Terms of Service

Last updated: 11 October 2026

1. Scope

These terms govern the Lingolix pronunciation API, the API portal, and the related documentation (together, the "API"), provided by Lingolix UG (haftungsbeschränkt), Undinestr. 5, 12203 Berlin, Germany, registered at the Amtsgericht Charlottenburg under HRB 277621 B ("Lingolix", "we"). They apply to businesses within the meaning of § 14 of the German Civil Code (BGB), legal entities under public law, and anyone using the API for commercial or professional purposes ("Customer", "you"). Your own terms and conditions do not apply, even if we do not object to them. Individually agreed contracts, such as Enterprise agreements, take precedence over these terms.

2. Account and API keys

  • You register in the API portal and keep your account details accurate.
  • API keys are confidential. Use them on your servers only; never embed them in apps or web pages that you ship to end users. You are responsible for all usage made with your keys.
  • Tell us without delay if a key may have been compromised. We may revoke a key that is compromised or misused.

3. Plans, quotas and billing

  • Plans, included minutes, overage rates and rate limits are as shown on our pricing page at the time you subscribe. Prices are in euros plus VAT where applicable.
  • Paid plans are monthly subscriptions, billed in advance through Stripe and renewed automatically. You can cancel at any time in the API portal, effective at the end of the current billing period. Upgrades take effect immediately and are charged pro rata.
  • Usage is the duration of the audio you submit, measured to the second. Included minutes apply per billing period and do not carry over.
  • On paid plans, usage beyond the included minutes is billed in whole minutes at your plan's overage rate after the end of the billing period. Overage spend is capped per period (by default at €50); you can change or remove the cap in the API portal. Once the cap is reached, requests are rejected until the next period or until you raise the cap.
  • The Free plan is for evaluation and non-commercial use. Requests beyond its quota are rejected; there is no overage.
  • We announce price changes by email at least 30 days before they take effect. You can cancel before the change applies.

4. Your data: no storage, no training

  • We do not store the audio or text you send, and we do not use them to train or improve our models. Each request is processed in memory to compute the response and discarded once the response is sent.
  • We store usage records only: API key, time, endpoint, language, audio duration, processing time and error status. We use them for billing, quotas, abuse prevention and service quality, and keep invoices as required by law.
  • Processing takes place in Germany, on infrastructure operated by Hetzner Online GmbH.
  • Voice recordings of your users are personal data. Where you send them, we process them on your behalf as a processor under Art. 28 GDPR, on the basis of our data processing agreement, which forms part of these terms and is available from info@lingolix.com. You are responsible for the legal basis of the processing and for informing your users, including obtaining consent where required, for example for children.

5. Acceptable use

You may build your own products and services on the API. You may not:

  • resell or provide access to the API itself as a standalone service, or share your API keys;
  • circumvent quotas, rate limits or other technical restrictions;
  • reverse-engineer our models, or systematically collect API outputs to train or evaluate a competing model (benchmarking under section 7 is allowed);
  • send content you have no right to process, or use the API for unlawful purposes;
  • impair the API, for example through load tests or attacks.

6. Scores and model updates

  • Scores are automated estimates of pronunciation. They are not a certification. Do not base decisions with legal or similarly significant effects on a person, such as exam results, admissions or hiring, on API scores alone, without human review.
  • We improve our models over time, and scores for the same recording can change with a new model. Every response states the model_version that produced it.
  • Within an API version (for example /v3), we may add response fields but do not remove or change existing ones. Breaking changes come as a new API version, and we keep the previous version running for at least six months after announcing its retirement.

7. Benchmarking

You may benchmark the API and publish the results, provided you describe your method so that others can reproduce it, state the date of testing, and use the model version current at that time. We hold our own published benchmark to the same rules.

8. Availability and support

We aim for high availability but do not guarantee a particular uptime unless agreed in writing, for example in an Enterprise agreement. Maintenance may cause short interruptions; current status is shown on our status page. Support is available by email at info@lingolix.com.

9. Rights

  • The API, our models and the documentation remain ours. For the term of your subscription, you receive a non-exclusive, non-transferable right to use the API under these terms.
  • You keep all rights in your inputs. You may use the API's results freely in your products.
  • Our SDKs and benchmark code are open source under the MIT licence; that licence governs their use.

10. Liability

  • We are liable without limitation for intent and gross negligence, for injury to life, body or health, under the German Product Liability Act, and where we have given a guarantee.
  • For slight negligence, we are liable only for breach of an essential contractual obligation, meaning an obligation whose fulfilment makes proper performance of the contract possible in the first place and on which you may regularly rely. In that case our liability is limited to the damage typical for this type of contract and foreseeable at the time it was concluded.
  • Otherwise our liability is excluded. These limits also apply to our staff and agents.

11. Term and termination

Subscriptions run monthly and can be cancelled at any time to the end of the billing period. We may terminate with 30 days' notice, and immediately for good cause, such as misuse of API keys or non-payment. When the contract ends, your API keys are deactivated.

12. Changes to these terms

We announce changes to these terms by email at least six weeks before they take effect. If you do not object before then, the changes apply; we point this out in the announcement. If you object, either party may terminate the contract when the changes take effect.

13. Final provisions

German law applies, excluding the UN Convention on Contracts for the International Sale of Goods. If you are a merchant or a legal entity under public law, the exclusive place of jurisdiction is Berlin. Should any provision be invalid, the remaining provisions stay in effect. Questions: info@lingolix.com.