> ## Documentation Index > Fetch the complete documentation index at: https://docs.brickken.com/llms.txt > Use this file to discover all available pages before exploring further. # Prepare Transactions > **Description:** This endpoint prepares unsigned transactions for the method selected in the `method` field. For exact required and optional body fields, use the method-specific endpoints under Create Transaction. **Headers:** - `x-api-key`: `YOUR_API_KEY` for API-key auth, or `X-Payment` for x402 retries on eligible agentic methods - `Content-Type`: `application/json` **Common Request Body Parameters:** - `method` (string, required): Operation to prepare. - `chainId` (string, required): Blockchain network identifier. Hex format is recommended, for example `aa36a7` for Sepolia. - `signerAddress` (string, conditionally required): Wallet address that signs the prepared transaction. Most methods require it; `newInvest` and `claimTokens` can use `investorAddress` as the signer. - `gasLimit` (string, optional): Gas limit override. If omitted, the API estimates gas automatically. - `privateRpcUrl` (string, optional): Private RPC URL override. - `nonce` (integer, optional): Nonce override. If omitted, the API reads the pending nonce from the RPC. Prepares unsigned transactions for various blockchain operations. This endpoint supports multiple transaction methods for tokenization, STO management, token operations, and more. ## Common Parameters | Parameter | Type | Required | Description | | --------------- | ------ | ----------- | --------------------------------------------------------------------------------------------------------------------------------------- | | `chainId` | string | Yes | Blockchain network identifier (hex format) | | `method` | string | Yes | Transaction method type | | `signerAddress` | string | Conditional | Address that will sign the transaction. Most methods require it; `newInvest` and `claimTokens` can use `investorAddress` as the signer. | ## Supported Methods | Method | Description | | ---------------------- | ----------------------------------------------- | | `newTokenization` | Create a new tokenized asset. | | `mintToken` | Mint tokens to one or more investors. | | `whitelist` | Whitelist or blacklist investor wallets. | | `burnToken` | Burn tokens from the signer balance. | | `transferFrom` | Transfer tokens from an approved owner address. | | `transferTo` | Transfer tokens from the signer address. | | `approve` | Approve token spending. | | `dividendDistribution` | Distribute payment-token dividends. | | `newSto` | Create a Security Token Offering. | | `newInvest` | Prepare an STO investment. | | `claimTokens` | Claim tokens from a successful STO. | | `closeOffer` | Close an active STO. | ## Response Format The response includes the transaction details, metadata, and a unique transaction ID that must be saved for use with the `/send-transactions` endpoint. **Important:** The `txId` is NOT a blockchain transaction hash - it's an internal identifier used to link the prepared transactions with the send operation. ### Response Fields | Field | Type | Description | | -------------- | ------ | -------------------------------------------------------------------------------- | | `transactions` | array | Array of unsigned transaction objects ready for signing | | `info` | object | Metadata about the operation including emails and token symbol | | `txId` | string | Unique identifier for this transaction batch (required for `/send-transactions`) | **Next Steps:** 1. Sign each transaction in the `transactions` array 2. Submit the signed transactions along with the `txId` to `/send-transactions` ## OpenAPI ````yaml POST /prepare-transactions openapi: 3.1.0 info: title: Brickken API V2 description: >- Welcome to the Brickken API documentation. This API allows customers to create and manage tokenization processes, including creating new tokenizations, minting/burning/transferring tokens, whitelisting users, manage tokens approvals. This documentation provides detailed information on how to use the API, including the necessary endpoints, request formats, and expected responses.
**Authentication**All API requests require an API key for authentication. Include your API key in the `x-api-key` header of each request:
```
      x-api-key: YOUR_API_KEY
    ```
Ensure that your API key is kept secure and not shared publicly. A common parameter for all requests is the `signerAddress`. Such address MUST be whitelisted in our factory. To whitelist an address and/or request an API key either for sandbox/production environment please contact with: support@brickken.com. Once a `signerAddress` performs a `newTokenization` we refer to that address as the tokenizer. The tokenizer will be the only one allowed to mint such token, distribute dividends on such token and whitelist/blacklist investors of such token. Regarding actions like transferring tokens or burning tokens, the `signerAddress` can be any user and not only the tokenizer.
