Code · UKHomeOffice · 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

376.5 MB of source

216.7k

files at HEAD

across every analysed repository

0 B

on disk as mirrors

full history, every branch and tag

1.4 GB

largest repository

RDS-Templates

What stands out

One archived repository holds 21% of all the bytes.

RDS-Templates is 1.4 GB of git - a 2013 static snapshot of www.gov.uk, not source code. It single-handedly makes HTML the largest language by volume (24% 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 0% of archived repositories but only 3% 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.

81% 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
RDS-Templates	PowerShell	1.4 GB	1,532	470	active
asl-reporting	Perl	854.2 MB	3,477	3,371	active
hocs-serenity-automation	Java	360.7 MB	3,321	447	active
hbase	Java	281.0 MB	38,122	4,231	active
kops	Go	273.7 MB	15,303	13,019	active
piwik	PHP	193.6 MB	29,616	9,776	active
keycloak	Java	168.0 MB	15,185	11,929	active
posters	-	166.7 MB	490	322	active
conf_synth_refresh	Python	153.0 MB	54	13	active
eba-envbuild-tool	HTML	123.4 MB	8	3,407	active
ckan	Python	120.0 MB	19,323	1,711	active
cdp-nifi	-	119.3 MB	4,891	0	archived
drt-v2	Scala	114.9 MB	11,714	1,073	active
eba-cloud-tools	HTML	110.8 MB	1	1,149	active
mongo-tools	Go	103.3 MB	2,787	2,282	active
pttg-fs-service	Groovy	100.6 MB	146	180	archived
govuk-frontend	JavaScript	99.7 MB	9,513	799	active
aspel-workspace	JavaScript	81.9 MB	25,263	2,965	active
cert-manager	Go	79.0 MB	6,857	1,380	active
rtp-amazon-sqs-lib	Scala	76.8 MB	136	31	active