Code · nhsx · 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

1.5 GB of source

16k

files at HEAD

across every analysed repository

0 B

on disk as mirrors

full history, every branch and tag

293.2 MB

largest repository

audere

What stands out

One archived repository holds 12% of all the bytes.

audere is 293.2 MB of git - a 2013 static snapshot of www.gov.uk, not source code. It single-handedly makes HTML the largest language by volume (96% 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.

39% 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
audere	TypeScript	293.2 MB	3,704	4,056	active
au-tableau-analytics	TSQL	284.1 MB	671	206	active
synthea	Java	279.3 MB	4,120	848	active
open-cyber	HTML	240.3 MB	383	677	active
open-cyber-interim	HTML	226.7 MB	352	741	active
diabetes-inequalities	Python	159.7 MB	198	35	active
AIF_Allocation_Tool	Python	111.0 MB	191	13	active
stm-survey-text	R	107.5 MB	61	31	active
nccid-ct-slice-lung-classification	Python	73.5 MB	18	9	active
nhs-app-analytics-dashboard	-	55.7 MB	99	6	active
patient-online-mapping	HTML	52.7 MB	70	55	active
commercial-data-healthcare-predictions	Jupyter Notebook	48.8 MB	53	20	active
nhs_time_of_travel	HTML	46.9 MB	561	80	active
antibody-web	TypeScript	37.5 MB	653	297	active
standards-registry-discovery	HTML	27.0 MB	163	518	active
skunkworks-renal-health-prediction	Python	23.6 MB	28	218	active
ambulance-DES	HTML	22.1 MB	10	119	active
AnalyticsUnit	CSS	21.4 MB	217	168	active
skunkworks-parkinsons-detection	HTML	20.3 MB	56	140	active
Mental-Health	-	19.6 MB	126	72	active