Code · communitiesuk · UK Public Sector GitHub Observatory

Language figures come from GitHub's own per-repository byte counts, which measure source rather than a single headline label. File counts and repository sizes come from the mirrors themselves. The two tell different stories, and the difference is the point.

The codebase

languages in use

221.4 MB of source

64.2k

files at HEAD

across every analysed repository

0 B

on disk as mirrors

full history, every branch and tag

648.3 MB

largest repository

terraform-provider-aws

What stands out

One archived repository holds 33% of all the bytes.

terraform-provider-aws is 648.3 MB of git - a 2013 static snapshot of www.gov.uk, not source code. It single-handedly makes HTML the largest language by volume (17% of all source bytes). Any size or language statistic that does not exclude it is measuring an archive, not a codebase.

Sizes here are GitHub's reported figures.

This organisation was harvested with blobless partial clones, which fetch every commit and file path but not file contents, so there is no local size to measure against. Checked elsewhere in this dataset against 1,526 fully mirrored repositories, GitHub's reported size is accurate to within about six percent.

Ruby is the house language, but its share is falling.

Ruby is the primary language of 6% of archived repositories but only 8% of live ones. Python, Go, TypeScript and HCL have taken the difference - the signature of a shift from monolithic Rails publishing apps toward data pipelines, infrastructure-as-code and platform tooling.

Most repositories are small; a handful are enormous.

51% of repositories are under a megabyte of git data. The estate is not a monolith - it is a very long tail of small services, gems and prototypes around a few large publishing applications.

Languages, two ways

By volume of source

Bytes of code. Dominated by archived static HTML.

By number of repositories

How many repositories name each language as their primary one. A better guide to what engineers actually work in.

Live estate versus archive

The same language ranking, split by whether the repository is still active. The shift is the clearest signal of technical direction in the whole dataset.

Active repositories

Archived repositories

Scale

Repository size distribution

Git data per repository, log-ish buckets.

Commits against files

Each circle is a repository, sized by number of distinct authors. Both axes are logarithmic. The diagonal band is the normal relationship between codebase size and churn; outliers above it are long-lived apps with heavy iteration, below it are dumps and imports.

The shape of a repository

Directory layout is the cheapest reliable signal of what a repository actually is. app/ with config/ and spec/ is a Rails application; src/ with test/ is Java or Node. Counted by how many repositories contain each top-level directory at HEAD.

Most common top-level directories

Most common file extensions

By total file count across the estate.

The twenty largest repositories

Repository	Language	Git size	Commits	Files	Status
terraform-provider-aws	Go	648.3 MB	117,027	19,735	active
lookup_generator	Jupyter Notebook	199.7 MB	16	67	active
mhclg-epc-alpha	HTML	76.4 MB	856	1,507	archived
postcodes.io	HTML	59.8 MB	2,479	362	active
data_science_for_policy	Python	53.9 MB	5	55	active
submit-social-housing-lettings-and-sales-data	Ruby	51.1 MB	20,504	2,827	active
dluhc-prpp-alpha-application	Python	43.2 MB	29	128	active
system-design-hub	-	36.0 MB	32	11	active
digital-form-builder	TypeScript	32.4 MB	3,665	1,064	archived
ukraine-sponsor-resettlement	JavaScript	31.1 MB	3,378	348	active
funding-service-design-post-award-data-store	Python	29.4 MB	3,902	477	active
prsdb-webapp	Kotlin	28.9 MB	11,278	2,508	active
funding-service-design-glossary	CSS	27.9 MB	10	168	active
local-cyber-support-docs	-	27.8 MB	167	43	active
core-design-history	JavaScript	27.7 MB	227	169	active
pkg_gov_uk_dashboards	Python	26.3 MB	2,495	182	active
epb-home-energy-model	Rust	24.6 MB	3,553	1,277	active
prs-ombudsman-design-history	Nunjucks	24.3 MB	57	100	active
eip-ero-print-api	Kotlin	21.9 MB	1,456	515	active
digital-form-builder-upstream-upgrade	TypeScript	19.8 MB	961	799	active