### Intvec Operators
+
+Operator | Description | Added
+--- | --- | ---
+<-> | Euclidean distance | 0.7.0
+<#> | negative inner product | 0.7.0
+<=> | cosine distance | 0.7.0
+
+### Intvec Functions
+
+Function | Description | Added
+--- | --- | ---
+cosine_distance(intvec, intvec) → double precision | cosine distance | 0.7.0
+inner_product(intvec, intvec) → double precision | inner product | 0.7.0
+l2_distance(intvec, intvec) → double precision | Euclidean distance | 0.7.0
+l1_distance(intvec, intvec) → double precision | taxicab distance | 0.7.0
+
 ## Installation Notes - Linux and Mac
 
 ### Postgres Location
diff --git a/sql/vector--0.6.2--0.7.0.sql b/sql/vector--0.6.2--0.7.0.sql
new file mode 100644
index 0000000..3b8e346
--- /dev/null
+++ b/sql/vector--0.6.2--0.7.0.sql
@@ -0,0 +1,88 @@
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "ALTER EXTENSION vector UPDATE TO '0.7.0'" to load this file. \quit
+
+CREATE TYPE intvec;
+
+CREATE FUNCTION intvec_in(cstring, oid, integer) RETURNS intvec
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_out(intvec) RETURNS cstring
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_typmod_in(cstring[]) RETURNS integer
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_recv(internal, oid, integer) RETURNS intvec
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_send(intvec) RETURNS bytea
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE TYPE intvec (
+	INPUT     = intvec_in,
+	OUTPUT    = intvec_out,
+	TYPMOD_IN = intvec_typmod_in,
+	RECEIVE   = intvec_recv,
+	SEND      = intvec_send,
+	STORAGE   = external
+);
+
+CREATE FUNCTION l2_distance(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME', 'intvec_l2_distance' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION inner_product(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME', 'intvec_inner_product' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION cosine_distance(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME', 'intvec_cosine_distance' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION l1_distance(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME', 'intvec_l1_distance' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_l2_squared_distance(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_negative_inner_product(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec(intvec, integer, boolean) RETURNS intvec
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION array_to_intvec(integer[], integer, boolean) RETURNS intvec
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE CAST (intvec AS intvec)
+	WITH FUNCTION intvec(intvec, integer, boolean) AS IMPLICIT;
+
+CREATE CAST (integer[] AS intvec)
+	WITH FUNCTION array_to_intvec(integer[], integer, boolean) AS ASSIGNMENT;
+
+CREATE OPERATOR <-> (
+	LEFTARG = intvec, RIGHTARG = intvec, PROCEDURE = l2_distance,
+	COMMUTATOR = '<->'
+);
+
+CREATE OPERATOR <#> (
+	LEFTARG = intvec, RIGHTARG = intvec, PROCEDURE = intvec_negative_inner_product,
+	COMMUTATOR = '<#>'
+);
+
+CREATE OPERATOR <=> (
+	LEFTARG = intvec, RIGHTARG = intvec, PROCEDURE = cosine_distance,
+	COMMUTATOR = '<=>'
+);
+
+CREATE OPERATOR CLASS intvec_l2_ops
+	FOR TYPE intvec USING hnsw AS
+	OPERATOR 1 <-> (intvec, intvec) FOR ORDER BY float_ops,
+	FUNCTION 1 intvec_l2_squared_distance(intvec, intvec);
+
+CREATE OPERATOR CLASS intvec_ip_ops
+	FOR TYPE intvec USING hnsw AS
+	OPERATOR 1 <#> (intvec, intvec) FOR ORDER BY float_ops,
+	FUNCTION 1 intvec_negative_inner_product(intvec, intvec);
+
+CREATE OPERATOR CLASS intvec_cosine_ops
+	FOR TYPE intvec USING hnsw AS
+	OPERATOR 1 <=> (intvec, intvec) FOR ORDER BY float_ops,
+	FUNCTION 1 cosine_distance(intvec, intvec);
diff --git a/sql/vector.sql b/sql/vector.sql
index 141e83c..05d97a2 100644
--- a/sql/vector.sql
+++ b/sql/vector.sql
@@ -287,3 +287,103 @@ CREATE OPERATOR CLASS vector_cosine_ops
 	OPERATOR 1 <=> (vector, vector) FOR ORDER BY float_ops,
 	FUNCTION 1 vector_negative_inner_product(vector, vector),
 	FUNCTION 2 vector_norm(vector);
+
+-- intvec type
+
+CREATE TYPE intvec;
+
+CREATE FUNCTION intvec_in(cstring, oid, integer) RETURNS intvec
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_out(intvec) RETURNS cstring
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_typmod_in(cstring[]) RETURNS integer
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_recv(internal, oid, integer) RETURNS intvec
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_send(intvec) RETURNS bytea
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE TYPE intvec (
+	INPUT     = intvec_in,
+	OUTPUT    = intvec_out,
+	TYPMOD_IN = intvec_typmod_in,
+	RECEIVE   = intvec_recv,
+	SEND      = intvec_send,
+	STORAGE   = external
+);
+
+-- intvec functions
+
+CREATE FUNCTION l2_distance(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME', 'intvec_l2_distance' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION inner_product(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME', 'intvec_inner_product' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION cosine_distance(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME', 'intvec_cosine_distance' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION l1_distance(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME', 'intvec_l1_distance' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+-- intvec private functions
+
+CREATE FUNCTION intvec_l2_squared_distance(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION intvec_negative_inner_product(intvec, intvec) RETURNS float8
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+-- intvec cast functions
+
+CREATE FUNCTION intvec(intvec, integer, boolean) RETURNS intvec
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+CREATE FUNCTION array_to_intvec(integer[], integer, boolean) RETURNS intvec
+	AS 'MODULE_PATHNAME' LANGUAGE C IMMUTABLE STRICT PARALLEL SAFE;
+
+-- intvec casts
+
+CREATE CAST (intvec AS intvec)
+	WITH FUNCTION intvec(intvec, integer, boolean) AS IMPLICIT;
+
+CREATE CAST (integer[] AS intvec)
+	WITH FUNCTION array_to_intvec(integer[], integer, boolean) AS ASSIGNMENT;
+
+-- intvec operators
+
+CREATE OPERATOR <-> (
+	LEFTARG = intvec, RIGHTARG = intvec, PROCEDURE = l2_distance,
+	COMMUTATOR = '<->'
+);
+
+CREATE OPERATOR <#> (
+	LEFTARG = intvec, RIGHTARG = intvec, PROCEDURE = intvec_negative_inner_product,
+	COMMUTATOR = '<#>'
+);
+
+CREATE OPERATOR <=> (
+	LEFTARG = intvec, RIGHTARG = intvec, PROCEDURE = cosine_distance,
+	COMMUTATOR = '<=>'
+);
+
+-- intvec opclasses
+
+CREATE OPERATOR CLASS intvec_l2_ops
+	FOR TYPE intvec USING hnsw AS
+	OPERATOR 1 <-> (intvec, intvec) FOR ORDER BY float_ops,
+	FUNCTION 1 intvec_l2_squared_distance(intvec, intvec);
+
+CREATE OPERATOR CLASS intvec_ip_ops
+	FOR TYPE intvec USING hnsw AS
+	OPERATOR 1 <#> (intvec, intvec) FOR ORDER BY float_ops,
+	FUNCTION 1 intvec_negative_inner_product(intvec, intvec);
+
+CREATE OPERATOR CLASS intvec_cosine_ops
+	FOR TYPE intvec USING hnsw AS
+	OPERATOR 1 <=> (intvec, intvec) FOR ORDER BY float_ops,
+	FUNCTION 1 cosine_distance(intvec, intvec);
diff --git a/src/hnsw.h b/src/hnsw.h
index 901f22b..207ded6 100644
--- a/src/hnsw.h
+++ b/src/hnsw.h
@@ -57,7 +57,8 @@
 
 typedef enum HnswType
 {
-	HNSW_TYPE_VECTOR
+	HNSW_TYPE_VECTOR,
+	HNSW_TYPE_INTVEC
 }			HnswType;
 
