What is HTTP 429? · Ultra Transcenders glossary

The HTTP status a service sends when it is throttling a caller, for example RequestRateTooLarge in Cosmos DB. Callers should wait for the period given in the retry-after header before retrying.

Also called Too Many Requests.

In the Ultra Transcenders books

AI-200

Each book explains HTTP 429 in context, with comparison tables and the common traps.

Terms in this definition

HTTP
Hypertext Transfer Protocol, which sends data in clear text; VCF interfaces and APIs instead use HTTPS.
Cosmos DB
NoSQL database distributed globally, offering writes in multiple regions, automatic indexing and latency below 10 ms.

Related terms

Exponential backoff
Retry approach that waits twice as long after every failure, adds random jitter and stops after a set number of attempts; advised for HTTP 429 and temporary 5xx errors.
TPM
Tokens per minute, the measure for Azure OpenAI quota and deployment rate limits. Going over it produces an HTTP 429 response.

See HTTP 429 in the full glossary