Start creating

Leap API

Inworld TTS APIInworld's model, through Leap

Low-cost, natural speech for characters and apps. One Leap key and one balance run it and every other model, priced per call in dollars.

Get an API keyRead the quickstart

First $5 top-up, no card fee.

  • One key for every model
  • Every call quoted first
  • A failed call costs nothing
curl https://api.tryleap.ai/v1/generations \  -H "x-api-key: $LEAP_API_KEY" \  -H "content-type: application/json" \  -H "prefer: wait=60" \  -d '{    "model": "inworld/inworld-tts",    "input": {      "text": "A warm hello from Leap"    }  }' # Video often outlasts the wait and answers "queued" or "running".# Put its "id" in GENERATION_ID and read it again until it is done:# curl https://api.tryleap.ai/v1/generations/$GENERATION_ID -H "x-api-key: $LEAP_API_KEY"

Set LEAP_API_KEY and send it. With prefer: wait=60 the answer holds the result when the call finishes within a minute; a longer one is read again by its ID.

Model ID
inworld/inworld-tts
Price per call
$0.0135 per 1,000 characters
This call
It costs $0.0135 per 1,000 characters.
First top-up
A first top-up of $5, with no fee, pays for your first calls.

The answer

What comes back

A generation. Check status first: succeeded has the file in output, a signed link that works for 24 hours, so download what you keep. failed has error and failure_cause, and costs nothing. usage.cost_usd is what the call was charged.

200 OK, trimmed
{  "id": "gen_...",  "object": "generation",  "model": "inworld/inworld-tts",  "status": "succeeded",  "output": [    {      "type": "audio",      "url": "https://api.tryleap.ai/files/..."    }  ],  "error": null,  "usage": {    "cost_usd": "..."  }}

Inputs

What Inworld TTS takes

Only text is needed; everything else has a default. The same schema is public, with no key, at api.tryleap.ai/v1/public/models/inworld/inworld-tts.

Texttext
Text, up to 2,000 characters, required
Voicevoice
Craig (en), Loretta (en), Darlene (en), Marlene (en), Hank (en), Evelyn (en), Celeste (en), Pippa (en), Tessa (en), Liam (en), Callum (en), Hamish (en), Abby (en), Graham (en), Rupert (en), Mortimer (en), Snik (en), Anjali (en), Saanvi (en), Arjun (en), Claire (en), Oliver (en), Simon (en), Elliot (en), James (en), Serena (en), Gareth (en), Vinny (en), Lauren (en), Jessica (en), Ethan (en), Tyler (en), Jason (en), Chloe (en), Veronica (en), Victoria (en), Miranda (en), Sebastian (en), Victor (en), Malcolm (en), Kayla (en), Nate (en), Jake (en), Brian (en), Amina (en), Kelsey (en), Derek (en), Grant (en), Evan (en), Alex (en), Ashley (en), Deborah (en), Dennis (en), Edward (en), Elizabeth (en), Hades (en), Julia (en), Pixie (en), Mark (en), Olivia (en), Priya (en), Ronald (en), Sarah (en), Shaun (en), Theodore (en), Timothy (en), Wendy (en), Dominus (en), Hana (en), Clive (en), Carter (en), Blake (en), Luna (en), Yichen (zh), Xiaoyin (zh), Xinyi (zh), Jing (zh), Erik (nl), Katrien (nl), Lennart (nl), Lore (nl), Alain (fr), Hélène (fr), Mathieu (fr), Étienne (fr), Johanna (de), Josef (de), Gianni (it), Orietta (it), Asuka (ja), Satoshi (ja), Hyunwoo (ko), Minji (ko), Seojun (ko), Yoona (ko), Szymon (pl), Wojciech (pl), Heitor (pt), Maitê (pt), Diego (es), Lupita (es), Miguel (es), Rafael (es), Svetlana (ru), Elena (ru), Dmitry (ru), Nikolai (ru), Riya (hi), Manoj (hi), Yael (he), Oren (he), Nour (ar), Omar (ar). Default: Craig (en)
Sample Rate Hertzsettings.sample_rate_hertz
8000, 16000, 24000, 32000, 40000, 48000. Default: 48000The sample rate in Hz for the output audio.