 /* Build phases */
diff --git a/src/hnswbuild.c b/src/hnswbuild.c
index cd7150d..1806d94 100644
--- a/src/hnswbuild.c
+++ b/src/hnswbuild.c
@@ -683,6 +683,9 @@ InitBuildState(HnswBuildState * buildstate, Relation heap, Relation index, Index
 	buildstate->efConstruction = HnswGetEfConstruction(index);
 	buildstate->dimensions = TupleDescAttr(index->rd_att, 0)->atttypmod;
 
+	if (buildstate->type == HNSW_TYPE_INTVEC)
+		maxDimensions *= 4;
+
 	/* Require column to have dimensions to be indexed */
 	if (buildstate->dimensions < 0)
 		elog(ERROR, "column does not have dimensions");
diff --git a/src/hnswutils.c b/src/hnswutils.c
index 0c828ae..0104c81 100644
--- a/src/hnswutils.c
+++ b/src/hnswutils.c
@@ -1,14 +1,17 @@
 #include "postgres.h"
 
+#include <float.h>
 #include <math.h>
 
 #include "access/generic_xlog.h"
+#include "catalog/pg_type.h"
 #include "hnsw.h"
 #include "lib/pairingheap.h"
 #include "storage/bufmgr.h"
 #include "utils/datum.h"
 #include "utils/memdebug.h"
 #include "utils/rel.h"
+#include "utils/syscache.h"
 #include "vector.h"
 
 #if PG_VERSION_NUM >= 130000
@@ -155,7 +158,24 @@ HnswOptionalProcInfo(Relation index, uint16 procnum)
 HnswType
 HnswGetType(Relation index)
 {
-	return HNSW_TYPE_VECTOR;
+	Oid			typeOid = TupleDescAttr(index->rd_att, 0)->atttypid;
+	HeapTuple	tuple;
+	Form_pg_type type;
+	int			result;
+
+	tuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typeOid));
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "cache lookup failed for type %u", typeOid);
+
+	type = (Form_pg_type) GETSTRUCT(tuple);
+	if (strcmp(NameStr(type->typname), "intvec") == 0)
+		result = HNSW_TYPE_INTVEC;
+	else
+		result = HNSW_TYPE_VECTOR;
+
+	ReleaseSysCache(tuple);
+
+	return result;
 }
 
 /*
@@ -592,7 +612,14 @@ HnswLoadElement(HnswElement element, float *distance, Datum *q, Relation index,
 		if (DatumGetPointer(*q) == NULL)
 			*distance = 0;
 		else
+		{
 			*distance = (float) DatumGetFloat8(FunctionCall2Coll(procinfo, collation, *q, PointerGetDatum(&etup->data)));
+
+			/* Needed for intvec cosine distance */
+			/* TODO Improve */
+			if (isnan(*distance))
+				*distance = FLT_MAX;
+		}
 	}
 
