Code · moj-analytical-services · 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

5.2 MB of source

1.6k

files at HEAD

across every analysed repository

0 B

on disk as mirrors

full history, every branch and tag

119.3 MB

largest repository

splink

What stands out

One archived repository holds 59% of all the bytes.

splink is 119.3 MB of git - a 2013 static snapshot of www.gov.uk, not source code. It single-handedly makes HTML the largest language by volume (1% 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 0% 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.

67% 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
splink	Python	119.3 MB	11,965	551	active
user-guidance	HTML	48.4 MB	1,840	299	active
uk_address_matcher	Python	21.7 MB	1,707	238	active
splink_datasets	-	3.9 MB	5	13	active
pydbtools	Python	2.1 MB	553	52	active
opg-pipeline-builder	Python	1.5 MB	556	90	active
laurium	Python	1.5 MB	395	47	active
splink_udfs	C++	924.7 kB	174	43	active
mojchart	R	695.3 kB	49	54	active
dbtools	R	415.7 kB	149	42	active
ukam_os_builder	Python	378.9 kB	124	57	active
Rs3tools	R	145.4 kB	120	33	active
Rdbtools	R	143.4 kB	119	31	active
metadata_schema	-	39.9 kB	38	13	active
actions-build-and-push-to-ecr	-	34.8 kB	53	3	active
actions-mojap-package-depends	Python	33.8 kB	53	5	active
actions-cross-account-ecr	Python	19.5 kB	16	6	active
actions-lint-python	-	9.2 kB	15	2	archived
actions-poetry-pypi-release	-	8.2 kB	10	5	active
actions-lint-yaml	-	7.2 kB	12	2	archived