By the numbers

Data collected on 2026-04-30, against commit 16034ecf3b7cc5da96a1f0c324d0eed927267877 of the main branch.

Size

The repository is dominated by Go source code, with a sizeable React/TypeScript UI on the side.

xychart-beta horizontal
    title "Source files by extension (top languages)"
    x-axis ["Go", "yml", "tsx", "ts", "md", "yaml", "js", "sh", "proto", "y"]
    y-axis "Files" 0 --> 800
    bar [704, 299, 135, 98, 68, 52, 11, 16, 4, 1]

Type	Count
Total Go files	704
Go source files (excluding _test.go)	439
Go test files	265
Lines of Go source (excluding tests)	~159,000
Lines of Go tests	~184,000
Lines of TypeScript / TSX (UI, excluding node_modules)	~43,000
Markdown files	68
YAML files	351 (yml: 299, yaml: 52)
Protobuf definitions	4
GoYACC grammar	1 (promql/parser/generated_parser.y)

The single largest non-test file is promql/engine.go at 4,700 lines. The largest test files are tsdb/db_test.go (9,700), tsdb/head_test.go (8,300), and tsdb/db_append_v2_test.go (7,700). The two binaries' main packages are concentrated in two files: cmd/prometheus/main.go (2,200 lines) and cmd/promtool/main.go (1,500 lines).

Top-level area sizes

xychart-beta horizontal
    title "Approximate Go source LOC per top-level area"
    x-axis ["tsdb", "promql", "discovery", "scrape", "storage", "web", "rules", "model", "config", "notifier", "util", "tracing"]
    y-axis "kLOC" 0 --> 80
    bar [60, 30, 25, 18, 16, 16, 8, 14, 5, 4, 22, 1]

The tsdb/ tree is the largest area by line count and the most complex by surface area (block format, WAL, head, agent variant). promql/, scrape/, and discovery/ are the next largest.

Activity

The repository has been active continuously since 2012-11-24. Commits per calendar year:

xychart-beta horizontal
    title "Commits per year (2013–2026)"
    x-axis ["2013", "2014", "2015", "2016", "2017", "2018", "2019", "2020", "2021", "2022", "2023", "2024", "2025", "2026 (YTD)"]
    y-axis "Commits" 0 --> 3000
    bar [841, 332, 1219, 1293, 1602, 1035, 1017, 1038, 1365, 970, 1379, 2768, 1788, 798]

Window	Commits
All-time	17,472
Last 90 days	592
Last 30 days	156
Last 7 days	14

2024 has the highest commit count on record (2,768) — coinciding with the v3.0 release cycle. 2025 stayed elevated. The 2026 figure is partial (year-to-date as of April).

Files most actively changed in the last 90 days

File	Changes
go.mod	32
go.sum	30
promql/engine.go	27
cmd/prometheus/main.go	25
docs/configuration/configuration.md	21
tsdb/head_test.go	19
promql/promqltest/testdata/native_histograms.test	18
.github/workflows/ci.yml	18
tsdb/head.go	14
tsdb/db.go	14
Makefile.common	14
web/ui/package-lock.json	13
cmd/promtool/main.go	12
storage/remote/queue_manager_test.go	11
promql/functions.go	11

The TSDB head and PromQL engine remain the hottest source files — that has been true for years.

Bot-attributed commits

A lower bound (signatures only):

Source	Count
Authored by *[bot]@ or noreply@	2,750 (~16% of all-time commits)
With any Co-authored-by: trailer	864
With a Co-authored-by: mentioning a bot	486

Renovate is the dominant non-human contributor (renovate[bot]); the Prometheus team runs Renovate aggressively for npm and Go dependency upkeep. Inline AI-assist (Copilot etc.) leaves no trace in git history, so the real share of AI-assisted work is necessarily higher than this number.

Releases

Release cadence is fixed: a feature minor every six weeks. Recent tags (newest first):

v3.11.3 — v3.11.2 — v3.11.1 — v3.11.0 — v3.10.0 — v3.10.0-rc.1 — v3.10.0-rc.0 — v3.9.1 — v3.9.0 — v3.8.0

Each user-visible major (e.g. v3.11.0) is mirrored by an internal v0.311.0 tag for Go-module consumers; the mapping rule is documented in README.md.

Maintainership signal

• 6 general maintainers listed in MAINTAINERS.md.
• 25+ area maintainers across cmd/promtool, discovery/<sd>, tsdb, tsdb/agent, web/ui, promql, storage/remote, etc.
• Top recent committers (90 days): Julien Pivotto, Bartlomiej Plotka, Julius Volz, Ganesh Vernekar, Bryan Boreham, György Krajcsovits.

See Maintainers for the per-subsystem ownership table.

Test-to-code ratio

Roughly 1.16:1 — the test corpus is larger than the production code. The TSDB and PromQL areas drive this; nearly every behaviour is exercised by a combination of _test.go files, PromQL .test cases, and OpenAPI golden tests.