Developer API Details

Our API allows you to integrate LanguageTool into your own websites, apps, and applications.

It's easy to use: send plain text and get back a list of issues, covering spelling, grammar, and style.

LanguageTool HTTP API documentation

All our servers are hosted in Germany and are fully GDPR compliant. An on-premise version is also available.

Order monthly plans on our homepage or contact us at for larger plans and the on-premise version.

Some facts about our API plans:

  • While the maximum number of characters per request is limited to 40,000 (talk to us if you need more), the service works best for shorter texts with no more than 5,000 characters.
  • There's a limit of 100,000 characters per 60 seconds by default.
  • This API cannot be used to publicly offer a service that is a competitor to LanguageTool Plus. You are, of course, free to use it to enhance your existing apps, tools, and websites.
  • If any of these limitations pose a problem for you, just contact us at , and we'll make you an individual offer.
  • Please read our privacy policy to see how we handle your texts. In a nutshell: we don't store your texts. You are responsible for giving your users information about how their data is handled. Contact us if you're interested in an on-premise version.
  • Our plans can be canceled any month by contacting us via email. Contact us if you're interested in a long-term subscription. We offer a 20% discount for yearly upfront payments.