API error codes and what to do

Errors look like {"error": {"code": "...", "message": "..."}}.

• 400 `invalid_request`: a field is missing or malformed. The message names the field.
• 401 `unauthorized`: missing, wrong, or revoked key. Send Authorization: Bearer wl_live_....
• 402 `credits_exhausted`: out of credits on the free plan, or a key's daily cap or your overage limit was reached.
• 403 `forbidden`: a read-only key tried an endpoint that reveals contact details.
• 404 `person_not_available`: no match, or the person has opted out. You're not charged.
• 409 `duplicate_request`: you reused an Idempotency-Key with a different request body.
• 413 `payload_too_large`: more than 1,000 rows in one /bulk call. Split it up.
• 429 `rate_limited`: too many requests per second. Wait for the Retry-After seconds. Limits per second: Free 2, Starter 10, Growth 25, Scale 100.
• 503 `provider_unavailable`: a data source is temporarily unavailable. Retry later; you weren't charged.