 	UnlockReleaseBuffer(buf);
diff --git a/src/intvec.c b/src/intvec.c
new file mode 100644
index 0000000..164b931
--- /dev/null
+++ b/src/intvec.c
@@ -0,0 +1,586 @@
+#include "postgres.h"
+
+#include <limits.h>
+#include <math.h>
+
+#include "catalog/pg_type.h"
+#include "fmgr.h"
+#include "intvec.h"
+#include "lib/stringinfo.h"
+#include "libpq/pqformat.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+
+/*
+ * Ensure same dimensions
+ */
+static inline void
+CheckDims(IntVector * a, IntVector * b)
+{
+	if (a->dim != b->dim)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_EXCEPTION),
+				 errmsg("different intvec dimensions %d and %d", a->dim, b->dim)));
+}
+
+/*
+ * Ensure expected dimensions
+ */
+static inline void
+CheckExpectedDim(int32 typmod, int dim)
+{
+	if (typmod != -1 && typmod != dim)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_EXCEPTION),
+				 errmsg("expected %d dimensions, not %d", typmod, dim)));
+}
+
+/*
+ * Ensure valid dimensions
+ */
+static inline void
+CheckDim(int dim)
+{
+	if (dim < 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_EXCEPTION),
+				 errmsg("intvec must have at least 1 dimension")));
+
+	if (dim > INTVEC_MAX_DIM)
+		ereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("intvec cannot have more than %d dimensions", INTVEC_MAX_DIM)));
+}
+
+/*
+ * Ensure element in range
+ */
+static inline void
+CheckElement(long value)
+{
+	if (value < SCHAR_MIN || value > SCHAR_MAX)
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("value \"%ld\" is out of range for type intvec", value)));
+}
+
+/*
+ * Allocate and initialize a new int vector
+ */
+IntVector *
+InitIntVector(int dim)
+{
+	IntVector  *result;
+	int			size;
+
+	size = INTVEC_SIZE(dim);
+	result = (IntVector *) palloc0(size);
+	SET_VARSIZE(result, size);
+	result->dim = dim;
+
+	return result;
+}
+
+/*
+ * Check for whitespace, since array_isspace() is static
+ */
+static inline bool
+intvec_isspace(char ch)
+{
+	if (ch == ' ' ||
+		ch == '\t' ||
+		ch == '\n' ||
+		ch == '\r' ||
+		ch == '\v' ||
+		ch == '\f')
+		return true;
+	return false;
+}
+
+/*
+ * Convert textual representation to internal representation
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_in);
+Datum
+intvec_in(PG_FUNCTION_ARGS)
+{
+	char	   *lit = PG_GETARG_CSTRING(0);
+	int32		typmod = PG_GETARG_INT32(2);
+	int8		x[INTVEC_MAX_DIM];
+	int			dim = 0;
+	char	   *pt;
+	char	   *stringEnd;
+	IntVector  *result;
+	char	   *litcopy = pstrdup(lit);
+	char	   *str = litcopy;
+
+	while (intvec_isspace(*str))
+		str++;
+
+	if (*str != '[')
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+				 errmsg("malformed intvec literal: \"%s\"", lit),
+				 errdetail("Vector contents must start with \"[\".")));
+
+	str++;
+	pt = strtok(str, ",");
+	stringEnd = pt;
+
+	while (pt != NULL && *stringEnd != ']')
+	{
+		long		l;
+
+		if (dim == INTVEC_MAX_DIM)
+			ereport(ERROR,
+					(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+					 errmsg("intvec cannot have more than %d dimensions", INTVEC_MAX_DIM)));
+
+		while (intvec_isspace(*pt))
+			pt++;
+
+		/* Check for empty string like float4in */
+		if (*pt == '\0')
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+					 errmsg("invalid input syntax for type intvec: \"%s\"", lit)));
+
+		/* Use similar logic as int2vectorin */
+		errno = 0;
+		l = strtol(pt, &stringEnd, 10);
+
+		if (stringEnd == pt)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+					 errmsg("invalid input syntax for type intvec: \"%s\"", lit)));
+
+		if (errno == ERANGE || l < SCHAR_MIN || l > SCHAR_MAX)
+			ereport(ERROR,
+					(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+					 errmsg("value \"%s\" is out of range for type intvec", pt)));
+
+		x[dim++] = l;
+
+		while (intvec_isspace(*stringEnd))
+			stringEnd++;
+
+		if (*stringEnd != '\0' && *stringEnd != ']')
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+					 errmsg("invalid input syntax for type intvec: \"%s\"", lit)));
+
+		pt = strtok(NULL, ",");
+	}
+
+	if (stringEnd == NULL || *stringEnd != ']')
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+				 errmsg("malformed intvec literal: \"%s\"", lit),
+				 errdetail("Unexpected end of input.")));
+
+	stringEnd++;
+
+	/* Only whitespace is allowed after the closing brace */
+	while (intvec_isspace(*stringEnd))
+		stringEnd++;
+
+	if (*stringEnd != '\0')
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+				 errmsg("malformed intvec literal: \"%s\"", lit),
+				 errdetail("Junk after closing right brace.")));
+
+	/* Ensure no consecutive delimiters since strtok skips */
+	for (pt = lit + 1; *pt != '\0'; pt++)
+	{
+		if (pt[-1] == ',' && *pt == ',')
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+					 errmsg("malformed intvec literal: \"%s\"", lit)));
+	}
+
+	if (dim < 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_EXCEPTION),
+				 errmsg("intvec must have at least 1 dimension")));
+
+	pfree(litcopy);
+
+	CheckExpectedDim(typmod, dim);
+
+	result = InitIntVector(dim);
+	for (int i = 0; i < dim; i++)
+		result->x[i] = x[i];
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+ * Convert internal representation to textual representation
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_out);
+Datum
+intvec_out(PG_FUNCTION_ARGS)
+{
+	IntVector  *vector = PG_GETARG_INTVEC_P(0);
+	int			dim = vector->dim;
+	char	   *buf;
+	char	   *ptr;
+	int			n;
+
+	/*
+	 * Need:
+	 *
+	 * dim * 4 bytes for elements (-128 to 127)
+	 *
+	 * dim - 1 bytes for separator
+	 *
+	 * 3 bytes for [, ], and \0
+	 */
+	buf = (char *) palloc(5 * dim + 2);
+	ptr = buf;
+
+	*ptr = '[';
+	ptr++;
+	for (int i = 0; i < dim; i++)
+	{
+		if (i > 0)
+		{
+			*ptr = ',';
+			ptr++;
+		}
+
+		n = pg_ltoa(vector->x[i], ptr);
+		ptr += n;
+	}
+	*ptr = ']';
+	ptr++;
+	*ptr = '\0';
+
+	PG_FREE_IF_COPY(vector, 0);
+	PG_RETURN_CSTRING(buf);
+}
+
+/*
+ * Convert type modifier
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_typmod_in);
+Datum
+intvec_typmod_in(PG_FUNCTION_ARGS)
+{
+	ArrayType  *ta = PG_GETARG_ARRAYTYPE_P(0);
+	int32	   *tl;
+	int			n;
+
+	tl = ArrayGetIntegerTypmods(ta, &n);
+
+	if (n != 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("invalid type modifier")));
+
+	if (*tl < 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("dimensions for type intvec must be at least 1")));
+
+	if (*tl > INTVEC_MAX_DIM)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("dimensions for type intvec cannot exceed %d", INTVEC_MAX_DIM)));
+
+	PG_RETURN_INT32(*tl);
+}
+
+/*
+ * Convert external binary representation to internal representation
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_recv);
+Datum
+intvec_recv(PG_FUNCTION_ARGS)
+{
+	StringInfo	buf = (StringInfo) PG_GETARG_POINTER(0);
+	int32		typmod = PG_GETARG_INT32(2);
+	IntVector  *result;
+	int16		dim;
+	int16		unused;
+
+	dim = pq_getmsgint(buf, sizeof(int16));
+	unused = pq_getmsgint(buf, sizeof(int16));
+
+	CheckDim(dim);
+	CheckExpectedDim(typmod, dim);
+
+	if (unused != 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_EXCEPTION),
+				 errmsg("expected unused to be 0, not %d", unused)));
+
+	result = InitIntVector(dim);
+	for (int i = 0; i < dim; i++)
+		result->x[i] = pq_getmsgint(buf, sizeof(int8));
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+ * Convert internal representation to the external binary representation
