By the numbers

Data collected on 2026-04-30 against commit 28af95a2d.

Size

Language	Lines
Go (*.go)	246,054
Markdown (*.md)	12,799
Shell (*.sh)	4,615
YAML (*.yaml, *.yml)	1,696
Protobuf (*.proto)	1,936

xychart-beta horizontal
    title "Source lines by language"
    x-axis ["Go", "Markdown", "Shell", "Protobuf", "YAML"]
    y-axis "Lines" 0 --> 250000
    bar [246054, 12799, 4615, 1936, 1696]

The Go count includes generated protobuf stubs (the four largest Go files in the repo are protobuf output, see "Complexity hotspots" below).

Module breakdown (Go workspace)

Module path	*.go files	Go lines
server/	390	85,523
tests/	263	64,921
api/	20	38,057
client/ (pkg + v3)	189	23,021
pkg/	87	11,057
etcdctl/	50	8,048
tools/	56	6,520
cache/	18	4,764
etcdutl/	21	2,507
contrib/	11	1,612
Total	~1,105	~246,000

api/ is small in file count but large in lines because it contains generated *.pb.go files for the public protobuf surface; see reference/data-models.md.

History at a glance

• First commit: 20ca21a3f on 2013-06-06 — store module and unit test for store.
• Latest commit at wiki time: 28af95a2d on 2026-04-29 — fix to etcdutl hash timeout (PR #21686).
• Total commits on main: 24,682.
• Tagged releases include 3.0 → 3.6 series for the etcd module, plus parallel tag namespaces for api, server, client, client/pkg, pkg, etcdctl, etcdutl, and tests (see git tag output).

Major release timeline

Release	First tag date
v3.0.0	2016-06-30
v3.1.0	2017-01-20
v3.2.0	2017-06-09
v3.3.0	2018-02-01
v3.4.0	2019-08-30
v3.5.0	2021-06-15
v3.6.0	2025-05-15

The 3.5 → 3.6 gap (almost four years) is the longest in the project's history; 3.6 was finally cut shortly before this wiki was generated.

Activity

Commits per month over the last ~2 years on main (excerpt):

Month	Commits
2024-09	85
2024-10	161
2024-11	143
2024-12	128
2025-01	202
2025-02	180
2025-03	154
2025-04	121
2025-05	267
2025-06	144
2025-07	183
2025-08	166
2025-09	171
2025-10	145
2025-11	96
2025-12	70
2026-01	136
2026-02	140
2026-03	111
2026-04	112

The May 2025 spike aligns with the 3.6.0 release.

Bot-attributed commits

Bot co-authorship via Co-authored-by: trailers in the last 12 months: 0 counted commits. This does not mean no AI assistance was used — inline AI tools leave no trace in git log — only that the project does not currently use bots that sign their commits as co-authors. The recurring dependabot[bot] author you see in shortlogs commits as the dependabot user directly rather than as a co-author. Over the last 12 months, dependabot accounts for roughly 1.1% of authored commits.

Complexity (largest source files)

Lines	File
24,822	api/etcdserverpb/rpc.pb.go (generated)
3,270	api/etcdserverpb/gw/rpc.pb.gw.go (generated)
2,948	api/etcdserverpb/raft_internal.pb.go (generated)
2,476	server/etcdserver/server.go
2,265	server/etcdserver/api/v3election/v3electionpb/v3election.pb.go (generated)
2,215	tests/integration/v3_grpc_test.go
2,150	tests/robustness/validate/validate_test.go
2,137	api/etcdserverpb/rpc_grpc.pb.go (generated)
1,802	tests/integration/clientv3/lease/leasing_test.go
1,715	tests/integration/cache_test.go
1,703	tests/framework/integration/cluster.go
1,585	tests/integration/clientv3/watch/v3_watch_test.go
1,576	server/etcdserver/server_test.go
1,541	api/membershippb/membership.pb.go (generated)
1,402	server/embed/config.go

The two non-generated outliers — server/etcdserver/server.go (2,476 lines) and server/embed/config.go (1,402 lines) — are the long-standing focal points of the project; both have been refactored repeatedly but remain the single source of truth for EtcdServer and the Config API.

TODOs and FIXMEs

grep -rE "TODO|FIXME|HACK" --include="*.go" finds 441 occurrences across 196 files. See cleanup-opportunities/todos-and-fixmes.md for a sampling.

Test-to-code ratio

tests/ alone contributes ~65k lines, on top of the _test.go files that ship next to each package. Combined with the tests/robustness/ linearizability harness (Jepsen-style), correctness tests are roughly the same order of magnitude as production code — a deliberate design choice for a system in etcd's role.