**Supported Networks & Addresses**
Sepolia (sandbox environment only)
```
      Chain Id: "aa36a7"
      Factory Address: "0x933ABAA95a7Fd0Bc683bDe2adB89f4C5EA64897b"
      BKN Address: "0x97a13487f889dc770Ac925Be2d3b6c833FA7746a"
      USDT Address: "0x28d2B01854D0aBec267a3DDcad9163580E6E8604"
      USDC Address: "0xb10cE8e28aEb1ae27b968Fb3bfed2FD7dd52daCb"
    ```
Base Sepolia (sandbox / testing)
```
      Chain Id: "84532" (hex "14a34")
      x402 USDC (Circle, EIP-3009): "0x036CbD53842c5426634e7929541eC2318f3dCF7e"
      ERC-8004 Identity Registry: "0x8004A818BFB912233c491871b3d84c89A494BD9e"
      ERC-8004 Reputation Registry: "0x8004B663056A597Dffe9eCcC1965A193B7388713"
    ```
Ethereum mainnet (production environment only)
```
      Chain Id: "1"
      Factory Address: "0x91af681C85Ca98Efc5D69C1B62E6F435030969Db"
      BKN Address: "0x0A638F07ACc6969abF392bB009f216D22aDEa36d"
      USDT Address: "0xdac17f958d2ee523a2206206994597c13d831ec7"
      USDC Address: "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48"
    ```
Base mainnet (production environment only)
```
      Chain Id: "2105"
      Factory Address: "0x278D7bdc2451B0Fa4087A68ce084a86cB91D4d83"
      BKN Address: "0xddB293BB5C5258F7484A94a0fBd5c8B2F6E4e376"
      USDT Address: N/A
      USDC Address: "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913"
    ```
BNB Smart Chain mainnet (production environment only)
```
      Chain Id: "38"
      Factory Address: "0xCe4529Fe88df480BD777d3e32dfD7032e6C685ff"
      BKN Address: "0x0e28bC9B03971E95acF9ae1326E51ecF9C55B498"
      USDT Address: "0x55d398326f99059fF775485246999027B3197955"
      USDC Address: "0x8AC76a51cc950d9822D68b83fE1Ad97B32Cd580d"
    ```
Avalance C Chain mainnet (production environment only)
```
      Chain Id: "a86a"
      Factory Address: "0xc6c230FA8F40022dE997727436Fae01caAbcDe61"
      BKN Address: "0xd44E4Dc8bdF7C1c62CfDBb182022097BA42Ac6bC"
      USDT Address: "0x9702230A8Ea53601f5cD2dc00fDBc13d4dF4A8c7"
      USDC Address: "0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E"
    ```
**Usage Workflow**
1. **Prepare Transactions:**- Use the `POST /prepare-transactions` endpoint with the desired method (e.g., `newTokenization`, `mintToken`, etc...) to prepare the transaction(s). - The response will include an array of unsigned transactions that needs to be signed.
**Example Of An Endpoint Response:**```json { "transactions": [ { "from": "0xSignerAddress", "to": "0xTargetAddress", "value": { "type": "BigNumber", "hex": "0x00" }, "nonce": 1, "chainId": 11155111, "data": "0x...", "type": 2, "maxPriorityFeePerGas": { "type": "BigNumber", "hex": "0x..." }, "maxFeePerGas": { "type": "BigNumber", "hex": "0x..." }, "gasLimit": { "type": "BigNumber", "hex": "0x..." } } ] } ```
2. **Sign the Transactions:**- Use your preferred method or wallet to sign the transaction data provided in the response. - Ensure that the signer address matches the `signerAddress` provided in the initial request.
**Example Of signing a transaction with typescript and `ethers-js`:**```typescript const tx = {...} // One of the object in the array returned by the `/prepare-transactions` endpoint const privateKey = process.env.PRIVATE_KEY; const wallet = new ethers.Wallet(privateKey); const signedTx = await wallet.signTransaction(tx); console.log('Signed Transaction:', signedTx); ```
**NOTE:** Be sure to have enough funds in the signer wallet to cover for the transaction cost
3. **Submit Signed Transactions:**- Use the `POST /send-transactions` endpoint to submit the signed transaction(s) along with the required parameters. - The API will process the transactions, send them to the blockchain, and update the Brickken database accordingly.
4. **Check Transaction Status:**- Use the `GET /get-transaction-status` endpoint to check the status of your transaction. - Provide either the on-chain transaction hash (`hash`) or the internal transaction ID (`txId`) to retrieve the status.