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_send);
+Datum
+intvec_send(PG_FUNCTION_ARGS)
+{
+	IntVector  *vec = PG_GETARG_INTVEC_P(0);
+	StringInfoData buf;
+
+	pq_begintypsend(&buf);
+	pq_sendint(&buf, vec->dim, sizeof(int16));
+	pq_sendint(&buf, vec->unused, sizeof(int16));
+	for (int i = 0; i < vec->dim; i++)
+		pq_sendint8(&buf, vec->x[i]);
+
+	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
+}
+
+/*
+ * Convert int vector to int vector
+ * This is needed to check the type modifier
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec);
+Datum
+intvec(PG_FUNCTION_ARGS)
+{
+	IntVector  *vec = PG_GETARG_INTVEC_P(0);
+	int32		typmod = PG_GETARG_INT32(1);
+
+	CheckExpectedDim(typmod, vec->dim);
+
+	PG_RETURN_POINTER(vec);
+}
+
+/*
+ * Convert array to intvec vector
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(array_to_intvec);
+Datum
+array_to_intvec(PG_FUNCTION_ARGS)
+{
+	ArrayType  *array = PG_GETARG_ARRAYTYPE_P(0);
+	int32		typmod = PG_GETARG_INT32(1);
+	Vector	   *result;
+	int16		typlen;
+	bool		typbyval;
+	char		typalign;
+	Datum	   *elemsp;
+	int			nelemsp;
+
+	if (ARR_NDIM(array) > 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_EXCEPTION),
+				 errmsg("array must be 1-D")));
+
+	if (ARR_HASNULL(array) && array_contains_nulls(array))
+		ereport(ERROR,
+				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
+				 errmsg("array must not contain nulls")));
+
+	get_typlenbyvalalign(ARR_ELEMTYPE(array), &typlen, &typbyval, &typalign);
+	deconstruct_array(array, ARR_ELEMTYPE(array), typlen, typbyval, typalign, &elemsp, NULL, &nelemsp);
+
+	CheckDim(nelemsp);
+	CheckExpectedDim(typmod, nelemsp);
+
+	result = InitVector(nelemsp);
+
+	if (ARR_ELEMTYPE(array) == INT4OID)
+	{
+		for (int i = 0; i < nelemsp; i++)
+		{
+			long		l = DatumGetInt32(elemsp[i]);
+
+			CheckElement(l);
+
+			result->x[i] = l;
+		}
+	}
+	else
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_EXCEPTION),
+				 errmsg("unsupported array type")));
+	}
+
+	/*
+	 * Free allocation from deconstruct_array. Do not free individual elements
+	 * when pass-by-reference since they point to original array.
+	 */
+	pfree(elemsp);
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+ * Get the L2 distance between int vectors
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_l2_distance);
+Datum
+intvec_l2_distance(PG_FUNCTION_ARGS)
+{
+	IntVector  *a = PG_GETARG_INTVEC_P(0);
+	IntVector  *b = PG_GETARG_INTVEC_P(1);
+	int8	   *ax = a->x;
+	int8	   *bx = b->x;
+	int			distance = 0;
+
+	CheckDims(a, b);
+
+	/* Auto-vectorized */
+	for (int i = 0; i < a->dim; i++)
+	{
+		int			diff = ax[i] - bx[i];
+
+		distance += diff * diff;
+	}
+
+	PG_RETURN_FLOAT8(sqrt((double) distance));
+}
+
+/*
+ * Get the L2 squared distance between int vectors
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_l2_squared_distance);
+Datum
+intvec_l2_squared_distance(PG_FUNCTION_ARGS)
+{
+	IntVector  *a = PG_GETARG_INTVEC_P(0);
+	IntVector  *b = PG_GETARG_INTVEC_P(1);
+	int8	   *ax = a->x;
+	int8	   *bx = b->x;
+	int			distance = 0;
+
+	CheckDims(a, b);
+
+	/* Auto-vectorized */
+	for (int i = 0; i < a->dim; i++)
+	{
+		int			diff = ax[i] - bx[i];
+
+		distance += diff * diff;
+	}
+
+	PG_RETURN_FLOAT8((double) distance);
+}
+
+/*
+ * Get the inner product of two int vectors
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_inner_product);
+Datum
+intvec_inner_product(PG_FUNCTION_ARGS)
+{
+	IntVector  *a = PG_GETARG_INTVEC_P(0);
+	IntVector  *b = PG_GETARG_INTVEC_P(1);
+	int8	   *ax = a->x;
+	int8	   *bx = b->x;
+	int			distance = 0;
+
+	CheckDims(a, b);
+
+	/* Auto-vectorized */
+	for (int i = 0; i < a->dim; i++)
+		distance += ax[i] * bx[i];
+
+	PG_RETURN_FLOAT8((double) distance);
+}
+
+/*
+ * Get the negative inner product of two int vectors
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_negative_inner_product);
+Datum
+intvec_negative_inner_product(PG_FUNCTION_ARGS)
+{
+	IntVector  *a = PG_GETARG_INTVEC_P(0);
+	IntVector  *b = PG_GETARG_INTVEC_P(1);
+	int8	   *ax = a->x;
+	int8	   *bx = b->x;
+	int			distance = 0;
+
+	CheckDims(a, b);
+
+	/* Auto-vectorized */
+	for (int i = 0; i < a->dim; i++)
+		distance += ax[i] * bx[i];
+
+	PG_RETURN_FLOAT8((double) -distance);
+}
+
+/*
+ * Get the cosine distance between two int vectors
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_cosine_distance);
+Datum
+intvec_cosine_distance(PG_FUNCTION_ARGS)
+{
+	IntVector  *a = PG_GETARG_INTVEC_P(0);
+	IntVector  *b = PG_GETARG_INTVEC_P(1);
+	int8	   *ax = a->x;
+	int8	   *bx = b->x;
+	int			distance = 0;
+	int			norma = 0;
+	int			normb = 0;
+	double		similarity;
+
+	CheckDims(a, b);
+
+	/* Auto-vectorized */
+	for (int i = 0; i < a->dim; i++)
+	{
+		int8		axi = ax[i];
+		int8		bxi = bx[i];
+
+		distance += axi * bxi;
+		norma += axi * axi;
+		normb += bxi * bxi;
+	}
+
+	/* Use sqrt(a * b) over sqrt(a) * sqrt(b) */
+	similarity = (double) distance / sqrt((double) norma * (double) normb);
+
+#ifdef _MSC_VER
+	/* /fp:fast may not propagate NaN */
+	if (isnan(similarity))
+		PG_RETURN_FLOAT8(NAN);
+#endif
+
+	/* Keep in range */
+	if (similarity > 1)
+		similarity = 1;
+	else if (similarity < -1)
+		similarity = -1;
+
+	PG_RETURN_FLOAT8(1 - similarity);
+}
+
+/*
+ * Get the L1 distance between two int vectors
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(intvec_l1_distance);
+Datum
+intvec_l1_distance(PG_FUNCTION_ARGS)
+{
+	IntVector  *a = PG_GETARG_INTVEC_P(0);
+	IntVector  *b = PG_GETARG_INTVEC_P(1);
+	int8	   *ax = a->x;
+	int8	   *bx = b->x;
+	int			distance = 0;
+
+	CheckDims(a, b);
+
+	/* Auto-vectorized */
+	for (int i = 0; i < a->dim; i++)
+		distance += abs(ax[i] - bx[i]);
+
+	PG_RETURN_FLOAT8((double) distance);
+}
diff --git a/src/intvec.h b/src/intvec.h
new file mode 100644
index 0000000..cf5f367
--- /dev/null
+++ b/src/intvec.h
@@ -0,0 +1,23 @@
+#ifndef INTVEC_H
+#define INTVEC_H
+
+#include "vector.h"
+
+#define INTVEC_MAX_DIM VECTOR_MAX_DIM
+
+#define INTVEC_SIZE(_dim)		(offsetof(IntVector, x) + sizeof(int8)*(_dim))
+#define DatumGetIntVector(x)	((IntVector *) PG_DETOAST_DATUM(x))
+#define PG_GETARG_INTVEC_P(x)	DatumGetIntVector(PG_GETARG_DATUM(x))
+#define PG_RETURN_INTVEC_P(x)	PG_RETURN_POINTER(x)
+
+typedef struct IntVector
+{
+	int32		vl_len_;		/* varlena header (do not touch directly!) */
+	int16		dim;			/* number of dimensions */
+	int16		unused;
+	int8		x[FLEXIBLE_ARRAY_MEMBER];
+}			IntVector;
+
+IntVector  *InitIntVector(int dim);
+
+#endif
diff --git a/test/expected/copy.out b/test/expected/copy.out
index 36d4620..ce85454 100644
--- a/test/expected/copy.out
+++ b/test/expected/copy.out
@@ -1,15 +1,15 @@
-CREATE TABLE t (val vector(3));
-INSERT INTO t (val) VALUES ('[0,0,0]'), ('[1,2,3]'), ('[1,1,1]'), (NULL);
-CREATE TABLE t2 (val vector(3));
+CREATE TABLE t (val vector(3), val2 intvec(3));
+INSERT INTO t (val, val2) VALUES ('[0,0,0]', '[0,0,0]'), ('[1,2,3]', '[1,2,3]'), ('[1,1,1]', '[1,1,1]'), (NULL, NULL);
+CREATE TABLE t2 (val vector(3), val2 intvec(3));
 \copy t TO 'results/data.bin' WITH (FORMAT binary)
 \copy t2 FROM 'results/data.bin' WITH (FORMAT binary)
 SELECT * FROM t2 ORDER BY val;
-   val   
----------
- [0,0,0]
- [1,1,1]
- [1,2,3]
- 
+   val   |  val2   
+---------+---------
+ [0,0,0] | [0,0,0]
+ [1,1,1] | [1,1,1]
+ [1,2,3] | [1,2,3]
+         | 
 (4 rows)
 
