> ## Documentation Index
> Fetch the complete documentation index at: https://circle-devdocs-test-ai-codegen-component.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Signing APIs

> You can use Circle's API platform's signing APIs on blockchains where Wallets do not have full blockchain infrastructure support.

Wallets offers key signing capabilities to a broader range of blockchains where
there isn't full blockchain infrastructure support, such as NEAR and other EVM
chains. You can leverage Circle's advanced MPC key management for signing, and
integrate with your own node and data service of choice. Circle offers SDKs and
APIs to manage user authentication, wallet creation, and signing capabilities
that integrate with your blockchain infrastructure.

<Note>
  Developer-controlled wallets support signing on NEAR and other EVM chains.
  User-controlled wallets support signing on other EVM chains.
</Note>

<Frame>
  <img src="https://mintcdn.com/circle-devdocs-test-ai-codegen-component/SJLeV2p3IVpxs9EY/w3s/images/signing-sa-walletssign01.png?fit=max&auto=format&n=SJLeV2p3IVpxs9EY&q=85&s=d0cf12b87dd3714e602364cb04610059" width="2096" height="824" data-path="w3s/images/signing-sa-walletssign01.png" />
</Frame>

See our step-by-step tutorials for how to sign transactions on different
blockchains:

* [Sign Transactions on Solana](/wallets/sign-tx-solana)
* [Sign Transactions on EVM chains](/wallets/sign-tx-evm)
* [Sign Transactions on NEAR](/wallets/sign-tx-near)

## Signing endpoints

You can use the following API endpoints for signing capabilities such as sign
transaction, sign typed data, or sign message.

* `POST` `/developer/sign/message`
* `POST` `/developer/sign/typedData`
* `POST` `/developer/sign/transaction`
* `POST` `/developer/sign/delegateAction`
* `POST` `/user/wallets`
* `POST` `/user/sign/message`
* `POST` `/user/sign/typedData`
* `POST` `/user/sign/transaction`

<Warning>
  **Lazy Deployment on Smart Contract Accounts (SCAs):**

  Circle's Smart Contract Accounts (SCAs) use a **lazy deployment** strategy. This
  means that the wallet contract is only deployed to the blockchain upon the first
  transaction.

  If you attempt to use signing endpoints such as `/sign/message` or
  `/sign/typedData` before the wallet is deployed, the request will fail with an
  error. You must ensure that the user performs a first onchain transaction (for
  example, sending tokens or interacting with a contract) to deploy the wallet
  before attempting to sign arbitrary messages or typed data.
</Warning>

<Note>
  For unsupported EVM chains, create a wallet with a `blockchain` value of `EVM`
  or `EVM-TESTNET` for signing. These virtual blockchain parameters are not tied
  to specific EVM chains. For details, see
  [Sign transactions on EVM chains](/wallets/sign-tx-evm).

  For `EVM-TESTNET` wallets, you can sign transactions on the blockchains listed
  in [Chain IDs for signing transactions](/w3s/sign-tx-chain-id). Once you
  transition to mainnet, you can use your `EVM` wallet to sign transactions on
  any EVM-compatible chains.
</Note>

## Disclaimer

Using the sign transaction endpoints involves critical actions that can impact
your assets and transactions.

Signing transactions carries inherent security risks. Malicious actors can trick
users into signing what appears to be a legitimate transaction message. This
could potentially allow them to gain unauthorized access to your funds. Always
ensure that you are signing transactions only from trusted sources and verify
the legitimacy of transaction requests before proceeding.

<Danger>
  If you have created Wallets on an EVM-compatible chain such as Ethereum,
  Polygon, Avalanche, or Arbitrum, an EVM wallet created under the same wallet
  set maps to the same addresses.

  In these cases, it is extremely important that you do not use the EVM wallet to
  sign transactions for existing Wallets on those chains; for example, sign
  transaction with chainID = 137 signs MATIC transaction.

  Your Wallet transactions will be stuck and you are responsible for any resulting
  consequences.
</Danger>

## Programmable Wallet capabilities

The following table shows the difference in Programmable Wallet capabilities
offered on fully managed blockchains vs. Near and other blockchains.

| Capability Category      | Fully managed blockchains                                                                                                                                                                                                                                                 | NEAR and other EVM chains                                                                                                                                       |
| ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Wallet Features          | User authentication <br /><br /> Wallet creation <br /><br /> Full transaction lifecycle management: <br />- Signing tx or messages <br />- Broadcast <br />- Monitor deposit <br />- Index tx and balances                                                               | User authentication <br /><br /> Wallet creation <br /><br /> Signing tx or messages                                                                            |
| Wallet Infrastructure    | Developer-controlled wallets <br /><br /> User-controlled wallets                                                                                                                                                                                                         | Developer-controlled wallets <br /><br /> User-controlled wallets (except NEAR)                                                                                 |
| Circle Contracts Support | Contracts APIs support for most of the chains that PW APIs support (given that the specified chains support smart contracts)                                                                                                                                              | Not supported                                                                                                                                                   |
| Gas Station Support      | Access to Gas Station to enable gas sponsorship for all smart contract account wallets <br /><br /> Self-serve ability to set up Paymaster policies <br /><br /> Available for chains supported by PW that supports smart contract accounts or native gas station for EOA | N/A<br /><br /> Supports only EOA wallets. As Gas Station and paymaster policies require the use of SCA Wallets, Gas Station is not supported in this offering. |