**Environments**The API is available in several environments for testing and production purposes:- Sandbox: `https://api.sandbox.brickken.com/` - Master (Production): `https://api.brickken.com/`
The API also exposes x402scan discovery facade endpoints under /x402/... The public discovery target is https://api.brickken.com, with /.well-known/x402 returning resource URLs and /openapi.json returning the generated OpenAPI 3.1 document. version: 2.0.0 servers: - url: https://api.sandbox.brickken.com description: Sandbox Environment - url: https://api.brickken.com description: Production Environment security: - apiKeyAuth: [] paths: /prepare-transactions: post: tags: - Endpoints summary: Prepare Transactions description: >- **Description:** This endpoint prepares unsigned transactions for the method selected in the `method` field. For exact required and optional body fields, use the method-specific endpoints under Create Transaction. **Headers:** - `x-api-key`: `YOUR_API_KEY` for API-key auth, or `X-Payment` for x402 retries on eligible agentic methods - `Content-Type`: `application/json` **Common Request Body Parameters:** - `method` (string, required): Operation to prepare. - `chainId` (string, required): Blockchain network identifier. Hex format is recommended, for example `aa36a7` for Sepolia. - `signerAddress` (string, conditionally required): Wallet address that signs the prepared transaction. Most methods require it; `newInvest` and `claimTokens` can use `investorAddress` as the signer. - `gasLimit` (string, optional): Gas limit override. If omitted, the API estimates gas automatically. - `privateRpcUrl` (string, optional): Private RPC URL override. - `nonce` (integer, optional): Nonce override. If omitted, the API reads the pending nonce from the RPC. requestBody: required: true content: application/json: schema: type: object properties: method: type: string example: newTokenization enum: - newTokenization - newSto - newInvest - claimTokens - mintToken - whitelist - approve - burnToken - transferFrom - transferTo - dividendDistribution - closeOffer - newTokenizedAgent - agentRegister - agentSetURI - agentSetMetadata - agentSetWallet - agentTransferOwnership - agentGiveFeedback - agentRevokeFeedback - agentAppendFeedbackResponse - agentCreateToken - agentMintToken - agentBurnToken - agentTransferToken - agentTransferFromToken - agentApproveToken description: >- The operation to be performed. Includes standard tokenization methods and x402-eligible agentic methods. Agentic methods can also be addressed through /x402/... facade endpoints, where the method is derived from the path. newTokenizedAgent remains a legacy alias for direct /prepare-transactions calls and is not listed in x402scan discovery. signerAddress: type: string description: >- Optional. Wallet address that will sign the prepared transaction. If omitted, the API uses investorAddress for this method. example: '0x742d35Cc6634C0532925a3b8D4C9db96c4b4d8b' chainId: type: string description: >- Required. Blockchain network identifier. Hex format is recommended, for example Sepolia `aa36a7`. example: aa36a7 tokenSymbol: type: string description: >- Required. Token symbol. Must be 2 to 5 uppercase letters or numbers. example: EXMPL tokenType: type: string enum: - EQUITY - DEBT - BILL_FACTORING - ICO - STABLECOIN - REVENUE_SHARE - RWA_TOKEN - PROFIT_SHARING example: EQUITY description: Optional. Token type. Defaults to EQUITY when omitted. tokenizerEmail: type: string description: >- Optional. Tokenizer email. Required for newTokenization, newSto, and closeOffer. example: tokenizer@example.com format: email acceptedCoin: type: string description: Required. Accepted payment token symbol. example: USDT amount: type: string description: >- Optional. Amount used by approve, burnToken, transferFrom, transferTo, and dividendDistribution. example: '100' endDate: type: string description: Required. STO end date. example: '2026-12-31T23:59:59.000Z' format: date-time from: type: string description: Optional. Source address required by transferFrom. example: '0x1111111111111111111111111111111111111111' pattern: ^0x[a-fA-F0-9]{40}$ gasLimit: type: string description: >- Optional. Gas limit override. If omitted, the API estimates gas automatically. example: '2000000' initialHolders: type: array description: >- Optional. Initial holders paired by index with preMints. Provide walletAddress directly, or email when a DFNS wallet can be resolved. items: type: object properties: walletAddress: type: string description: Optional. Holder wallet address. example: '0x1111111111111111111111111111111111111111' pattern: ^0x[a-fA-F0-9]{40}$ email: type: string description: >- Optional. Holder email used to resolve a DFNS wallet when walletAddress is omitted. example: holder@example.com format: email example: - walletAddress: '0x1111111111111111111111111111111111111111' investmentAmount: type: string description: Required. Payment-token amount to invest. example: '1000' investorAddress: type: string description: >- Optional. Investor wallet address. Required for newInvest and claimTokens; optional for approve payment-token owner scope. example: '0x1111111111111111111111111111111111111111' pattern: ^0x[a-fA-F0-9]{40}$ investorEmail: type: string description: >- Optional. Investor email. Required for newInvest, claimTokens, burnToken, and each whitelist/mint