Blueshift Rate Limits

Blueshift's API rate limiting is advisory prose, not a runtime contract. There are published throughput recommendations on the bulk endpoints and hard batch caps enforced with 413, but the API returns NO rate-limit headers of any kind — no X-RateLimit-*, no RateLimit-*, no Retry-After. A client discovers it has exceeded the limit only by receiving a 429 with a one-line message, and then has to guess the backoff. Note also that the article most people find when searching "Blueshift rate limiting" is about MESSAGE-SENDING throughput (campaign, channel and user-level message caps), which is a different concept from API request limits; both are recorded here and kept separate.