 DROP TABLE t;
diff --git a/test/expected/functions.out b/test/expected/functions.out
index 85d1a2f..12f8f6d 100644
--- a/test/expected/functions.out
+++ b/test/expected/functions.out
@@ -104,105 +104,105 @@ SELECT vector_norm('[3e37,4e37]')::real;
        5e+37
 (1 row)
 
-SELECT l2_distance('[0,0]', '[3,4]');
+SELECT l2_distance('[0,0]'::vector, '[3,4]');
  l2_distance 
 -------------
            5
 (1 row)
 
-SELECT l2_distance('[0,0]', '[0,1]');
+SELECT l2_distance('[0,0]'::vector, '[0,1]');
  l2_distance 
 -------------
            1
 (1 row)
 
-SELECT l2_distance('[1,2]', '[3]');
+SELECT l2_distance('[1,2]'::vector, '[3]');
 ERROR:  different vector dimensions 2 and 1
-SELECT l2_distance('[3e38]', '[-3e38]');
+SELECT l2_distance('[3e38]'::vector, '[-3e38]');
  l2_distance 
 -------------
     Infinity
 (1 row)
 
-SELECT inner_product('[1,2]', '[3,4]');
+SELECT inner_product('[1,2]'::vector, '[3,4]');
  inner_product 
 ---------------
             11
 (1 row)
 
-SELECT inner_product('[1,2]', '[3]');
+SELECT inner_product('[1,2]'::vector, '[3]');
 ERROR:  different vector dimensions 2 and 1
-SELECT inner_product('[3e38]', '[3e38]');
+SELECT inner_product('[3e38]'::vector, '[3e38]');
  inner_product 
 ---------------
       Infinity
 (1 row)
 
-SELECT cosine_distance('[1,2]', '[2,4]');
+SELECT cosine_distance('[1,2]'::vector, '[2,4]');
  cosine_distance 
 -----------------
                0
 (1 row)
 
-SELECT cosine_distance('[1,2]', '[0,0]');
+SELECT cosine_distance('[1,2]'::vector, '[0,0]');
  cosine_distance 
 -----------------
              NaN
 (1 row)
 
-SELECT cosine_distance('[1,1]', '[1,1]');
+SELECT cosine_distance('[1,1]'::vector, '[1,1]');
  cosine_distance 
 -----------------
                0
 (1 row)
 
-SELECT cosine_distance('[1,0]', '[0,2]');
+SELECT cosine_distance('[1,0]'::vector, '[0,2]');
  cosine_distance 
 -----------------
                1
 (1 row)
 
-SELECT cosine_distance('[1,1]', '[-1,-1]');
+SELECT cosine_distance('[1,1]'::vector, '[-1,-1]');
  cosine_distance 
 -----------------
                2
 (1 row)
 
-SELECT cosine_distance('[1,2]', '[3]');
+SELECT cosine_distance('[1,2]'::vector, '[3]');
 ERROR:  different vector dimensions 2 and 1
-SELECT cosine_distance('[1,1]', '[1.1,1.1]');
+SELECT cosine_distance('[1,1]'::vector, '[1.1,1.1]');
  cosine_distance 
 -----------------
                0
 (1 row)
 
-SELECT cosine_distance('[1,1]', '[-1.1,-1.1]');
+SELECT cosine_distance('[1,1]'::vector, '[-1.1,-1.1]');
  cosine_distance 
 -----------------
                2
 (1 row)
 
-SELECT cosine_distance('[3e38]', '[3e38]');
+SELECT cosine_distance('[3e38]'::vector, '[3e38]');
  cosine_distance 
 -----------------
              NaN
 (1 row)
 
-SELECT l1_distance('[0,0]', '[3,4]');
+SELECT l1_distance('[0,0]'::vector, '[3,4]');
  l1_distance 
 -------------
            7
 (1 row)
 
-SELECT l1_distance('[0,0]', '[0,1]');
+SELECT l1_distance('[0,0]'::vector, '[0,1]');
  l1_distance 
 -------------
            1
 (1 row)
 
