--- updatedAt: 2026-05-20T16:41:56.000Z --- Fetch the complete documentation index at: https://docs.blockdaemon.com/llms.txt. Use this file to discover all available pages before exploring further. Append .md to any documentation page URL to get its markdown version. # Derive signing payload from unsigned transaction Create a signing payload. {`

Supported Protocols & Networks

Protocol	Network	Path Parameter
Polkadot	Mainnet	`polkadot-mainnet`
	Westend	`polkadot-westend`
	Assethub Mainnet	`polkadot-assethub-mainnet`
	Assethub Westend	`polkadot-assethub-westend`

`} # OpenAPI definition ```json { "openapi": "3.0.3", "info": { "title": "Transaction API", "version": "1.0.0", "description": "Blockdaemon transaction API to create, compile, send and verify transactions for supported blockchains.", "contact": { "name": "Blockdaemon", "email": "info@blockdaemon.com", "url": "https://blockdaemon.com" }, "x-logo": { "url": "https://storage.googleapis.com/blockdaemon-app-static-images/marketing/PNG/dark-logo.png", "altText": "Blockdaemon logo" } }, "servers": [ { "url": "https://svc.blockdaemon.com/tx/v1", "description": "Blockdaemon transaction API" } ], "security": [ { "apiKeyAuthHeader": [] }, { "bearerAuth": [] } ], "paths": { "/{blockchain_id}/derive_signing_payload": { "parameters": [ { "$ref": "#/components/parameters/blockchain_id" } ], "post": { "summary": "Derive signing payload from unsigned transaction", "description": "Create a signing payload.\n", "operationId": "TxDeriveSigningPayload", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ApiTxDeriveSigningPayloadRequest" } } } }, "responses": { "200": { "description": "A signing payload", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ApiTxDeriveSigningPayloadResponse" } } } }, "400": { "$ref": "#/components/responses/ErrorBadRequest" }, "401": { "$ref": "#/components/responses/ErrorUnauthorized" }, "429": { "$ref": "#/components/responses/ErrorTooManyRequests" }, "500": { "$ref": "#/components/responses/ErrorInternal" }, "501": { "$ref": "#/components/responses/ErrorNotImplemented" }, "503": { "$ref": "#/components/responses/ErrorServiceUnavailable" } } } } }, "components": { "securitySchemes": { "apiKeyAuthHeader": { "type": "apiKey", "in": "header", "name": "X-API-Key", "description": "Unlock higher TPS - Create your own API key in the [Blockdaemon App](https://app.blockdaemon.com).\n", "x-default": "2go1YqUcuAr4WZ2-3WgSD3c7qpatZqQuNWhTVBldKZnTSUtw" }, "bearerAuth": { "type": "http", "scheme": "bearer", "bearerFormat": "Opaque", "description": "[Legacy Auth] Unlock higher TPS - Create your own API key in the [Blockdaemon App](https://app.blockdaemon.com).\n", "x-default": "2go1YqUcuAr4WZ2-3WgSD3c7qpatZqQuNWhTVBldKZnTSUtw" } }, "parameters": { "blockchain_id": { "name": "blockchain_id", "in": "path", "required": true, "description": "Either a hyphen seperated protocol-network pair like `ethereum-mainnet` or the `chain-id`", "schema": { "type": "string", "default": "ethereum-mainnet" } } }, "responses": { "ErrorTooManyRequests": { "description": "Rate limit exceeded", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/error" }, "example": { "type": "too-many-requests", "title": "Too Many Requests", "status": 429, "detail": "Request rate limits have been exceeded. Try again after a few seconds." } } } }, "ErrorBadRequest": { "description": "Bad request", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/error" } } } }, "ErrorUnauthorized": { "description": "Invalid or expired token", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/error" }, "example": { "type": "unauthorized", "title": "Invalid Token", "status": 401 } } } }, "ErrorInternal": { "description": "An internal server error happened", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/error" }, "example": { "type": "internal-server-error", "title": "Internal Server Error", "status": 500 } } } }, "ErrorServiceUnavailable": { "description": "The resource you are trying to access is currently unavailable", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/error" }, "example": { "type": "unavailable", "title": "Unavailable", "status": 503 } } } }, "ErrorNotImplemented": { "description": "The request endpoint is not implemented", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/error" }, "example": { "type": "not-implemented", "title": "Not implemented", "status": 501 } } } } }, "schemas": { "ApiTxDeriveSigningPayloadRequest": { "anyOf": [ { "$ref": "#/components/schemas/ApiTxDeriveSigningPayloadRequestSubstrate" } ] }, "ApiTxDeriveSigningPayloadRequestSubstrate": { "title": "Api Tx Derive Signing Payload Request Substrate", "type": "object", "properties": { "unsigned_tx": { "type": "string", "description": "The hex encoded unsigned transaction", "x-oapi-codegen-extra-tags": { "validate": "required" } }, "sender_address": { "type": "string", "description": "The sender address is base58 encoding", "x-oapi-codegen-extra-tags": { "validate": "required" } }, "mortal_period": { "type": "number", "description": "The number of blocks until the transaction is expired", "default": 1000, "x-go-type": "uint64" }, "tip": { "type": "number", "x-go-type": "big.Int" }, "nonce": { "type": "number", "x-go-type": "uint64" } }, "required": [ "unsigned_tx", "sender_address" ] }, "ApiTxDeriveSigningPayloadResponse": { "anyOf": [ { "$ref": "#/components/schemas/ApiTxCreateResponseSubstrate" } ] }, "ApiTxCreateResponseSubstrate": { "title": "Api Tx Create Response Substrate", "type": "object", "properties": { "unsigned_tx": { "type": "string", "description": "The unsigned transaction." }, "signing_payload": { "type": "string", "description": "The signing payload (hex encoded)" } }, "required": [ "unsigned_tx", "signing_payload" ] }, "error": { "type": "object", "properties": { "type": { "type": "string", "description": "The HTTP error type.", "example": "bad-request" }, "code": { "type": "integer", "description": "The numeric error code.", "example": 16384 }, "title": { "type": "string", "description": "The short error description.", "example": "Invalid Address" }, "status": { "type": "integer", "description": "The HTTP status of the error.", "example": 400 }, "detail": { "type": "string", "description": "Long error description", "example": "The requested address is invalid on this protocol." } } } } } } ```