API Design · Junior · Question 16 of 75

What does `503 Service Unavailable` usually mean?

1The resource was deleted
2The client needs to log in
✓Correct answer: The server is temporarily unable to handle requests (overload, maintenance); Retry-After may say when to try again

Explanation

It's a retryable error, unlike most 4xx. Load balancers also return 503 when no healthy instance is available.

Further reading

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