The data behind KnowYourSponsor

These files are the deliberately open, auditable layer behind the core sponsor-register claims on this site. They are rebuilt from named public sources and need no account. They are not a download of KnowYourSponsor's private archive, internal matching rules or paid reports.

Start here

If you only want one thing, it is regional_changes.json: the employers that gained or lost a licence in the last seven days, split by town. That is the part the official register does not publish, because it shows only who holds a licence today and never who stopped.

There is also an RSS feed if you would rather not write any code at all.

The files

data/source_status.json

Latest sponsor-register source and pipeline integrity receipt.

{"status": "verified", "runId": "...", "publishedAt": "...", "retrievedAt": "...", "source": {"url": "...", "sha256": "..."}, "pipeline": {...}, "input": {...}, "output": {...}, "manifestSha256": "..."}

Identifies and validates our mirror build; GOV.UK remains the authoritative current source.

data/sponsors.json

Every licensed sponsor on the register.

{"updated": "...", "source": "...", "sponsors": [[name, town, county, industry, [routes], rating], ...]}

About 10MB uncompressed, served gzipped. Rows are arrays, not objects, to keep it small.

data/company_flags.json

Employers whose company record raises a question at Companies House.

{"updated": "...", "snapshot": "YYYY-MM-01", "stats": {...}, "companies": {"Employer Name": {"number": "...", "status": "...", "flags": ["not_active", ...], "dates": {...}}}}

Keyed by the employer's name exactly as the register spells it. Matched by name, so treat it as a pointer to the Companies House record rather than proof.

data/occupations.json

Official occupation titles, Skilled Worker labels and published salary rates used by the job checker.

{"sourceUpdated": "...", "generalThreshold": 0, "hoursBasis": 37.5, "occupations": [{"code": "...", "jobType": "...", "titles": [...], "eligibility": "...", "standardAnnual": 0, ...}]}

Rebuilt weekly from the GOV.UK occupation, going-rate and job-rules pages. A suggested title is not an assigned occupation code; the vacancy duties still need checking.

data/vacancy_rulesets.json

Versioned standard-salary rule metadata used to reproduce saved vacancy checks.

{"schemaVersion": 1, "policy": "append-only", "rulesets": [{"id": "...", "version": "...", "sourceUpdated": "...", "generalThreshold": 0, ...}]}

Existing versions are never silently rewritten. Applicant-specific and special salary rules remain unresolved unless separately governed evidence is available.

data/early_warning.json

Aggregate evidence on whether Companies House signals precede sponsor-register removal.

{"status": "collecting|measured", "coverage": {...}, "publicationGate": {...}}; measured releases also include aggregate distributions.

Interim counts and intervals are withheld until the documented snapshot, duration and paired-sample gate passes.

data/evidence_coverage.json

The release receipt for safe company-identity links, historical CoS links, the separate 2025 CoS-use disclosure and evidence publication gates.

{"updated": "...", "register": {...}, "companyIdentity": {...}, "historicalCos": {...}, "cosUsage2025": {...}, "earlyWarningTrackRecord": {...}}

Coverage says where evidence can be attached without guessing. It is not an accuracy, eligibility or safety score.

data/regional_changes.json

The same changes, split by town or city.

{"updated": "...", "window_days": 7, "totals": {...}, "regions": {"London": {"added": [...], "removed": [...], "slug": "london"}, ...}}

Built for exactly one job: sending someone the changes in their own area.

data/market_trends.json

Aggregate dated movement from the verified daily comparison archive.

{"status": "collecting|established", "coverage": {...}, "currentRecords": 0, "totals": {...}, "daily": [...], "sectors": [...]}

Contains no employer names. Coverage and missing days are part of the result. Movement is not hiring or visa demand.

data/new_sponsors.json

Sponsor name-and-town records first observed in the last 7 days.

{"updated": "...", "window_days": 7, "claim": "...", "new": [row, ...]}

First observed is not the date a licence was granted.

data/removed_sponsors.json

Exact sponsor name-and-town records no longer observed in the last 7 days.

{"updated": "...", "window_days": 7, "claim": "...", "removed": [row, ...]}

The source does not state why a record changed; the same sponsor name may remain elsewhere.

data/meta.json

Counts and the last update time. Small, cheap to poll.

{"updated": "...", "total": 0, "added_recently": 0, "removed_recently": 0, "window_days": 7}

Poll this first and only fetch the big files when "updated" has moved.

feed.xml

RSS feed, one item per day that changed.

RSS 2.0

For readers, and for anything that turns a feed into email.

feeds/<city-or-industry>.xml

The same changes, filtered to one city or one industry.

RSS 2.0, one item per employer

One per landing page, so feeds/london.xml and feeds/healthcare-care.xml both exist. Each item has a permanent guid, so polling it will not re-notify you about the same employer twice. This is the free version of a filtered feed; email delivery and watchlists are the paid one.

How to use it kindly

The pipeline runs once a day, at 05:30 UTC. Polling more often than hourly only costs you bandwidth.
Check meta.json first. It is small, and its updated value tells you whether anything moved.
These are static files, not a supported commercial API. There is no authentication or uptime guarantee. Poll reasonably, cache your own copy and check meta.json before fetching larger files.
A row is an array, in this order: name, town, county, industry, routes, rating. Industry is derived from a safe, specific Companies House SIC link when available, with sponsor-name wording as a fallback, not official data.

Source licences and KnowYourSponsor work

The underlying register is Crown copyright and is published under the Open Government Licence v3.0. Companies House and every other public source retain their own rights and licence terms. Nothing here restricts the rights those source licences give you in the underlying public information.

KnowYourSponsor's original software, writing, database compilation, derived analyses, full historical archive, reports and visual materials are separate from those public-source rights. Individual checking, verification, research and modest reuse of this documented public layer are welcome. Systematic extraction or commercial republication of the KnowYourSponsor enrichment, white-labelling it, or using it to operate a competing service requires written permission.

This clarification applies to access from 21 September 2026. It does not change a public source's licence or attempt to withdraw permission already granted for an earlier copy.

The register contains 127,826 sponsor name-and-town records. One legal employer can appear more than once.

What is not here

The public trend file contains aggregate movement and coverage. We also keep the employer-level daily archive privately, which can answer narrower questions such as when one record first appeared or what changed in a given month without publishing every historical employer event.

That history only exists because it has been collected day by day. GOV.UK publishes today's register and never what left it, so it cannot be reconstructed after the fact by anyone, including us.

Need the history, or a cut of your own?

If you need a longer history, a filtered feed for one region or sector, or a regular export for your team, email me and tell me what you are trying to do. It is easier to build the thing somebody actually asked for than to guess at it.

Useful things to say: which sectors or regions you care about, how far back you need, and how you would rather receive it. I reply to everything.

Email hello@knowyoursponsor.co.uk Or see what it costs