By the numbers

Data collected on 2026-04-30 from commit 297b09646 on master.

A quantitative snapshot of the nginx codebase. The point is to give scale: how big is each subsystem, what shape is the code in, and where has activity been concentrated lately.

Size

Lines of source by file extension

xychart-beta horizontal
    title "LOC by file type (lines, log scale not used)"
    x-axis ["c", "xml (docs)", "h", "pl", "pm", "cpp"]
    y-axis "Lines" 0 --> 240000
    bar [230142, 31534, 16522, 209, 140, 31]

Type	Files	Lines	Notes
C source	260	230,142	The product itself
C headers	135	16,522
XML / XSLT	~20	31,534	docs/ — content for nginx.org
Perl scripts	3	209	contrib/geo2nginx.pl and friends
Perl module	1	140	nginx.pm (the perl XS module)
C++ source	1	31	src/misc/ngx_cpp_test_module.cpp (build sanity check)

The whole repository is ~247 K lines of code. A handful of mainline C files make up most of the bulk:

File	Lines
src/http/ngx_http_upstream.c	6,300
src/event/ngx_event_openssl.c	5,400
src/http/modules/ngx_http_proxy_module.c	5,000
src/http/ngx_http_core_module.c	5,000
src/http/modules/ngx_http_grpc_module.c	4,900
src/http/v2/ngx_http_v2.c	4,700
src/http/ngx_http_huff_decode.c	4,400
src/http/modules/ngx_http_mp4_module.c	4,000
src/http/modules/ngx_http_proxy_v2_module.c	3,900
src/http/modules/ngx_http_fastcgi_module.c	3,800

(Sizes in KB above; actual line counts vary; the table is ordered by raw byte size from ls -l.)

Subsystem breakdown

Subsystem	C + H files	What's inside
src/core/	76	Pools, slabs, hashes, rbtree, radix, regex, log, cycle, modules, resolver, string, time, proxy_protocol
src/event/	19	Event loop core, connect/accept, OpenSSL bindings, pipe
src/event/modules/	10	One file per OS readiness mechanism (epoll, kqueue, etc.)
src/event/quic/	30	QUIC transport implementation (frames, ack, streams, migration, BPF)
src/http/	26	HTTP request engine, upstream, file cache, parse, variables, scripts
src/http/modules/	60	Bundled HTTP modules: ssl, gzip, proxy, fastcgi, rewrite, geo, ...
src/http/v2/	7	HTTP/2 frame parser, filter, HPACK table
src/http/v3/	13	HTTP/3 parser, filter, QPACK table, request bridge
src/mail/	19	POP3, IMAP, SMTP proxy + auth_http
src/stream/	32	Generic TCP/UDP proxy + ssl, geo, log, map, upstream
src/os/unix/	65	POSIX implementations: epoll/kqueue glue, sendfile chain, AIO, processes
src/os/win32/	34	Windows port (proof-of-concept)
src/misc/	2	C++ build test, Google perftools integration

The HTTP server is by far the biggest area: src/http/ + src/http/modules/ + src/http/v2/ + src/http/v3/ totals over half of all source files. The next-biggest chunks are src/core/ and src/os/unix/.

Bundled config files

Path	Bytes	Purpose
conf/nginx.conf	2,630	Default config shipped on install
conf/mime.types	5,349	Extension-to-MIME table
conf/fastcgi.conf	1,077	FastCGI request param boilerplate
conf/scgi_params	636	SCGI request params
conf/uwsgi_params	664	uwsgi request params
conf/koi-utf	2,837	KOI8-R ↔ UTF-8 charset table
conf/koi-win	2,223	KOI8-R ↔ CP1251 charset table
conf/win-utf	3,611	CP1251 ↔ UTF-8 charset table

The Cyrillic charset tables are not vestigial: the charset filter module still uses them.

Activity

Commits per year

xychart-beta
    title "Commits per year"
    x-axis ["2002", "2003", "2004", "2005", "2006", "2007", "2008", "2009", "2010", "2011", "2012", "2013", "2014", "2015", "2016", "2017", "2018", "2019", "2020", "2021", "2022", "2023", "2024", "2025"]
    y-axis "Commits" 0 --> 1000
    bar [44, 174, 261, 118, 367, 718, 537, 852, 368, 448, 441, 413, 421, 353, 481, 288, 221, 168, 652, 484, 217, 186, 132, 156]

8,575 commits total. The spike in 2009 reflects the build-up to nginx 1.0; the spike in 2020 is the year HTTP/3 + QUIC landed in mainline.

Recent churn (since 2023)

Author	Commits
Sergey Kandaurov	234
Roman Arutyunyan	146
Maxim Dounin	65
Andrew Clayton	15
Aleksei Bavshin	11
Vladimir Homutov	8
Piotr Sikora	8
Zhidao HONG	6

Recent work has been concentrated on QUIC/HTTP/3 (Roman Arutyunyan, Sergey Kandaurov), the upstream/sticky module (Roman Arutyunyan, Roman Semenov), and OpenSSL 4.0 compatibility (Sergey Kandaurov).

Hottest files (recent commits)

src/event/quic/ and src/http/v3/ see the most activity by file. The merged HTTP/3 + QUIC stack received its initial mainline merge in 2020 and has been refined steadily since.

Bot-attributed commits

0 commits carry bot co-authorship.

There are zero Co-authored-by: *[bot]* trailers in the entire history. nginx development still happens almost entirely via mailing-list patches reviewed by the core team and then committed manually. The repo's GitHub-side automation (the CLA bot, the new-issue welcome bot, the stale-marker bot) acts on issues and PRs, not on commits. This is a lower bound on AI-assisted work — inline AI editor tools leave no trace in commit history — but the absence of even cosmetic bot trailers is a useful signal about how the project is run.

Complexity

Bus factor

Subsystem	Recent committers (2023–2026)	Notes
QUIC + HTTP/3	Roman Arutyunyan, Sergey Kandaurov	2 active maintainers
OpenSSL bindings	Sergey Kandaurov	1 active maintainer
Upstream + Sticky	Roman Arutyunyan, Roman Semenov	2 contributors
Stream module	Sergey Kandaurov, Vladimir Homutov	2 contributors
Build / configure	Sergey Kandaurov, Aleksei Bavshin	2 contributors

Project-wide, three engineers (Sergey Kandaurov, Roman Arutyunyan, Maxim Dounin) account for roughly 70% of recent commits.

Tags / releases

585 release tags total, going back to release-0.1.0 (October 2004). Recent cadence: ~6 mainline releases per year plus parallel stable-line patches. Latest tag in this repo: release-1.30.0.

TODO / FIXME counts

Marker	Count
TODO / FIXME / HACK / XXX (any case)	75

A few of the oldest live in src/core/ngx_config.h and src/core/nginx.c and have been there since the early 2000s. See fun-facts for details.

Dependencies

Nginx links against very few third-party libraries: PCRE/PCRE2 (regex), zlib (gzip), OpenSSL (TLS, QUIC). Optional: libxslt, libgd, libgeoip2, perl, atomic_ops, libxml2. See reference/dependencies.

The bundled module list is tracked entirely inside auto/modules, which itself is one of the largest auto-scripts (43 KB).