Legal · CelestLabs

Terms of Service

Last updated 21 July 2026

These terms govern your access to and use of the CelestLabs website, API and dashboard.

The service

CelestLabs provides a text-to-speech API and related tools. We may update, improve or change features over time. Beta or roadmap features are provided as-is and may change.

Accounts

You are responsible for your account, API keys and all activity under them. Keep your keys secret. You can rotate or revoke them from the dashboard.

Acceptable use

Your use must comply with our Acceptable Use Policy, which is incorporated into these terms.

Billing

Usage is pay-as-you-go, billed per character synthesised, and priced per model:

  • Feather, $1.90 per million characters, which is 0.19 cents per 1,000 characters.
  • Starling, $9.00 per million characters, which is 0.9 cents per 1,000 characters.

A free monthly allowance is included. Current prices are always listed at celestlabs.ai/pricing, and that page governs if it differs from this one. Prices may change with notice. You are responsible for charges incurred under your account.

Models and intellectual property

The CelestLabs service, site and serving stack are our property. We did not train the underlying speech models. Each of our models is built on separately licensed foundations, and those licences differ:

Feather
Built on open foundations: MIT-licensed inference code, Copyright 2025 Supertone Inc., and model weights distributed under the BigScience Open RAIL-M license. That licence carries use-based restrictions, which pass through to you via our Acceptable Use Policy.
Starling
Built on k2-fsa's OmniVoice under the Apache License 2.0, paired with separately licensed audio components. Starling is a licensed derivative, not an open-source product, and we will not describe it as one.

You own the text you submit, and you are responsible for having the rights to it. Subject to these terms and the Acceptable Use Policy, you own the audio you generate.

Built with Higgs Materials licensed from Boson AI USA, Inc., Copyright Boson AI USA, Inc., All Rights Reserved and Meta Llama 3 licensed under the Meta Llama 3 Community License, Copyright Meta Platforms, Inc., All Right Reserved.
Based on Meta Llama 3.

Disclaimers and liability

The service is provided "as is" without warranties. We do not currently publish an availability SLA. To the maximum extent permitted by law, CelestLabs is not liable for indirect or consequential damages, and our aggregate liability is limited to the amounts you paid in the preceding three months.

Termination

You may stop using the service at any time. We may suspend or terminate access for violation of these terms or the Acceptable Use Policy, or to comply with law.

Changes and contact

We may update these terms. Material changes will be posted here. Continued use constitutes acceptance. Contact: hello@celestlabs.ai.

This document is written in plain language for transparency and is not legal advice. The definitive terms are those executed with CelestLabs. Questions: hello@celestlabs.ai.