-SELECT l1_distance('[1,2]', '[3]');
+SELECT l1_distance('[1,2]'::vector, '[3]');
 ERROR:  different vector dimensions 2 and 1
-SELECT l1_distance('[3e38]', '[-3e38]');
+SELECT l1_distance('[3e38]'::vector, '[-3e38]');
  l1_distance 
 -------------
     Infinity
diff --git a/test/expected/hnsw_intvec_cosine.out b/test/expected/hnsw_intvec_cosine.out
new file mode 100644
index 0000000..306e685
--- /dev/null
+++ b/test/expected/hnsw_intvec_cosine.out
@@ -0,0 +1,27 @@
+SET enable_seqscan = off;
+CREATE TABLE t (val intvec(3));
+INSERT INTO t (val) VALUES ('[0,0,0]'), ('[1,2,3]'), ('[1,1,1]'), (NULL);
+CREATE INDEX ON t USING hnsw (val intvec_cosine_ops);
+INSERT INTO t (val) VALUES ('[1,2,4]');
+SELECT * FROM t ORDER BY val <=> '[3,3,3]';
+   val   
+---------
+ [1,1,1]
+ [1,2,3]
+ [1,2,4]
+ [0,0,0]
+(4 rows)
+
+SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <=> '[0,0,0]') t2;
+ count 
+-------
+     4
+(1 row)
+
+SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <=> (SELECT NULL::intvec)) t2;
+ count 
+-------
+     4
+(1 row)
+
+DROP TABLE t;
diff --git a/test/expected/hnsw_intvec_cosine.out.diff b/test/expected/hnsw_intvec_cosine.out.diff
new file mode 100644
index 0000000..e69de29
diff --git a/test/expected/hnsw_intvec_ip.out b/test/expected/hnsw_intvec_ip.out
new file mode 100644
index 0000000..8f8a879
--- /dev/null
+++ b/test/expected/hnsw_intvec_ip.out
@@ -0,0 +1,21 @@
+SET enable_seqscan = off;
+CREATE TABLE t (val intvec(3));
+INSERT INTO t (val) VALUES ('[0,0,0]'), ('[1,2,3]'), ('[1,1,1]'), (NULL);
+CREATE INDEX ON t USING hnsw (val intvec_ip_ops);
+INSERT INTO t (val) VALUES ('[1,2,4]');
+SELECT * FROM t ORDER BY val <#> '[3,3,3]';
+   val   
+---------
+ [1,2,4]
+ [1,2,3]
+ [1,1,1]
+ [0,0,0]
+(4 rows)
+
+SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <#> (SELECT NULL::intvec)) t2;
+ count 
+-------
+     4
+(1 row)
+
+DROP TABLE t;
diff --git a/test/expected/hnsw_intvec_l2.out b/test/expected/hnsw_intvec_l2.out
new file mode 100644
index 0000000..33165b7
--- /dev/null
+++ b/test/expected/hnsw_intvec_l2.out
@@ -0,0 +1,33 @@
+SET enable_seqscan = off;
+CREATE TABLE t (val intvec(3));
+INSERT INTO t (val) VALUES ('[0,0,0]'), ('[1,2,3]'), ('[1,1,1]'), (NULL);
+CREATE INDEX ON t USING hnsw (val intvec_l2_ops);
+INSERT INTO t (val) VALUES ('[1,2,4]');
+SELECT * FROM t ORDER BY val <-> '[3,3,3]';
+   val   
+---------
+ [1,2,3]
+ [1,2,4]
+ [1,1,1]
+ [0,0,0]
+(4 rows)
+
+SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <-> (SELECT NULL::intvec)) t2;
+ count 
+-------
+     4
+(1 row)
+
+SELECT COUNT(*) FROM t;
+ count 
+-------
+     5
+(1 row)
+
+TRUNCATE t;
+SELECT * FROM t ORDER BY val <-> '[3,3,3]';
+ val 
+-----
+(0 rows)
+
+DROP TABLE t;
diff --git a/test/expected/intvec_functions.out b/test/expected/intvec_functions.out
new file mode 100644
index 0000000..983cc90
--- /dev/null
+++ b/test/expected/intvec_functions.out
@@ -0,0 +1,92 @@
+SELECT l2_distance('[0,0]'::intvec, '[3,4]');
+ l2_distance 
+-------------
+           5
+(1 row)
+
+SELECT l2_distance('[0,0]'::intvec, '[0,1]');
+ l2_distance 
+-------------
+           1
+(1 row)
+
+SELECT l2_distance('[1,2]'::intvec, '[3]');
+ERROR:  different intvec dimensions 2 and 1
+SELECT '[0,0]'::intvec <-> '[3,4]';
+ ?column? 
+----------
+        5
+(1 row)
+
+SELECT inner_product('[1,2]'::intvec, '[3,4]');
+ inner_product 
+---------------
+            11
+(1 row)
+
+SELECT inner_product('[1,2]'::intvec, '[3]');
+ERROR:  different intvec dimensions 2 and 1
+SELECT inner_product('[127]'::intvec, '[127]');
+ inner_product 
+---------------
+         16129
+(1 row)
+
+SELECT '[1,2]'::intvec <#> '[3,4]';
+ ?column? 
+----------
+      -11
+(1 row)
+
+SELECT cosine_distance('[1,2]'::intvec, '[2,4]');
+ cosine_distance 
+-----------------
+               0
+(1 row)
+
+SELECT cosine_distance('[1,2]'::intvec, '[0,0]');
+ cosine_distance 
+-----------------
+             NaN
+(1 row)
+
+SELECT cosine_distance('[1,1]'::intvec, '[1,1]');
+ cosine_distance 
+-----------------
+               0
+(1 row)
+
+SELECT cosine_distance('[1,0]'::intvec, '[0,2]');
+ cosine_distance 
+-----------------
+               1
+(1 row)
+
+SELECT cosine_distance('[1,1]'::intvec, '[-1,-1]');
+ cosine_distance 
+-----------------
+               2
+(1 row)
+
+SELECT cosine_distance('[1,2]'::intvec, '[3]');
+ERROR:  different intvec dimensions 2 and 1
+SELECT '[1,2]'::intvec <=> '[2,4]';
+ ?column? 
+----------
+        0
+(1 row)
+
+SELECT l1_distance('[0,0]'::intvec, '[3,4]');
+ l1_distance 
+-------------
+           7
+(1 row)
+
+SELECT l1_distance('[0,0]'::intvec, '[0,1]');
+ l1_distance 
+-------------
+           1
+(1 row)
+
+SELECT l1_distance('[1,2]'::intvec, '[3]');
+ERROR:  different intvec dimensions 2 and 1
diff --git a/test/expected/intvec_input.out b/test/expected/intvec_input.out
new file mode 100644
index 0000000..41e53f1
--- /dev/null
+++ b/test/expected/intvec_input.out
@@ -0,0 +1,119 @@
+SELECT '[1,2,3]'::intvec;
+ intvec  
+---------
+ [1,2,3]
+(1 row)
+
+SELECT '[-1,-2,-3]'::intvec;
+   intvec   
+------------
+ [-1,-2,-3]
+(1 row)
+
+SELECT ' [ 1,  2 ,    3  ] '::intvec;
+ intvec  
+---------
+ [1,2,3]
+(1 row)
+
+SELECT '[1.23456]'::intvec;
+ERROR:  invalid input syntax for type intvec: "[1.23456]"
+LINE 1: SELECT '[1.23456]'::intvec;
+               ^
+SELECT '[hello,1]'::intvec;
+ERROR:  invalid input syntax for type intvec: "[hello,1]"
+LINE 1: SELECT '[hello,1]'::intvec;
+               ^
+SELECT '[127,-128]'::intvec;
+   intvec   
+------------
+ [127,-128]
+(1 row)
+
+SELECT '[128,-129]'::intvec;
+ERROR:  value "128" is out of range for type intvec
+LINE 1: SELECT '[128,-129]'::intvec;
+               ^
+SELECT '[1,2,3'::intvec;
+ERROR:  malformed intvec literal: "[1,2,3"
+LINE 1: SELECT '[1,2,3'::intvec;
+               ^
+DETAIL:  Unexpected end of input.
+SELECT '[1,2,3]9'::intvec;
+ERROR:  malformed intvec literal: "[1,2,3]9"
+LINE 1: SELECT '[1,2,3]9'::intvec;
+               ^
+DETAIL:  Junk after closing right brace.
+SELECT '1,2,3'::intvec;
+ERROR:  malformed intvec literal: "1,2,3"
+LINE 1: SELECT '1,2,3'::intvec;
+               ^
+DETAIL:  Vector contents must start with "[".
+SELECT ''::intvec;
+ERROR:  malformed intvec literal: ""
+LINE 1: SELECT ''::intvec;
+               ^
+DETAIL:  Vector contents must start with "[".
+SELECT '['::intvec;
+ERROR:  malformed intvec literal: "["
+LINE 1: SELECT '['::intvec;
+               ^
+DETAIL:  Unexpected end of input.
+SELECT '[,'::intvec;
+ERROR:  malformed intvec literal: "[,"
+LINE 1: SELECT '[,'::intvec;
+               ^
+DETAIL:  Unexpected end of input.
+SELECT '[]'::intvec;
+ERROR:  intvec must have at least 1 dimension
+LINE 1: SELECT '[]'::intvec;
+               ^
+SELECT '[1,]'::intvec;
+ERROR:  invalid input syntax for type intvec: "[1,]"
+LINE 1: SELECT '[1,]'::intvec;
+               ^
+SELECT '[1a]'::intvec;
+ERROR:  invalid input syntax for type intvec: "[1a]"
+LINE 1: SELECT '[1a]'::intvec;
+               ^
+SELECT '[1,,3]'::intvec;
+ERROR:  malformed intvec literal: "[1,,3]"
+LINE 1: SELECT '[1,,3]'::intvec;
+               ^
+SELECT '[1, ,3]'::intvec;
+ERROR:  invalid input syntax for type intvec: "[1, ,3]"
+LINE 1: SELECT '[1, ,3]'::intvec;
+               ^
+SELECT '[1,2,3]'::intvec(3);
+ intvec  
+---------
+ [1,2,3]
+(1 row)
+
+SELECT '[1,2,3]'::intvec(2);
+ERROR:  expected 2 dimensions, not 3
+SELECT '[1,2,3]'::intvec(3, 2);
+ERROR:  invalid type modifier
+LINE 1: SELECT '[1,2,3]'::intvec(3, 2);
+                          ^
+SELECT '[1,2,3]'::intvec('a');
+ERROR:  invalid input syntax for type integer: "a"
+LINE 1: SELECT '[1,2,3]'::intvec('a');
+                          ^
+SELECT '[1,2,3]'::intvec(0);
+ERROR:  dimensions for type intvec must be at least 1
+LINE 1: SELECT '[1,2,3]'::intvec(0);
+                          ^
+SELECT '[1,2,3]'::intvec(16001);
+ERROR:  dimensions for type intvec cannot exceed 16000
+LINE 1: SELECT '[1,2,3]'::intvec(16001);
+                          ^
+SELECT unnest('{"[1,2,3]", "[4,5,6]"}'::intvec[]);
+ unnest  
+---------
+ [1,2,3]
+ [4,5,6]
+(2 rows)
+
+SELECT '{"[1,2,3]"}'::intvec(2)[];
+ERROR:  expected 2 dimensions, not 3
diff --git a/test/sql/copy.sql b/test/sql/copy.sql
index 2820090..7d2dc37 100644
--- a/test/sql/copy.sql
+++ b/test/sql/copy.sql
@@ -1,7 +1,7 @@
-CREATE TABLE t (val vector(3));
-INSERT INTO t (val) VALUES ('[0,0,0]'), ('[1,2,3]'), ('[1,1,1]'), (NULL);
+CREATE TABLE t (val vector(3), val2 intvec(3));
+INSERT INTO t (val, val2) VALUES ('[0,0,0]', '[0,0,0]'), ('[1,2,3]', '[1,2,3]'), ('[1,1,1]', '[1,1,1]'), (NULL, NULL);
 
