By the numbers

A quantitative snapshot of the rails/rails repo. Data collected on 2026-04-30 against main at commit 0e53474dd25bb06cc87c07a75ffec49d3490152c.

Size

The repo is dominated by Active Record, Active Support, and Action Pack. Counts below are lines in lib/ only (production Ruby), excluding test/, generators, and templates.

xychart-beta horizontal
    title "Lines of Ruby in lib/ per component"
    x-axis ["actioncable", "actionmailbox", "actionmailer", "actionpack", "actiontext", "actionview", "activejob", "activemodel", "activerecord", "activestorage", "activesupport", "railties"]
    y-axis "Lines"
    bar [4198, 728, 2755, 28574, 2580, 19401, 4743, 9017, 69692, 3904, 32407, 15862]

Component	lib/ lines	Notes
activerecord	69,692	The ORM dominates — ~33% of all production Ruby
activesupport	32,407	Core extensions plus pub/sub, cache, current attributes, etc.
actionpack	28,574	Action Controller + Action Dispatch combined
actionview	19,401	Templates and helpers
railties	15,862	CLI, generators, application boot
activemodel	9,017	Validations, callbacks, dirty tracking
activejob	4,743	Background jobs
actioncable	4,198	WebSockets
activestorage	3,904	File uploads
actionmailer	2,755	Outbound email
actiontext	2,580	Rich text
actionmailbox	728	Inbound email
Total lib/	193,861

Including tests (test/), the repo contains ~395,000 lines of Ruby and ~1,260 *_test.rb files.

File counts (Ruby + ERB + JS + Markdown)

Top-level directories ranked by source files:

Directory	Files
activerecord/	1,144
activesupport/	517
actionview/	500
actionpack/	449
railties/	358
activestorage/	183
activemodel/	156
activejob/	136
actiontext/	135
actioncable/	115
guides/	113
actionmailer/	111
actionmailbox/	104
tools/	60

Activity

• Total commits on main: 97,490
• First commit: 24 November 2004 ("Initial")
• Latest commit (at snapshot): 30 April 2026 (Tokyo time)
• Commits in the last 12 months: ~6,047
• Commits in the last 24 months: ~9,400+
• Commits in 2024: 4,012
• Commits in 2025 (YTD): 3,297

The codebase has averaged roughly 4,000-5,000 commits per year for several years running, with a long-term mean closer to ~4,500/year over the project's lifetime.

Most active components in the last 12 months (by commits)

Rough commit count for changes touching each component (last 12 months):

Component	~Commits
activerecord	700+
activesupport	400+
actionview	300+
actionpack	300+
railties	200+
activejob	120+

Active Record is consistently the most-changed component, reflecting the ongoing work on adapters, encryption, multi-DB, and async queries.

Bot-attributed commits

Searching git log for Co-authored-by: lines mentioning common bot accounts (dependabot[bot], github-actions[bot], factory-droid[bot], etc.) yields a very small number of commits — well under 1% of the total. Rails is overwhelmingly authored by humans. This is a lower bound on AI-assisted work since inline AI tools like Copilot leave no co-author trace.

Largest source files

File	Lines
actionpack/test/dispatch/routing_test.rb	5,343
railties/test/application/configuration_test.rb	5,308
actionview/test/template/form_helper_test.rb	4,300
actionview/test/template/date_helper_test.rb	3,710
activerecord/test/cases/associations/has_many_associations_test.rb	3,353
activerecord/test/cases/relations_test.rb	2,796
actionview/lib/action_view/helpers/form_helper.rb	2,766
actionview/test/template/form_with_test.rb	2,553

The longest production file is actionview/lib/action_view/helpers/form_helper.rb at 2,766 lines — Rails' form-builder DSL has accumulated 20 years of helpers.

TODO/FIXME/HACK

A grep of *.rb for TODO|FIXME|HACK:

• Files containing at least one comment: 56
• Total comments: 131

A modest number for a 200K-line codebase, but worth a tour. See how-to-contribute/patterns-and-conventions for how the codebase tends to handle these.

Releases

The release tag history (most recent first):

v8.1.3, v8.1.2.1, v8.1.2, v8.1.1, v8.1.0,
v8.0.5, v8.0.4.1, v8.0.4, ...

Active maintenance branches at the time of writing: 8.1-stable, 8.0-stable, 7.2-stable, 7.1-stable, plus main (8.2.0.alpha).

Test-to-code ratio

Counting *_test.rb files alone: 1,262 test files vs ~3,400 Ruby source files in lib/ directories — roughly 1 test file for every 2.5 source files. By line count, test/ outweighs lib/ (the repo total is ~395K Ruby lines vs ~194K in lib/), giving a test-to-code ratio of approximately 1.0+ for tests vs. production code.

Dependencies

• The top-level Gemfile declares ~50 direct dev dependencies (databases, integration gems, dev tools).
• The Gemfile.lock resolves to ~1,000 lines of dependencies.
• The 12 component gemspecs collectively declare ~25 runtime dependencies (Rack, Loofah, Mail, Marcel, Nokogiri, Tzinfo, etc.).

For more, see reference/dependencies.