Pricing

Price per call

It costs $0.0135 per 1,000 characters. A first top-up of $5, with no fee, pays for your first calls. Prices are the provider's list price plus our margin (35% on most models, less on the dearest video), read from the catalog, and a quote gives the exact price of any input for free.

A free quote
curl https://api.tryleap.ai/v1/quotes \  -H "x-api-key: $LEAP_API_KEY" \  -H "content-type: application/json" \  -d '{    "model": "inworld/inworld-tts",    "input": {      "text": "A warm hello from Leap"    }  }'

How it works

How the Inworld TTS API works

Every model takes the same request, a model ID and its input, and results, prices, failures and limits work the same way for all of them.

  • Wait for it, or hear when it ends

    prefer: wait=60 holds the request until the result is ready, for up to a minute. A longer run is read again by its ID, or a signed webhook tells your server when it ends.

    prefer: wait=60 / "webhook": "https://..."

    In the docs

  • Failed calls cost nothing

    The price is held when a call starts and charged only if it succeeds. A failed or refused call comes back with its failure_cause, and the hold is released.

    "status": "failed" / "failure_cause": "provider_refused"

    In the docs

  • The price before the call

    POST /v1/quotes takes the same body as a generation and returns its exact price, with the input checked, for free. Every result carries what it was charged.

    POST https://api.tryleap.ai/v1/quotes / "cost_usd"

    In the docs

  • Rate limits

    600 requests a minute per API key and 300 per IP address. A 429 carries Retry-After with the seconds to wait.

    RateLimit-Remaining / Retry-After

    In the docs

  • Safe retries

    Send an idempotency key and a retry after a dropped connection returns the same generation instead of starting a second one.

    idempotency-key: <uuid>

    In the docs

  • Batches

    POST /v1/batches starts up to 50 calls in one request, priced and held together, so either all start or none do.

    POST https://api.tryleap.ai/v1/batches

    In the docs

MCP

Or let your agent call it.

Leap's MCP server lets Claude Code, Claude, VS Code and other MCP clients run Inworld TTS, read its inputs and fetch the result, on your balance. Signing in happens in the browser, so there is no key to paste.

Connect an agentThe agent guide
Add Leap to Claude Code
claude mcp add --transport http leap https://app.tryleap.ai/api/mcp

Claude Code signs you in through the browser the first time it calls Leap.

Teach your coding agent the Leap API
curl -fsSL https://www.tryleap.ai/install.sh | sh

Installs the Leap skill for every coding agent it finds: which endpoint to call, how to read a model's inputs, when to wait and when to poll.

Questions

Inworld TTS API questions

How much does the Inworld TTS API cost?
It costs $0.0135 per 1,000 characters. That is the provider's list price plus our margin, the same as in the studio. POST /v1/quotes prices any input for free before you run it.
Can I try the Inworld TTS API for free?
No. API keys run on paid credit, so a key's first call needs a top-up, and quotes are free. A first top-up of $5, with no fee, pays for your first calls.
Do I pay for calls that fail?
No. The price is held when a call starts and charged only if it succeeds. A call that fails, or that the model's safety filter refuses, comes back with status "failed" and a failure_cause, and the hold is released.
Is this Inworld's own API?
No. Leap is a separate service: it sends your call to Inworld's model and gives you what it makes, so you need no Inworld account. One Leap key runs Inworld TTS and every other model in the catalog, from one balance.
What are the rate limits?
600 requests a minute per API key and 300 a minute per IP address. A batch starts up to 50 calls in one request. A 429 says how long to wait in its Retry-After header.
Can an AI agent call it?
Yes. Leap's MCP server lets Claude Code, Claude, VS Code and other MCP clients find Inworld TTS, read its inputs, run it and fetch the result on your balance. The client signs you in through the browser, so there is no key to paste.

Build with Inworld TTS.

Keys run on paid credit, and the first top-up has no fee. The same key runs every model on Leap.

Get an API key