> ## Documentation Index > Fetch the complete documentation index at: https://docs.purps.lol/llms.txt > Use this file to discover all available pages before exploring further. # Build the Robinhood Chain launch > Step 2. Returns the EVM transactions to send from the creator wallet, in order: an optional swap and approval when there is a dev buy in a token pair, then the launch itself. You send these yourself (there is no relay on Robinhood Chain). Then call /robinhood/launches/{ref} with the launch transaction hash and register the strategy. ## OpenAPI ````yaml https://purps.lol/api/v1/openapi.json post /robinhood/launches/submit openapi: 3.1.0 info: title: PURPS API version: 1.0.0 description: >- Everything purps.lol can do, as JSON. Read the coin list, a coin's full page and the launchpad; launch coins on purps.lol, pump.fun and Robinhood Chain; wire an existing pump.fun coin's fees into a strategy. No key, no signup. A write is authorised by your own wallet's signature and every transaction is signed in your wallet, never by us. Every response is `{ ok: true, data }` or `{ ok: false, error }`. Cross-origin requests are allowed from any site. servers: - url: https://purps.lol/api/v1 security: [] tags: - name: Coins description: Read what the site shows. - name: Launch on purps.lol description: Launch a coin on purps.lol. Prepare, sign, submit, send, poll. - name: Launch on pump.fun description: Launch straight on pump.fun with fees wired to a strategy. - name: Launch on Robinhood Chain description: Launch through Pons on Robinhood Chain. - name: Redirect a pump.fun coin description: Point an existing pump.fun coin's creator fees at a strategy. - name: Manage a coin description: Attach a strategy to a coin launched without one. Creator-signed. - name: Transactions description: Send a signed Solana transaction through our relay and watch it land. paths: /robinhood/launches/submit: post: tags: - Launch on Robinhood Chain summary: Build the Robinhood Chain launch description: >- Step 2. Returns the EVM transactions to send from the creator wallet, in order: an optional swap and approval when there is a dev buy in a token pair, then the launch itself. You send these yourself (there is no relay on Robinhood Chain). Then call /robinhood/launches/{ref} with the launch transaction hash and register the strategy. operationId: submitRobinhoodLaunch requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/RobinhoodSubmit' responses: '200': description: The steps to send. content: application/json: schema: type: object properties: ok: type: boolean enum: - true data: $ref: '#/components/schemas/RobinhoodBuild' '400': description: Every failure carries the same envelope. content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Every failure carries the same envelope. content: application/json: schema: $ref: '#/components/schemas/Error' '403': description: Every failure carries the same envelope. content: application/json: schema: $ref: '#/components/schemas/Error' '409': description: Every failure carries the same envelope. content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Every failure carries the same envelope. content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: RobinhoodSubmit: type: object description: 'Everything in RobinhoodTerms, plus:' properties: image: type: string description: >- The coin's logo as a data URL (`data:image/png;base64,…`). PNG, JPEG, WebP or GIF, 512KB max. Send this or `imageUrl`. imageUrl: type: string description: >- A public https link to the logo instead of `image`. Fetched by us under the same size and type rules. description: type: string description: Up to 500 characters. website: type: string description: https:// link. Defaults to the coin's purps.lol page. twitter: type: string description: https:// link. telegram: type: string description: https:// link. devBuy: type: string description: Your own first buy, in ETH, as a decimal string. creatorTaxBps: type: integer description: A creator tax on every trade, basis points, up to 2000. Default 0. ts: type: integer description: The `ts` the prepare step returned. required: true signature: type: string description: >- Your wallet's signature over the prepared message. Base58 on Solana, 0x-hex on Robinhood Chain. required: true RobinhoodBuild: type: object properties: steps: type: array description: >- Transactions to send in order: `{ label, tx: { to, data, value, chainId } }`. items: type: object walletKey: type: string description: 'Keep this: the register step needs it.' feeRecipient: type: string description: The PURPS wallet the coin's fees will go to. requiredWei: type: string description: ETH the wallet needs for the whole flow, in wei. balanceWei: type: string description: What it holds now. shortByWei: type: string description: '`0` when the wallet can afford it.' imageUrl: type: string description: Where the logo was stored. pair: type: object description: The pair the coin trades in. fees: type: object description: The fee setup. Error: type: object properties: ok: type: boolean description: Always false on a failure. error: type: string description: >- A short reason in plain words: `coin not found`, `too many requests`, `invalid wallet signature`. ````