translate/index.ts — 429 retries at 1s, 2s, 4s ignore Retry-After, retry budget exhausted in 7 seconds

Finding

calculateRetryDelay in packages/utils/src/translate/index.ts uses pure exponential backoff on 429 responses. Retry-After is never consulted.

RETRY_CONFIG = {
  maxRetries: 3,
  baseDelay: 1000ms,
  backoffMultiplier: 2,
  maxDelay: 10000ms
}

429 and 5xx are handled identically.

What happens under rate limiting

When a translation provider returns 429 with Retry-After: 60:

• Retry 1 fires at 1s — inside cooldown
• Retry 2 fires at 2s — inside cooldown
• Retry 3 fires at 4s — inside cooldown
• All three retries fail
• Retry budget exhausted in 7 seconds
• Provider said wait 60 seconds. Client didn't listen.

The consequence

On a 60-second provider cooldown, the entire retry budget is consumed in 7 seconds against requests that cannot succeed.

The correct behavior

On 429 with Retry-After:

• Read the header value
• Wait at least that duration before retrying
• Fall back to exponential backoff only when Retry-After is absent

Related pattern

retry-after-ignored-under-concurrency

Corpus reference: https://github.com/SirBrenton/pitstop-truth