recipient. example: investor@example.com format: email maxInvestment: type: string description: Required. Maximum investment amount. example: '10000' maxRaiseUSD: type: string description: Required. Maximum raise amount in USD. example: '100000' minInvestment: type: string description: Required. Minimum investment amount. example: '100' minRaiseUSD: type: string description: Required. Minimum raise amount in USD. example: '10000' name: type: string description: Required. Name of the tokenized asset. example: Example Token newInvestor: type: object description: >- Optional. Default profile data used when creating missing investor users. properties: name: type: string description: Optional. Investor first name. example: John surname: type: string description: Optional. Investor surname. example: Doe middleName: type: string description: Optional. Investor middle name. example: A. secondSurname: type: string description: Optional. Investor second surname. example: Smith type: type: string description: Optional. Investor type. Defaults to INVESTOR_PERSON. example: INVESTOR_PERSON offeringName: type: string description: Required. Name of the STO offering. example: Series A paymentTokenSymbol: type: string description: >- Optional. Payment token symbol used by newInvest. If omitted, the chain default payment token is used. example: USDT preMints: type: array description: >- Optional. Pre-mint amounts. If provided, initialHolders must also be provided with the same length. items: type: object required: - amount properties: amount: type: string description: >- Required. Amount to pre-mint to the holder at the same array index. example: '1000' example: - amount: '1000' privateRpcUrl: type: string description: >- Optional. Private RPC URL override. If omitted, the API uses the configured RPC for chainId. example: https://rpc.example.com spenderAddress: type: string description: Optional. Spender address required by approve. example: '0x3333333333333333333333333333333333333333' pattern: ^0x[a-fA-F0-9]{40}$ startDate: type: string description: Required. STO start date. example: '2026-09-01T00:00:00.000Z' format: date-time supplyCap: type: string description: >- Optional. Maximum token supply. Defaults to `0` when omitted. example: '1000000' to: type: string description: >- Optional. Destination address required by transferFrom and transferTo. example: '0x2222222222222222222222222222222222222222' pattern: ^0x[a-fA-F0-9]{40}$ tokenAmount: type: string description: Required. Number of tokens offered in the STO. example: '1000' tokenizerAddress: type: string description: >- Optional. Tokenizer wallet address used by tokenization setup flows when provided. example: '0x4444444444444444444444444444444444444444' pattern: ^0x[a-fA-F0-9]{40}$ url: type: string description: >- Optional. Token documentation URL. Defaults to an empty string when omitted. example: https://example.com/token-docs userToMint: type: array minItems: 1 description: Required. Users to mint tokens to. items: type: object required: - investorEmail - amount properties: investorEmail: type: string description: Required. Recipient investor email. example: investor@example.com format: email amount: type: string description: Required. Positive whole-token amount to mint. example: '100' investorAddress: type: string description: >- Optional. Recipient wallet address. If omitted, the API attempts to create or resolve a DFNS wallet. example: '0x1111111111111111111111111111111111111111' pattern: ^0x[a-fA-F0-9]{40}$ needWhitelist: type: boolean description: >- Optional. Whether the recipient should be whitelisted before minting. Defaults to true unless explicitly false. example: true name: type: string description: >- Optional. Investor first name used when creating a new investor record. example: John surname: type: string description: >- Optional. Investor surname used when creating a new investor record. example: Doe example: - investorEmail: investor@example.com investorAddress: '0x1111111111111111111111111111111111111111' amount: '100' needWhitelist: true userToWhitelist: type: array minItems: 1 description: Required. Users to whitelist or blacklist. items: type: object required: - investorAddress - investorEmail - whitelistStatus properties: investorAddress: type: string description: Required. Investor wallet address. example: '0x1111111111111111111111111111111111111111' pattern: ^0x[a-fA-F0-9]{40}$ investorEmail: type: string description: Required. Investor email used for the investor record. example: investor@example.com format: email whitelistStatus: type: boolean description: Required. `true` to whitelist, `false` to blacklist. example: true example: - investorAddress: '0x1111111111111111111111111111111111111111' investorEmail: investor@example.com whitelistStatus: true ownerEmail: type: string example: owner@example.com description: Tokenizer owner email used by agentic methods. email: type: string example: reviewer@example.com description: Tracking email used by feedback and agent token methods. services: type: array items: type: object description: Agent service descriptors used by agentRegister. metadata: type: object description: Agent metadata stored in the registration file. aiModelName: type: string example: gpt-4o description: AI model name for agent registration or metadata updates. aiModelProvider: type: string example: openai