Glossary / API integration / Retry-After
A ParlayAPI glossary entry

Retry-After

Retry-After is an HTTP response header that tells a client how long to wait before retrying, expressed in seconds (or as an HTTP date). It arrives on 429 rate-limit responses and some 5xx responses, and honoring it is the difference between a polite client and a blocked one.

In practice

# The two cases a client must handle
        429 + Retry-After: 30     ->  sleep 30s, then retry
        503 + Retry-After: 5      ->  sleep 5s, then retry
        # No header present?  Exponential backoff with jitter:
        delay = min(base × 2^attempt + random_jitter, max_delay)

Retrying immediately after a 429 compounds the problem and reads as abuse. Production clients centralize this logic in one HTTP wrapper so every call site inherits correct behavior - including a retry budget, so a persistent outage fails fast instead of piling up sleeping workers.

Where it shows up in ParlayAPI

Respect Retry-After on any 429 from credit-metered endpoints (limits are described at /limits). Consumers that keep hitting the ceiling usually want either response caching or streaming delivery instead of tighter polling loops - see rate limit.

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