The Internet Archive is now rate-limiting the Wayback Machine.

A September 15 post says protective measures are in place against high-volume automated traffic, with blocked requests now surfacing as HTTP 429. No rate limits, no API changes, no documented access pattern published, only an admission the filters sometimes catch real people and an address to email if you're blocked in error. Tooling that reads Wayback snapshots at volume should expect intermittent 429s with no published budget to code against.