> ## Documentation Index > Fetch the complete documentation index at: https://algorand-54fd52b3.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Text to speech > Not available on Robinhood WIF: this deployment is chat-only. This endpoint is retained for legacy documentation and must not be treated as a live WIF product. Priced per character. Charged before generation and refunded on-chain if the provider fails. ## OpenAPI ````yaml POST /v1/models/{model}/audio/speech openapi: 3.1.0 info: title: Moltworld API version: 3.0.0 description: >- Live Robinhood Chain deployment: chat requests are paid per call in WIF using x402 exact EVM/Permit2 on `eip155:4663`. Free model discovery and quotes are available. WIF is an 18-decimal ERC-20. Image, speech, video, marketplace listings and creator payouts, automatic WIF refunds/rebates, and autonomous agent mandates are not enabled. A paid chat request receives `402 Payment Required` and must be retried with a valid EVM `Payment-Signature`; the signed challenge is authoritative for amount and recipient. servers: - url: https://moltworldd.vercel.app description: Live WIF API security: [] tags: - name: Models description: Chat is the only paid modality enabled on the Robinhood WIF deployment. - name: Pricing - name: Jobs and receipts description: >- Receipt lookup and signing keys are live. Video jobs are retained for legacy deployments only. - name: Mandates description: >- WIF GET lookup verifies a pinned owner-deployed contract. Setup, funding and revocation require the owner wallet; legacy Algorand POST routes remain unavailable on WIF. - name: Marketplace description: >- When ROBINHOOD_MARKETPLACE_ENABLED=true, approved real APIs support WIF checkout, exact creator credits and wallet-authorized verified payouts. - name: Service paths: /v1/models/{model}/audio/speech: post: tags: - Models summary: Text to speech description: >- Not available on Robinhood WIF: this deployment is chat-only. This endpoint is retained for legacy documentation and must not be treated as a live WIF product. Priced per character. Charged before generation and refunded on-chain if the provider fails. parameters: - name: model in: path required: true schema: type: string description: Model slug from `GET /v1/models`, for example `gpt-4o`. requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/SpeechRequest' responses: '200': description: Success content: application/json: schema: $ref: '#/components/schemas/SpeechResponse' headers: Moltworld-Receipt: description: Signed receipt, base64url-encoded JSON. See Receipts. schema: type: string Moltworld-Request-Id: description: Request id, used to look up the receipt. schema: type: string Payment-Response: description: x402 settlement result (base64 JSON with the transaction id). schema: type: string '400': $ref: '#/components/responses/BadRequest' '402': $ref: '#/components/responses/PaymentRequired' '404': $ref: '#/components/responses/NotFound' '429': $ref: '#/components/responses/RateLimited' '502': $ref: '#/components/responses/UpstreamError' '503': $ref: '#/components/responses/Unavailable' deprecated: true security: - x402: [] - {} components: schemas: SpeechRequest: type: object properties: input: type: string description: Text to speak. voice: type: string description: One of the model's `voices`, or an ElevenLabs voice id. response_format: type: string enum: - mp3 - wav - opus - aac - flac description: One of the model's `audio_formats`. speed: type: number minimum: 0.25 maximum: 4 required: - input SpeechResponse: type: object properties: object: type: string const: audio.speech model: type: string format: type: string mime_type: type: string audio_b64: type: string description: Base64 audio. character_count: type: integer moltworld: $ref: '#/components/schemas/Meta' Meta: type: object properties: request_id: type: string price_usd_micro: type: integer description: USD quote in micro-dollars; this is not a WIF token amount. payment_asset: type: string description: Payment asset symbol, WIF on the Robinhood deployment. payment_amount_atomic: type: string pattern: ^[0-9]+$ description: Exact ERC-20 base-unit amount paid. receipt_url: type: string format: uri Error: type: object properties: error: type: object properties: code: type: string example: validation_error message: type: string required: - code - message required: - error responses: BadRequest: description: Invalid request body. Nothing was charged. content: application/json: schema: $ref: '#/components/schemas/Error' PaymentRequired: description: >- Payment required. The `Payment-Required` header holds the x402 terms for this exact request. If you sent a payment that was refused, the body explains why. headers: Payment-Required: description: >- Base64 JSON: `{ x402Version, accepts: [{ scheme, network, amount, asset, payTo, extra }] }` schema: type: string content: application/json: schema: $ref: '#/components/schemas/Error' NotFound: description: Unknown model, listing, job or receipt. content: application/json: schema: $ref: '#/components/schemas/Error' RateLimited: description: Too many requests from this IP. See `Retry-After`. content: application/json: schema: $ref: '#/components/schemas/Error' UpstreamError: description: >- The model provider failed. Chat is not charged; image, voice and video are refunded on-chain. content: application/json: schema: $ref: '#/components/schemas/Error' Unavailable: description: The model or payment verification is unavailable. Nothing was charged. content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: x402: type: apiKey in: header name: Payment-Signature description: >- x402 v2 payment payload encoded for the `Payment-Signature` header. The buyer signs the exact Robinhood Chain WIF/Permit2 requirement with an EVM wallet or compatible x402 client; do not construct it by hand. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.