description: AI model provider stored in the agent profile. agentUuid: type: string description: Internal tokenized agent UUID returned by agentRegister. agentId: oneOf: - type: string - type: number description: On-chain ERC-8004 agent ID. metadataKey: type: string example: modelName description: Metadata key used by agentSetMetadata. metadataValue: description: Metadata value used by agentSetMetadata. metadataEncoding: type: string enum: - string - json - hex description: Encoding mode for agentSetMetadata. newWallet: type: string description: Agent wallet assigned by agentSetWallet. signature: type: string description: Hex signature used by agentSetWallet. deadline: oneOf: - type: string - type: number description: Signature deadline used by agentSetWallet. feedbackIndex: oneOf: - type: string - type: number description: Feedback index used by reputation methods. clientAddress: type: string description: Reviewer/client address used by agentAppendFeedbackResponse. responseURI: type: string description: Off-chain response URI used by agentAppendFeedbackResponse. feedbackURI: type: string description: Off-chain feedback URI used by agentGiveFeedback. feedbackHash: type: string description: Optional 32-byte content hash for feedback. responseHash: type: string description: Optional 32-byte content hash for a feedback response. agentWallet: type: string description: Operational agent wallet used by agentCreateToken. symbol: type: string example: MAT description: Agent token symbol used by agentCreateToken. premint: type: string description: Human-readable premint amount used by agentCreateToken. decimals: type: number description: Agent token decimals. Defaults to 18. tokenAddress: type: string description: >- Deployed agent token address used by agentMintToken and agentBurnToken. x402Support: type: boolean description: >- Whether the registered agent declares x402 support in its profile. active: type: boolean description: Whether the registered agent should appear active. nonce: type: integer description: >- Optional. Nonce override. If omitted, the API reads the pending nonce from the RPC. example: 12 paymentTokenAddress: type: string description: >- Optional. Payment token contract address override. If omitted, the chain default payment token is used. example: '0x5555555555555555555555555555555555555555' pattern: ^0x[a-fA-F0-9]{40}$ required: - method - chainId example: method: newTokenization signerAddress: '0x742d35Cc6634C0532925a3b8D4C9db96c4b4d8b' chainId: aa36a7 tokenizerEmail: tokenizer@example.com name: Example Token tokenSymbol: EXMPL tokenType: EQUITY supplyCap: '1000000' url: https://example.com/token-docs preMints: - amount: '1000' initialHolders: - walletAddress: '0x1111111111111111111111111111111111111111' example: method: newTokenization signerAddress: '0x742d35Cc6634C0532925a3b8D4C9db96c4b4d8b' chainId: aa36a7 tokenizerEmail: tokenizer@example.com name: Example Token tokenSymbol: EXMPL tokenType: EQUITY supplyCap: '1000000' url: https://example.com/token-docs preMints: - amount: '1000' initialHolders: - walletAddress: '0x1111111111111111111111111111111111111111' responses: '200': description: Successful response content: application/json: schema: type: object properties: transactions: type: array description: Array of unsigned transaction objects ready for signing items: type: object properties: from: type: string description: Sender address example: '0x1234567890abcdef1234567890abcdef12345678' to: type: string description: Recipient address example: '0xabcdef1234567890abcdef1234567890abcdef12' value: type: string description: Transaction value in hex example: '0x00' nonce: type: integer description: Transaction nonce example: 3792 chainId: type: integer description: Blockchain network chain ID example: 11155111 data: type: string description: Transaction data payload example: >- 0xd362e8a70000000000000000000000000000000000000000000000000000000000000040... type: type: integer description: Transaction type (EIP-1559) example: 2 maxPriorityFeePerGas: type: string description: Maximum priority fee per gas example: '1150000' maxFeePerGas: type: string description: Maximum fee per gas example: '1156037' gasLimit: type: string description: Gas limit in hex example: '0xccef' info: type: object description: Metadata about the operation properties: tokenizerEmail: type: string description: Email of the tokenizer example: tokenizer@example.com tokenSymbol: type: string description: Symbol of the token example: EXMPL investorEmail: type: string description: Email of the investor (when applicable) example: investor@example.com txId: type: string description: >- Unique identifier for this transaction batch (required for /send-transactions). This is NOT a blockchain transaction hash. example: >- 0x46adea7bdf49c576a760102e0d6bc9ecd650b3998588cd3d7f576a7973426aad required: - transactions - txId '402': description: >- x402 payment required. The response includes a PAYMENT-REQUIRED header with a base64-encoded x402 payment request. security: - apiKeyAuth: [] - x402Payment: [] components: securitySchemes: apiKeyAuth: type: apiKey in: header name: x-api-key x402Payment: type: apiKey in: header name: X-Payment description: >- Base64-encoded x402 payment payload. Supported for x402-eligible agentic methods on /x402/... facades, /prepare-transactions, and eligible /send-transactions retries. ````