-CREATE TABLE t2 (val vector(3));
+CREATE TABLE t2 (val vector(3), val2 intvec(3));
 
 \copy t TO 'results/data.bin' WITH (FORMAT binary)
 \copy t2 FROM 'results/data.bin' WITH (FORMAT binary)
diff --git a/test/sql/functions.sql b/test/sql/functions.sql
index 6235684..7e820d7 100644
--- a/test/sql/functions.sql
+++ b/test/sql/functions.sql
@@ -24,29 +24,29 @@ SELECT vector_norm('[3,4]');
 SELECT vector_norm('[0,1]');
 SELECT vector_norm('[3e37,4e37]')::real;
 
-SELECT l2_distance('[0,0]', '[3,4]');
-SELECT l2_distance('[0,0]', '[0,1]');
-SELECT l2_distance('[1,2]', '[3]');
-SELECT l2_distance('[3e38]', '[-3e38]');
+SELECT l2_distance('[0,0]'::vector, '[3,4]');
+SELECT l2_distance('[0,0]'::vector, '[0,1]');
+SELECT l2_distance('[1,2]'::vector, '[3]');
+SELECT l2_distance('[3e38]'::vector, '[-3e38]');
 
-SELECT inner_product('[1,2]', '[3,4]');
-SELECT inner_product('[1,2]', '[3]');
-SELECT inner_product('[3e38]', '[3e38]');
+SELECT inner_product('[1,2]'::vector, '[3,4]');
+SELECT inner_product('[1,2]'::vector, '[3]');
+SELECT inner_product('[3e38]'::vector, '[3e38]');
 
-SELECT cosine_distance('[1,2]', '[2,4]');
-SELECT cosine_distance('[1,2]', '[0,0]');
-SELECT cosine_distance('[1,1]', '[1,1]');
-SELECT cosine_distance('[1,0]', '[0,2]');
-SELECT cosine_distance('[1,1]', '[-1,-1]');
-SELECT cosine_distance('[1,2]', '[3]');
-SELECT cosine_distance('[1,1]', '[1.1,1.1]');
-SELECT cosine_distance('[1,1]', '[-1.1,-1.1]');
-SELECT cosine_distance('[3e38]', '[3e38]');
+SELECT cosine_distance('[1,2]'::vector, '[2,4]');
+SELECT cosine_distance('[1,2]'::vector, '[0,0]');
+SELECT cosine_distance('[1,1]'::vector, '[1,1]');
+SELECT cosine_distance('[1,0]'::vector, '[0,2]');
+SELECT cosine_distance('[1,1]'::vector, '[-1,-1]');
+SELECT cosine_distance('[1,2]'::vector, '[3]');
+SELECT cosine_distance('[1,1]'::vector, '[1.1,1.1]');
+SELECT cosine_distance('[1,1]'::vector, '[-1.1,-1.1]');
+SELECT cosine_distance('[3e38]'::vector, '[3e38]');
 
-SELECT l1_distance('[0,0]', '[3,4]');
-SELECT l1_distance('[0,0]', '[0,1]');
-SELECT l1_distance('[1,2]', '[3]');
-SELECT l1_distance('[3e38]', '[-3e38]');
+SELECT l1_distance('[0,0]'::vector, '[3,4]');
+SELECT l1_distance('[0,0]'::vector, '[0,1]');
+SELECT l1_distance('[1,2]'::vector, '[3]');
+SELECT l1_distance('[3e38]'::vector, '[-3e38]');
 
