API Reference

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

Name	Type	Description
Authorization*	String	Bearer <Client API Key>
Content-Type*	String	application/json

Body Parameters

You can leave the request body empty.

{}

Example Request

Be sure to replace the [token] with either a Client API Key or a Client Session Token.

curl --request POST \
  --url https://mpc-client.portalhq.io/v1/generate \
  --header 'Authorization: Bearer [token]' \
  --header 'Content-Type: application/json' \
  --data '{}'

Example Response

200: OK Success

{
  "SECP256K1": {
    "share": "eyJjbG...",
    "id": "cm0r6nkek00ej10dwwx8wdjmf"
  },
  "ED25519": {
    "share": "eyJjbG...",
    "id": "cm0r6nk7c00hbzefaq9s93s0x"
  }
}

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

Name	Type	Description
Authorization*	String	Bearer <Client API Key>
Content-Type*	String	application/json

Body Parameters

Name	Type	Description
share*	String	The MPC share generated from “Create Wallets” for a specific curve.
chain*	String CAIP-2 Chain ID or one of: "monad-testnet" "base" "base-sepolia" "ethereum" "bitcoin-segwit" "bitcoin-segwit-testnet" "bitcoin-p2wpkh" "bitcoin-p2wpkh-testnet" "polygon" "polygon-amoy" "celo" "celo-alfajores" "sepolia" "solana" "solana-devnet" "stellar" "stellar-testnet" "tron" "tron-nile" "tron-shasta"	The blockchain network.
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 RPC node provider URL that the transaction will be submitted through. 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 Request

Be sure to replace the [token] with either a Client API Key or a Client Session Token.

curl --request POST \
  --url https://mpc-client.portalhq.io/v1/assets/send \
  --header 'Authorization: Bearer [token]' \
  --header 'Content-Type: application/json' \
  --data '{
	"share": "share",
	"chain": "ethereum",
	"to": "0xdFd8302f44727A6348F702fF7B594f127dE3A902",
	"token": "NATIVE",
	"amount": "0.0001"
}'

Example Response

200: OK Success

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.

{
  "transactionHash": "0x02073df9ba08895d681f80ae45440ba57e766602c97ee6321df5ac81bca900cc",
  "metadata": {
    "amount": "0.01",
    "rawAmount": "10000000000000000",
    "tokenAddress": "0xfFf9976782d46CC05630D1f6eBAb18b2324d6B14",
    "tokenDecimals": 18
  }
}

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

Name	Type	Description
Authorization*	String	Bearer <Client API Key>
Content-Type*	String	application/json

Body Parameters

Name	Type	Description
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\”]”).
share*	String	The MPC share generated from “Create Wallets” for a specific curve.
chainId*	String	The blockchain network (a CAIP-2 chain ID like “eip155:10143” for Monad Testnet).
to*	String	The recipient’s address.
rpcUrl*	String	The node provider RPC URL.
metadataStr	String	Optional metadata string for the transaction.

Example Request

Be sure to replace the [token] with either a Client API Key or a Client Session Token.

curl --request POST \
  --url https://mpc-client.portalhq.io/v1/sign \
  --header 'Authorization: Bearer [token]' \
  --header 'Content-Type: application/json' \
  --data '{
	"share": "share",
	"method": "eth_sendTransaction",
	"params": "{\"value\": \"0x01\",\"from\": \"\",\"to\": \"0xdFd8302f44727A6348F702fF7B594f127dE3A902\",\"data\": \"\"}",
	"rpcUrl": "https://api.portalhq.io/rpc/v1/eip155/10143",
	"chainId": "eip155:10143"
}'

Example Response

200: OK Success

{
  "data": "0xf7a6a07fa599db56fca50fa1202670b59054e7ed452ea57b3f5b43148b8bdb165beb3a4b0fd532162a1f0fd475de1a9ecd07c95186f7a0856ce1bffa45e3acc91b"
}

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

Name	Type	Description
Authorization*	String	Bearer <Client API Key>
Content-Type*	String	application/json

Path Parameters

Name	Type	Description
curve*	String	The curve you want to use (e.g. SECP256K1 for EVM chains and ED25519 for Solana).

Body Parameters

Name	Type	Description
params*	String	A hex string of the digest to sign without the leading 0x (e.g. "params": "7369676e2074686973").
share*	String	The MPC share generated from “Create Wallets” for a specific curve.

Example Request

Be sure to replace the [token] with either a Client API Key or a Client Session Token.

curl --request POST \
  --url https://mpc-client.portalhq.io/v1/raw/sign/SECP256K1 \
  --header 'Authorization: Bearer [token]' \
  --header 'Content-Type: application/json' \
  --data '{
	"params": "123",
	"share": "[share]"
}'

Example Response

200: OK Success

The data field is a hex string without the leading 0x.

{
  "data": "f7a6a07fa599db56fca50fa1202670b59054e7ed452ea57b3f5b43148b8bdb165beb3a4b0fd532162a1f0fd475de1a9ecd07c95186f7a0856ce1bffa45e3acc91b"
}

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

Name	Type	Description
Authorization*	String	Bearer <Client API Key>
Content-Type*	String	application/json

Body Parameters

Name	Type	Description
generateResponse*	JSON	The response body from “Create Wallets”.

Example Request

Be sure to replace the [token] with either a Client API Key or a Client Session Token.

curl --request POST \
  --url https://mpc-client.portalhq.io/v1/backup \
  --header 'Authorization: Bearer [token]' \
  --header 'Content-Type: application/json' \
  --data '{
  "generateResponse": "{\"SECP256K1\":{\"share\":\"share\",\"id\":\"shareId\"},\"ED25519\":{\"share\":\"share\",\"id\":\"shareId\"}}"
}'

Example Response

200: OK Success

{
  "SECP256K1": {
    "share": "eyJjbGl...",
    "id": "clu32l6c8008wuvz52jokyo3r"
  },
  "ED25519": {
    "share": "eyJjbGl...",
    "id": "clu32l9310087evz5u5v9k1ao"
  }
}

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

Name	Type	Description
Authorization*	String	Bearer <Client API Key>
Content-Type*	String	application/json

Body Parameters

Name	Type	Description
backupResponse*	JSON	The response body from “Back Up Wallets”.

Example Request

Be sure to replace the [token] with either a Client API Key or a Client Session Token.

curl --request POST \
  --url https://mpc-client.portalhq.io/v1/recover \
  --header 'Authorization: Bearer [token]' \
  --header 'Content-Type: application/json' \
  --data '{
  "backupResponse": "{\"SECP256K1\":{\"share\":\"share\",\"id\":\"shareId\"},\"ED25519\":{\"share\":\"share\",\"id\":\"shareId\"}}"
}'

Example Response

200: OK Success

{
  "SECP256K1": {
    "share": "eyJjbGl...",
    "id": "clu32l6c8008wuvz52jokyo3r"
  },
  "ED25519": {
    "share": "eyJjbGl...",
    "id": "clu32l9310087evz5u5v9k1ao"
  }
}