---
title: "createNetworkTransaction"
method: POST
path: "/construction/combine"
tags: ["Cardano - Rosetta"]
---

# createNetworkTransaction

`POST /construction/combine`

Combine creates a network-specific transaction from an unsigned
transaction and an array of provided signatures.

The signed transaction returned from this method will be sent to the
`/construction/submit` endpoint by the caller.

## Request body

- ConstructionCombineRequest — ConstructionCombineRequest is the input to the `/construction/combine` endpoint. It contains the unsigned transaction blob returned by `/construction/payloads` and all required signatures to create a network transaction.
  - `network_identifier` NetworkIdentifier, required — The network_identifier specifies which network a particular object is associated with.
    - `blockchain` string, required
    - `network` string, required — If a blockchain has a specific chain-id or network identifier, it should go in this field. It is up to the client to determine which network-specific identifier is mainnet or testnet.
    - `sub_network_identifier` SubNetworkIdentifier — In blockchains with sharded state, the SubNetworkIdentifier is required to query some object on a specific shard. This identifier is optional for all non-sharded blockchains.
      - `network` string, required
      - `metadata` object
  - `unsigned_transaction` string, required
  - `signatures` Signature[], required
    - `signing_payload` SigningPayload, required — SigningPayload is signed by the client with the keypair associated with an AccountIdentifier using the specified SignatureType. SignatureType can be optionally populated if there is a restriction on the signature scheme that can be used to sign the payload.
      - `address` string — [DEPRECATED by `account_identifier` in `v1.4.4`] The network-specific address of the account that should sign the payload.
      - `account_identifier` AccountIdentifier — The account_identifier uniquely identifies an account within a network. All fields in the account_identifier are utilized to determine this uniqueness (including the metadata field, if populated).
        - `address` string, required — The address may be a cryptographic public key (or some encoding of it) or a provided username.
        - `sub_account` SubAccountIdentifier — An account may have state specific to a contract address (ERC-20 token) and/or a stake (delegated balance). The sub_account_identifier should specify which state (if applicable) an account instantiation refers to.
          - `address` string, required — The SubAccount address may be a cryptographic value or some other identifier (ex: bonded) that uniquely specifies a SubAccount.
          - `metadata` object — If the SubAccount address is not sufficient to uniquely specify a SubAccount, any other identifying information can be stored here. It is important to note that two SubAccounts with identical addresses but differing metadata will not be considered equal by clients.
        - `metadata` object — Blockchains that utilize a username model (where the address is not a derivative of a cryptographic public key) should specify the public key(s) owned by the address in metadata.
      - `hex_bytes` string, required — Hex-encoded string of the payload bytes.
      - `signature_type` Signature — recursive
    - `public_key` PublicKey, required — PublicKey contains a public key byte array for a particular CurveType encoded in hex. Note that there is no PrivateKey struct as this is NEVER the concern of an implementation.
      - `hex_bytes` string, required — Hex-encoded public key bytes in the format specified by the CurveType.
      - `curve_type` 'secp256k1' | 'secp256k1_bip340' | 'secp256r1' | 'edwards25519' | 'tweedle' | 'pallas', required — CurveType is the type of cryptographic curve associated with a PublicKey. * secp256k1: SEC compressed - `33 bytes` (https://secg.org/sec1-v2.pdf#subsubsection.2.3.3) * secp256k1_bip340: x-only - `32 bytes` (implicitly even `Y` coord. Secp256k1 compressed keys may be repurposed by dropping the first byte. (https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki#Public_Key_Generation)) * secp256r1: SEC compressed - `33 bytes` (https://secg.org/sec1-v2.pdf#subsubsection.2.3.3) * edwards25519: `y (255-bits) || x-sign-bit (1-bit)` - `32 bytes` (https://ed25519.cr.yp.to/ed25519-20110926.pdf) * tweedle: 1st pk : Fq.t (32 bytes) || 2nd pk : Fq.t (32 bytes) (https://github.com/CodaProtocol/coda/blob/develop/rfcs/0038-rosetta-construction-api.md#marshal-keys) * pallas: `x (255 bits) || y-parity-bit (1-bit) - 32 bytes` (https://github.com/zcash/pasta)
    - `signature_type` Signature, required — recursive
    - `hex_bytes` string, required

## Response `200`

Expected response to a valid request

- ConstructionCombineResponse — ConstructionCombineResponse is returned by `/construction/combine`. The network payload will be sent directly to the `construction/submit` endpoint.
  - `signed_transaction` string, required

## Other responses

- `500` — unexpected error

---

[API](https://skmtc.net/tatum/apis/blockchain-data.md) · [All operations](https://skmtc.net/tatum/apis/blockchain-data/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/tatum/blockchain-data/versions/8622ee4b8fae/schema)