L2 Signature
A meta-transaction signature from a Polymarket API key registered to a proxy wallet, used for routine order placement without exposing the root EOA.
Definition
An L2 signature on Polymarket is produced by an API signing key that has been registered (via an L1 signature) as an authorized delegate of a specific proxy wallet. L2 signatures are lighter-weight than L1 signatures in the sense that they authorize only CLOB-level operations (order placement, cancellation, querying) rather than on-chain fund movements. The underlying proxy wallet contract validates L2 signatures for order settlement.
In practice
In normal bot operation, every order placement call uses an L2 signature. The ClobClient holds the API key loaded from secrets.json and automatically signs each order request with it. Because L2 signing keys are delegate keys, they can be revoked without moving funds — the root EOA retains full control over the proxy wallet's USDC and outcome tokens. If a bot's secrets.json is compromised, rotating the L2 API key (using an L1 signature) prevents unauthorized trading while funds remain safe. This separation of concerns is a core security feature of Polymarket's proxy wallet architecture.