FAQ
Q: Do I need an API key?
A: No. The free tier allows 30 requests/hour per IP without authentication. For higher limits (1,000/hr), contact us for a Premium key.
Q: What happens if I exceed the rate limit?
A: You'll receive a 429 Too Many Requests error. Free tier resets hourly. Premium tier also resets every hour.
Q: How accurate is the validation?
A: The API uses regex pattern matching to verify address format. It does NOT check if the address exists on-chain or has funds.
Q: Can I validate multiple addresses at once?
A: No, the API validates one address per request. For bulk validation, loop through your addresses programmatically.
Q: Which chains are supported?
A: 124+ chains. Use GET /v1/chains to get the current list.
Q: Does this validate smart contract addresses?
A: For EVM chains, yes - smart contract addresses follow the same format as EOA (externally owned accounts).
Q: What's the difference between BTC legacy, P2SH, and Bech32?
A: All are valid Bitcoin address types. The API accepts:
- Legacy (P2PKH): Starts with
1 - P2SH: Starts with
3 - Bech32 (SegWit): Starts with
bc1
Q: How do I get a Premium API key?
A: Buy the premium membership on Patreon.
Support
For Premium API keys, issues, or questions:
- Email: support@chaincheckapi.com
- Documentation:
/openapi.jsonfor OpenAPI spec
Last Updated: January 2026
API Version: 1.0.0