Reliable downloads depend on immutable object versions, correct range behavior, and access decisions that remain valid during resume.

Versioned objects skip purge

app-1.4.2.exe never needs invalidation. latest.exe does. Prefer hashes in the name and a tiny pointer file with a short TTL or purge.

The delivery model

How it works

CDN for large file downloads

  1. 01PublishUpload a complete versioned file and integrity digest.
  2. 02TransferServe full or partial content as requested.
  3. 03ResumeValidate the requested range against the same object.
Conceptual model for this configuration. The actual path depends on provider policy and application behavior.

Large-file optimisation

Large downloads put sustained demand on throughput, storage, and upstream transfer. Test realistic object sizes, partial responses, and concurrent downloads in your key regions.

Range requests and resumes

Download managers will request ranges. Validate a large test object through the distribution before launch day.

Do not Brotli a zip

Leave already-compressed binaries alone. Brotli and Gzip are for text. Recompressing a zip wastes CPU and can hurt.

Validate before production

Request a small byte range and inspect the 206 response, Content-Range, and body length. Pause and resume a download across token expiry if access is protected. Verify the final digest against the release manifest.

  • Record the configuration and expected result before changing traffic.
  • Keep evidence of the test and a working rollback for the previous behavior.

Sources & further reading