> ## Documentation Index
> Fetch the complete documentation index at: https://docs.panofx.com/llms.txt
> Use this file to discover all available pages before exploring further.

# MPC signers

> Sign offers with Turnkey or MPCVault instead of a local keyfile.

The node's signer backend is pluggable. A keyfile is the default; Turnkey and MPCVault keep the key in an
MPC service and sign each offer through its API.

**In the app:** **Wallet → Use a wallet I already have → Connect Turnkey** (or MPCVault). It tests a
signature before it saves anything.

**On the command line,** put one of the blocks below in your policy. The API key never goes in the file.

<Tabs>
  <Tab title="Turnkey">
    ```yaml theme={null}
    signer:
      backend: turnkey
      turnkey:
        organization_id: <your organization id>
        sign_with: <the wallet account address>
        api_public_key: <compressed P-256 public key, hex>
    ```

    Set `PANOFX_TURNKEY_API_PRIVATE_KEY_FILE` to a file holding the API private key (or
    `PANOFX_TURNKEY_API_PRIVATE_KEY` to the key itself). Turnkey can also send the Permit2 approvals through
    `panofx-node approve`.

    When `sign_with` is a private key id rather than an address, set `address` too. `base_url` overrides the
    API host.
  </Tab>

  <Tab title="MPCVault">
    ```yaml theme={null}
    signer:
      backend: mpcvault
      mpcvault:
        vault_uuid: <vault uuid>
        address: <the vault's EVM address>
        client_signer_public_key: <your client signer's public key>
    ```

    Set `PANOFX_MPCVAULT_API_TOKEN_FILE` (or `PANOFX_MPCVAULT_API_TOKEN`). MPCVault signs typed data and
    messages only, so `approve` prints the exact `approve(Permit2, max)` call to send from the MPCVault
    console for each token. `base_url` overrides the API host.
  </Tab>
</Tabs>

<Warning>
  Run `panofx-node signer test --policy policy.yaml` after either change. MPC signing must stay under the
  700 ms budget, or the node declines with `signer_unavailable` and never wins a quote.
</Warning>

The relay records the signer type (`keyfile`, `turnkey` or `mpcvault`) with each heartbeat, and shows it in
the resolver directory.