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Changelog

Changes to the API that you might notice, newest first. During early access some will break existing requests, and those are marked.

Serve CSV exports gzipped

22 October 2026. Breaking.

Each format listed by /v1/exports may now carry gzipBytes: present when the file is stored gzipped, as CSV is, giving its size as sent with Content-Encoding: gzip.
A CSV export is no longer served in byte ranges: a request with Range gets the whole file. Download it in one request instead.

21 October 2026

The API now serves website place profiles, facts, ward areas and the docs catalogue at /v1/atlas-pages/{page-id}.json. Containment and lineage lookups are available at /v1/atlas-lookups/{lookup-id}.json. Existing requests are unchanged; artifact shapes follow the website.

18 October 2026

A request that arrives while a worker is at its concurrent request limit now waits up to one second for a free slot instead of being refused at once. 503 Server Busy is now returned only when the wait times out or too many requests are already waiting. Self-hosted instances can tune this with ATLAS_MAX_QUEUED_REQUESTS and ATLAS_QUEUE_TIMEOUT_MS.

18 October 2026. Breaking.

Map-resource joins in JSON and Parquet now accept at most 250,000 source records and 16 MiB of uncompressed column payload. Oversized joins return 422 Map Join Budget Exceeded, with no partial table. Follow links.data to retrieve source observations in pages as JSON, CSV or NDJSON.

18 October 2026. Breaking.

A worker now admits at most 16 active requests by default, configurable with ATLAS_MAX_CONCURRENT_REQUESTS. Excess requests return 503 Server Busy with Retry-After: 1 without queuing. Retry with backoff. Health, readiness, metrics and preflight requests remain available.

18 October 2026. Breaking.

Children geometry now refuses collections with more than 1,000 children. Children geometry and box queries with a tier refuse requests that process more than 250,000 source vertices before simplification with 422 Geometry Budget Exceeded.
For box queries, reduce limit or omit tier to fetch identities. For larger geometry collections, follow the refusal's links.downloads to the release metadata and its prebuilt downloads. Oversized requests return no partial collection.

17 October 2026

The API is live at /v1. Routes, parameters and responses may still change while it's in early access.