Submit blockchain transactions

post

https://api.mevx.io/swap/api/v1/transaction

Submit pre-signed transactions, or build and submit a swap in one request.

Recommended: `type: "submit"`

Build with /swap/api/v1/transaction/build, sign locally, then send chain, exchange, type: "submit", and a non-empty signedTransactions array. The response is always {"result": ["signature-or-hash"]}.

Optional: `type: "buildAndSubmit"`

Send buildTransactionData with a private key to let the service build, sign, and submit. This mode is not available for Jupiter and is not recommended when client-side signing is possible.

Multiple transactions

Normal RPC mode (antiMev: false): transactions are broadcast independently; submission is not atomic and array order is not a landing guarantee.
Solana with Jito: multiple transactions are sent as one Jito bundle.
Solana with NextBlock, Temporal, CBase, ZeroSlot, or bloXroute: send exactly one transaction.
BSC with bloXroute: multiple transactions are sent in one bloXroute bundle request.
Jupiter: send exactly one transaction plus the unchanged requestId and lastValidBlockHeight returned by the build endpoint.

MEV providers can reject or drop a bundle. A successful HTTP response means the submission was accepted by the configured submission path; use the status endpoint to determine on-chain outcome.

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Body Params

The HTTP body is encrypted text, but the plaintext before encryption is a JSON object.

Submit signed transactions — recommended

Decrypted JSON field	Required	Description
`chain`	Yes	`sol`, `eth`, `bsc`, or `base`
`exchange`	Yes	DEX used to build the transaction, such as `raydium`, `jupiter`, or `uniswap`
`type`	Yes	Set to `submit`
`signedTransactions`	Yes	Non-empty array of signed serialized transactions
`setting`	No	Supports `antiMev`, `antiMevProvider`, `mevPriorityFee`, `mevTip`, `priorityFee`, and `wrappedNative`
`requestId`	Jupiter only	Unchanged value returned by the build endpoint
`lastValidBlockHeight`	Jupiter only	Unchanged value returned by the build endpoint

setting options

Field	Type/default	Description
`antiMev`	boolean, `false`	Enable protected submission
`antiMevProvider`	enum, optional	Choose from the provider table below; omit to use the configured chain default
`mevPriorityFee`	numeric string	Provider priority fee in the chain native token
`mevTip`	numeric string	Provider tip in the chain native token
`priorityFee`	numeric string	Standard priority fee in the chain native token
`wrappedNative`	boolean, `false`	Request wrapped-native-token behavior where supported

antiMevProvider options

Set setting.antiMev to true, then optionally select one of these exact values:

Chain	`antiMevProvider` values
Solana	`jito`, `nextblock`, `temporal`, `cbase`, `zeroslot`, `bloxroute`
BSC	`bloxroute`
Ethereum	Not supported
Base	Not supported

Jupiter ignores anti-MEV settings because it handles landing.

Plaintext example:

{
  "chain": "sol",
  "exchange": "raydium",
  "type": "submit",
  "signedTransactions": ["BASE64_SIGNED_TRANSACTION"],
  "setting": {
    "antiMev": true,
    "antiMevProvider": "jito"
  }
}

Build and submit in one request

Set type to buildAndSubmit and replace signedTransactions with buildTransactionData. The nested object uses the build fields documented on the build endpoint and must include wallets.privateKey. Jupiter does not support this mode.

Stringify the plaintext JSON, encrypt it as AES-256-GCM using 12-byte nonce || ciphertext || 16-byte tag, encode it with unpadded Base64URL, and send that string as this text/plain body. The ReadMe Node.js sample performs the complete transformation.

Responses

Submit signed transactions — recommended

setting options

antiMevProvider options

Build and submit in one request

200Transaction submitted successfully to the blockchain

400Bad request - Invalid transaction parameters

401Unauthorized - missing, invalid, or expired API key

429Rate limit exceeded - too many requests

500Internal server error - unexpected system error