Dependencies

PostgreSQL has no language-level package manifest. External libraries are detected at configure time. This page summarizes what the build looks for and what it does with each.

Mandatory or near-mandatory

These are required for a useful production build:

Library	Detected by	Used for
libc	toolchain	Everything. POSIX or Win32.
GNU make ≥ 3.81	configure	autoconf build. (Meson is an alternative.)
bison	configure	gram.y, pl_gram.y, repl_gram.y, etc. Cached output is shipped, so a stable build can sometimes skip it; development cannot.
flex	configure	scan.l, pl_scanner.l, etc. Same caveat as bison.
Perl ≥ 5.14	configure	Code generation (genbki.pl, Gen_fmgrtab.pl, etc.) and the TAP test harness.
ICU	--with-icu	Collation support. Effectively mandatory in recent versions.
OpenSSL	--with-openssl	TLS/SSL, plus pgcrypto. Production deployments effectively require it.
zlib	configure	Compressed dumps.

Frequently used optional

Built-in only when the corresponding flag is passed:

Library	Flag	Purpose
LLVM	--with-llvm	JIT'd expression and tuple-deforming.
liburing	--with-liburing	Linux io_uring AIO method.
libxml2	--with-libxml	xml data type and XPath.
libxslt	--with-libxslt	xml2 contrib's XSLT functions.
Readline or libedit	--with-readline (default)	psql line editing.
Perl headers	--with-perl	PL/Perl.
Python ≥ 3.x headers	--with-python	PL/Python.
Tcl headers	--with-tcl	PL/Tcl.
GSSAPI / Kerberos	--with-gssapi	GSSAPI authentication and gss connection encryption.
PAM	--with-pam	PAM authentication.
LDAP	--with-ldap	LDAP authentication.
systemd	--with-systemd	sd_notify integration with systemd-managed services.
liblz4	--with-lz4	LZ4 compression for TOAST and WAL.
libzstd	--with-zstd	Zstd compression for TOAST and WAL.
bonjour / DNS-SD	--with-bonjour	macOS service advertisement.
selinux + libsepol	--with-selinux	sepgsql contrib (Linux-only mandatory access control).
DTrace	--enable-dtrace	Static probes (Solaris, FreeBSD, Linux via systemtap).

Build-time-only

These are needed at build time but not at runtime:

• bison + flex — regenerate gram.c, scan.c, etc.
• Perl — runs genbki.pl and friends.
• a working pg_config — when building extensions out of tree via PGXS.

Runtime-only

• POSIX or Windows OS APIs.
• A POSIX shell (for archive_command, etc., when configured).

Where the configure logic lives

• autoconf: configure.ac at the repo root, with the generated configure checked in. Macros under config/. Per-feature checks like PGAC_CHECK_OPENSSL etc.
• Meson: meson.build at the repo root and meson_options.txt. Mirrors the autoconf options with a -D<name>=<value> interface.
• Header detection: Many #ifdef HAVE_xxx_H checks throughout the source. The project adds them as new platform variants surface.

Platform support

Officially tested on:

• Linux (glibc, musl), macOS, Windows (MSVC + MinGW), FreeBSD, OpenBSD, NetBSD, illumos, AIX, HP-UX, Solaris.

The project's buildfarm runs continuous builds on a wide set of these. New platform support comes mostly from contributors at vendors who run PostgreSQL on those platforms.

Vendored code

The repo carries a small amount of bundled third-party code:

• src/backend/regex/ — a fork of Henry Spencer's regex library, heavily modified.
• src/backend/snowball/ — Martin Porter's stemmers for full-text search.
• src/timezone/ — a copy of the IANA tz database, refreshed on tz updates.
• src/port/getopt_long.c — a portable copy when the system one isn't usable.
• src/include/getopt_long.h — same.
• src/tools/pg_bsd_indent/ — a fork of BSD indent used by pgindent.

Vendored copies are updated periodically by the maintainers of the corresponding subsystems; you'll see commits like Update time zone data files to tzdata release 2026b. in the history.

Out-of-tree extensions

PostgreSQL's package ecosystem is much wider than contrib/. Extensions — from PostGIS to TimescaleDB to pgvector — live in their own repositories and link against the installed libpq and server headers via PGXS. They do not appear in the dependencies story for the core build but are part of the broader project ecosystem.