V1 endpoints
These endpoints require a Client API Key or Client Session Token (CST) as a bearer token.
Clients
Create the client's wallet
POST
https://mpc-client.portalhq.io/v1/generate
This endpoint generates MPC shares for both SECP256K1 (EVM, etc) and ED25519 (Solana, XRP, etc) curves (a Portal wallet).
After receiving MPC shares from this endpoint, be sure to verify the shares with this endpoint before attempting to sign.
Headers
Authorization*
String
Bearer <Client API Key>
Content-Type*
String
application/json
Body Parameters
You can leave the request body empty.
Example Response
Send the client's assets
POST
https://mpc-client.portalhq.io/v1/assets/send
This endpoint allows you to easily send a token the client holds to another address.
The Send Assets
endpoint builds, signs, and submits a transaction to an RPC gateway.
Important: A 200 response only confirms that the transaction was received by the RPC gateway — it does not mean the transaction is confirmed on-chain. The transaction must first be placed in the mempool of the RPC gateway nodes, submitted to miner/validator nodes, and then validated and finalized by the network. This process can take seconds to minutes, depending on the blockchain.
Headers
Authorization*
String
Bearer <Client API Key>
Content-Type*
String
application/json
Body Parameters
chain
*
String
The blockchain network (e.g. "ethereum", "sepolia", "solana", "solana-devnet", or a CAIP-2 chain ID like "eip155:11155111")
to
*
String
The recipient's address.
token
*
String
The token contract address (for ERC20 tokens on EVM chains) or the mint address (for Solana SPL tokens). You can also use "USDC" or "USDT" for the respective tokens. For native token transfers, use "NATIVE"
.
amount
*
String
The amount of tokens to send ("0.1" is 0.1 USDC)
rpcUrl
String
The node provider RPC URL. Not required for Solana or Solana Devnet.
nonce
String
The hex string of the nonce to set on the transaction ("0x01" sets the nonce of the transaction to 1). Note that the hex string needs to include the "0x" and for single digits to include a leading zero like "0x0".
metadataStr
String
Optional metadata string for the transaction.
When submitting multiple transactions for a single client in quick succession (or in parallel), each transaction may initially have the same nonce if the blockchain hasn’t processed the earlier ones yet. This can cause errors, as the RPC gateway interprets identical nonces as attempts to overwrite transactions in the mempool.
To prevent this, track the nonce in your application and increment it manually for each transaction sent to the Send Assets
endpoint, ensuring unique nonces for concurrent requests.
Example Response
If your client is using Account Abstraction, then transactionHash
is actually a User Operation hash. You can manually look up the user operation hash here.
Sign a transaction or message by chain
POST
https://mpc-client.portalhq.io/v1/sign
This endpoint allows you to sign a transaction or message by chain.
Headers
Authorization*
String
Bearer <Client API Key>
Content-Type*
String
application/json
Body Parameters
method
*
String
The signer RPC method (e.g. "personal_sign", "eth_sendTransaction", "sol_signAndSendTransaction", etc).
params
*
String
A JSON stringified array of the parameters for the RPC method (e.g. "[\"test\"]").
chainId
*
String
The blockchain network (a CAIP-2 chain ID like "eip155:11155111" for Sepolia).
to
*
String
The recipient's address.
rpcUrl
*
String
The node provider RPC URL.
metadataStr
String
Optional metadata string for the transaction.
Example Response
Sign a transaction or message by curve
POST
https://mpc-client.portalhq.io/v1/raw/sign/:curve
This endpoint allows you to sign a raw message by curve.
Headers
Authorization*
String
Bearer <Client API Key>
Content-Type*
String
application/json
Path Parameters
curve
*
String
The curve you want to use (e.g. SECP256K1
for EVM chains and ED25519
for Solana).
Body Parameters
param
*
String
A hex string of the digest to sign without the leading 0x
(e.g. "param": "7369676e2074686973"
).
Example Response
Back up the client's wallet
POST
https://mpc-client.portalhq.io/v1/backup
This endpoint allows you to create backup shares for your wallet.
Headers
Authorization*
String
Bearer <Client API Key>
Content-Type*
String
application/json
Body Parameters
Example Response
Recover the client's wallet
POST
https://mpc-client.portalhq.io/v1/recover
This endpoint allows you to recover shares for your wallet using your backup shares.
Headers
Authorization*
String
Bearer <Client API Key>
Content-Type*
String
application/json
Body Parameters
Example Response
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