Polymarket API authentication: choose the task first

By PredictionToolkit · Updated 2026-10-05

There is no universal Polymarket key for every operation. This source-based guide helps select the interface and identify private-access requirements; it does not report an authenticated integration test.

Before you begin

• Define a read-only dataset or a specific private CLOB action.
• Use current official documentation; an operator-controlled wallet is relevant only when private access is necessary.
• Plan to keep secrets out of this directory, public logs and issue reports.

Choose the API without creating credentials

Gamma provides public market metadata without a trading key. Data API handles positions and activity; CLOB handles books and separately private order management. Record the chosen host and check whether the exact action is public before generating credentials. This selection is a documentation decision, not a successful API request.

Identify the L1 prerequisite

For private CLOB access, the provider describes an operator-controlled EIP-712 ClobAuth wallet signature to create or derive API credentials. Read signer address, current timestamp, nonce and signature requirements. The output of this step is a list of prerequisites, not a signed message or credential. Reading the specification does not establish eligibility.

Plan L2 request signing

The documented second layer uses API credentials for HMAC-SHA256 private-request signing. Identify the five required headers and exact body serialization in current official documentation. Order placement additionally requires a wallet signature authorizing the order: L2 request authentication does not replace it. Plan storage and revocation outside this site.

Check your result

• Name the public or private API surface and explain why credentials are or are not needed.
• Distinguish L1 credential creation, L2 request headers and the separate signed order.
• Obtain provider-owned eligibility, secure-storage and revocation instructions before creating any real credential.

What this guide has not verified

No message was signed, credential created, rotated or revoked, authenticated request sent or order placed for this guide. Account eligibility and a rotation procedure were not established. A published endpoint does not prove uptime, latency or trading permission. Never submit private keys, secrets, passphrases or signatures to the directory.