 SELECT avg(v) FROM unnest(ARRAY['[1,2,3]'::vector, '[3,5,7]']) v;
 SELECT avg(v) FROM unnest(ARRAY['[1,2,3]'::vector, '[3,5,7]', NULL]) v;
diff --git a/test/sql/hnsw_intvec_cosine.sql b/test/sql/hnsw_intvec_cosine.sql
new file mode 100644
index 0000000..c8a8ddc
--- /dev/null
+++ b/test/sql/hnsw_intvec_cosine.sql
@@ -0,0 +1,13 @@
+SET enable_seqscan = off;
+
+CREATE TABLE t (val intvec(3));
+INSERT INTO t (val) VALUES ('[0,0,0]'), ('[1,2,3]'), ('[1,1,1]'), (NULL);
+CREATE INDEX ON t USING hnsw (val intvec_cosine_ops);
+
+INSERT INTO t (val) VALUES ('[1,2,4]');
+
+SELECT * FROM t ORDER BY val <=> '[3,3,3]';
+SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <=> '[0,0,0]') t2;
+SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <=> (SELECT NULL::intvec)) t2;
+
+DROP TABLE t;
diff --git a/test/sql/hnsw_intvec_ip.sql b/test/sql/hnsw_intvec_ip.sql
new file mode 100644
index 0000000..7045951
--- /dev/null
+++ b/test/sql/hnsw_intvec_ip.sql
@@ -0,0 +1,12 @@
+SET enable_seqscan = off;
+
+CREATE TABLE t (val intvec(3));
+INSERT INTO t (val) VALUES ('[0,0,0]'), ('[1,2,3]'), ('[1,1,1]'), (NULL);
+CREATE INDEX ON t USING hnsw (val intvec_ip_ops);
+
+INSERT INTO t (val) VALUES ('[1,2,4]');
+
+SELECT * FROM t ORDER BY val <#> '[3,3,3]';
+SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <#> (SELECT NULL::intvec)) t2;
+
+DROP TABLE t;
diff --git a/test/sql/hnsw_intvec_l2.sql b/test/sql/hnsw_intvec_l2.sql
new file mode 100644
index 0000000..6c08b3d
--- /dev/null
+++ b/test/sql/hnsw_intvec_l2.sql
@@ -0,0 +1,16 @@
+SET enable_seqscan = off;
+
+CREATE TABLE t (val intvec(3));
+INSERT INTO t (val) VALUES ('[0,0,0]'), ('[1,2,3]'), ('[1,1,1]'), (NULL);
+CREATE INDEX ON t USING hnsw (val intvec_l2_ops);
+
+INSERT INTO t (val) VALUES ('[1,2,4]');
+
+SELECT * FROM t ORDER BY val <-> '[3,3,3]';
+SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <-> (SELECT NULL::intvec)) t2;
+SELECT COUNT(*) FROM t;
+
+TRUNCATE t;
+SELECT * FROM t ORDER BY val <-> '[3,3,3]';
+
+DROP TABLE t;
diff --git a/test/sql/intvec_functions.sql b/test/sql/intvec_functions.sql
new file mode 100644
index 0000000..8570d3d
--- /dev/null
+++ b/test/sql/intvec_functions.sql
@@ -0,0 +1,21 @@
+SELECT l2_distance('[0,0]'::intvec, '[3,4]');
+SELECT l2_distance('[0,0]'::intvec, '[0,1]');
+SELECT l2_distance('[1,2]'::intvec, '[3]');
+SELECT '[0,0]'::intvec <-> '[3,4]';
+
+SELECT inner_product('[1,2]'::intvec, '[3,4]');
+SELECT inner_product('[1,2]'::intvec, '[3]');
+SELECT inner_product('[127]'::intvec, '[127]');
+SELECT '[1,2]'::intvec <#> '[3,4]';
+
+SELECT cosine_distance('[1,2]'::intvec, '[2,4]');
+SELECT cosine_distance('[1,2]'::intvec, '[0,0]');
+SELECT cosine_distance('[1,1]'::intvec, '[1,1]');
+SELECT cosine_distance('[1,0]'::intvec, '[0,2]');
+SELECT cosine_distance('[1,1]'::intvec, '[-1,-1]');
+SELECT cosine_distance('[1,2]'::intvec, '[3]');
+SELECT '[1,2]'::intvec <=> '[2,4]';
+
+SELECT l1_distance('[0,0]'::intvec, '[3,4]');
+SELECT l1_distance('[0,0]'::intvec, '[0,1]');
+SELECT l1_distance('[1,2]'::intvec, '[3]');
diff --git a/test/sql/intvec_input.sql b/test/sql/intvec_input.sql
new file mode 100644
index 0000000..fefa5bf
--- /dev/null
+++ b/test/sql/intvec_input.sql
@@ -0,0 +1,28 @@
+SELECT '[1,2,3]'::intvec;
+SELECT '[-1,-2,-3]'::intvec;
+SELECT ' [ 1,  2 ,    3  ] '::intvec;
+SELECT '[1.23456]'::intvec;
+SELECT '[hello,1]'::intvec;
+SELECT '[127,-128]'::intvec;
+SELECT '[128,-129]'::intvec;
+SELECT '[1,2,3'::intvec;
+SELECT '[1,2,3]9'::intvec;
+SELECT '1,2,3'::intvec;
+SELECT ''::intvec;
+SELECT '['::intvec;
+SELECT '[,'::intvec;
+SELECT '[]'::intvec;
+SELECT '[1,]'::intvec;
+SELECT '[1a]'::intvec;
+SELECT '[1,,3]'::intvec;
+SELECT '[1, ,3]'::intvec;
+
+SELECT '[1,2,3]'::intvec(3);
+SELECT '[1,2,3]'::intvec(2);
+SELECT '[1,2,3]'::intvec(3, 2);
+SELECT '[1,2,3]'::intvec('a');
+SELECT '[1,2,3]'::intvec(0);
+SELECT '[1,2,3]'::intvec(16001);
+
+SELECT unnest('{"[1,2,3]", "[4,5,6]"}'::intvec[]);
+SELECT '{"[1,2,3]"}'::intvec(2)[];
diff --git a/test/t/020_hnsw_intvec_build_recall.pl b/test/t/020_hnsw_intvec_build_recall.pl
new file mode 100644
index 0000000..dcc6886
--- /dev/null
+++ b/test/t/020_hnsw_intvec_build_recall.pl
@@ -0,0 +1,132 @@
+use strict;
+use warnings;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+my $node;
+my @queries = ();
+my @expected;
+my $limit = 20;
+my $dim = 20;
+my $array_sql = join(",", ('(random() * 255)::int - 128') x $dim);
+
+sub test_recall
+{
+	my ($min, $operator) = @_;
+	my $correct = 0;
+	my $total = 0;
+
+	my $explain = $node->safe_psql("postgres", qq(
+		SET enable_seqscan = off;
+		EXPLAIN ANALYZE SELECT i FROM tst ORDER BY v $operator '$queries[0]' LIMIT $limit;
+	));
+	like($explain, qr/Index Scan/);
+
+	for my $i (0 .. $#queries)
+	{
+		my $actual = $node->safe_psql("postgres", qq(
+			SET enable_seqscan = off;
+			SELECT i FROM tst ORDER BY v $operator '$queries[$i]' LIMIT $limit;
+		));
+		my @actual_ids = split("\n", $actual);
+		my %actual_set = map { $_ => 1 } @actual_ids;
+
+		my @expected_ids = split("\n", $expected[$i]);
+
+		foreach (@expected_ids)
+		{
+			if (exists($actual_set{$_}))
+			{
+				$correct++;
+			}
+			$total++;
+		}
+	}
+
+	cmp_ok($correct / $total, ">=", $min, $operator);
+}
+
+# Initialize node
+$node = get_new_node('node');
+$node->init;
+$node->start;
+
+# Create table
+$node->safe_psql("postgres", "CREATE EXTENSION vector;");
+$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v intvec($dim));");
+$node->safe_psql("postgres",
+	"INSERT INTO tst SELECT i, ARRAY[$array_sql] FROM generate_series(1, 10000) i;"
+);
+
+# Generate queries
+for (1 .. 20)
+{
+	my @r = ();
+	for (1 .. $dim)
+	{
+		push(@r, int(rand(256)) - 128);
+	}
+	push(@queries, "[" . join(",", @r) . "]");
+}
+
+# Check each index type
+my @operators = ("<->", "<#>", "<=>");
+my @opclasses = ("intvec_l2_ops", "intvec_ip_ops", "intvec_cosine_ops");
+
+for my $i (0 .. $#operators)
+{
+	my $operator = $operators[$i];
+	my $opclass = $opclasses[$i];
+
+	# Get exact results
+	@expected = ();
+	foreach (@queries)
+	{
+		my $res = $node->safe_psql("postgres", "SELECT i FROM tst ORDER BY v $operator '$_' LIMIT $limit;");
+		push(@expected, $res);
+	}
+
+	# Build index serially
+	$node->safe_psql("postgres", qq(
+		SET max_parallel_maintenance_workers = 0;
+		CREATE INDEX idx ON tst USING hnsw (v $opclass);
+	));
+
+	# Test approximate results
+	my $min = 0.99;
+	test_recall($min, $operator);
+
+	$node->safe_psql("postgres", "DROP INDEX idx;");
+
+	# Build index in parallel in memory
+	my ($ret, $stdout, $stderr) = $node->psql("postgres", qq(
+		SET client_min_messages = DEBUG;
+		SET min_parallel_table_scan_size = 1;
+		CREATE INDEX idx ON tst USING hnsw (v $opclass);
+	));
+	is($ret, 0, $stderr);
+	like($stderr, qr/using \d+ parallel workers/);
+
+	# Test approximate results
+	test_recall($min, $operator);
+
+	$node->safe_psql("postgres", "DROP INDEX idx;");
+
+	# Build index in parallel on disk
+	# Set parallel_workers on table to use workers with low maintenance_work_mem
+	($ret, $stdout, $stderr) = $node->psql("postgres", qq(
+		ALTER TABLE tst SET (parallel_workers = 2);
+		SET client_min_messages = DEBUG;
+		SET maintenance_work_mem = '4MB';
+		CREATE INDEX idx ON tst USING hnsw (v $opclass);
+		ALTER TABLE tst RESET (parallel_workers);
+	));
+	is($ret, 0, $stderr);
+	like($stderr, qr/using \d+ parallel workers/);
+	like($stderr, qr/hnsw graph no longer fits into maintenance_work_mem/);
+
+	$node->safe_psql("postgres", "DROP INDEX idx;");
+}
+
+done_testing();