Proof of existence for files: anchor a SHA-256 hash on Base, look up proofs. Paid with x402.
Free
One server, in finance & commerce. Proof of existence for files: anchor a SHA-256 hash on Base, look up proofs. Paid with x402.
Finance & Commerce
Proof of existence for files: anchor a SHA-256 hash on Base, look up proofs. Paid with x402.
The rest either hold an API key issued by the publisher or ask for nothing.
Listed without a verification tick. Read the listing before installing.