Get started in minutes with pre-built SDKs in these popular languages.

SDK for C# grammar check API
SDK for Typescript grammar check API
SDK for Javascript grammar check API
SDK for Python grammar check API
SDK for PHP grammar check API
SDK for Java grammar check API


Grammar checking

We use Artificial Intelligence to locate grammar mistakes that other checkers miss.

Contextual spelling

Typos are easy to make but can be hard to spot when they’re actually words. We look at the context to find them.


Set up your own termbase and check for unwanted terms including different forms, capitalizations, etc.

Entity Spelling

Check for incorrect spelling of millions of people, places and things.

Writing Style

Automatically check for thousands of corrections that a human copyeditor would make.


Want to go deeper? We check for many different writing-related issues such as poor readability, sentence variety issues, vague wording. We also include a contextual thesaurus. Anything in our app can be accessed through our API.

Free to try. Priced to scale.

Free Trial / Evaluation
Free(One time)
500 calls
Standard Edition
10,000 calls
Professional Edition
100,000 calls
Enterprise Edition
If you want to buy in chunks of more than 100,000 calls please contact us for pricing


Using the ProWritingAid API is simple.
After getting your license code, you can use our API in an intuitive way:

Frequently Asked Questions

Are there any free spell check APIs?

LanguageTool is an open source grammar check API. Because it's open source, you can run it on your own servers so you only have to pay for the cost of the servers. LanguageTool is based on simple rules that are written by its contributors. State-of-the-art grammar checkers use more sophisticated techniques that use machine learning and deep learning to check grammar. This means that modern grammar checkers like ProWritingAid will catch at least three times as many mistakes as a rule-based grammar checker. If you just want simple grammar checking then LanguageTool might work for you.

Why is a grammar check API important?

Grammar checking has become an expected feature wherever people write. If your application doesn't include grammar checking then it's missing a key feature that will send people towards your competitors. A grammar checker API can be used to integrate grammar checking into any application. It also allows for the automation of style guides and terminology checking.

Who is a grammar or spell check API for?

Our grammar check APIs can be used for many different uses. Here are some of the things that our current clients use our API for:

  • automated marking of essays;
  • adding grammar checking to text editors in applications;
  • improving the quality of copyediting services;
  • checking websites for grammar issues;
  • providing feedback for learners of English;
  • checking translated text for grammar mistakes;

I want to integrate real-time checking into my text editor can I do that?

Integrating real-time checking into a text editor is a common use case. Grammar checking has become and expected feature of anywhere people write. We've made it easy to integrate grammar checking into any online editor. We've build a grammar checking component that makes this easy. You should be able to integrate grammar and spellchecking into your editor in a few minutes. It's also easy to customize the look of the component so it matches your company styles. You can even add keyboard shortcuts and other customizations.

What are my billing options?

Payment will be made to us through PayPal, or alternatively you can make payments direct to us by bank transfer.

Is there a free trial?

Yes, you can try our API free. You can leverage up to 500 calls for no cost. The free trial allows you to build and test your application, and there is no time limit on the trial. Trials cannot be leveraged for commercial use.

Can you tell me how to use the API?

Of course, we'll be happy to talk to you about your use case for our API. Please Contact Us.

Are there any additional costs included to start working with the ProWritingAid API?

No, there are no setup fees of any kind.

Is there a limit to the size of text that I can analyze in one call?

Yes, each text call is limited to 100,000 characters, or about 22,000 words. If you need to analyze larger texts you will need to break them into parts and make separate calls for each part.

Where is the ProWritingAid API Documentation?

Read our API documentation which includes full documentation of all available method calls, and examples.

Are you GDPR compliant?

Yes we are. Take a look at this page for more details.

Which Languages does the ProWritingAid API have SDKs for?

We have pre-built SDKs for these computer languages, but our API just uses JSON so you can easily implement it in any language you need.

My question isn't answered here. Who do I ask?

We'll be happy to answer your question Contact Us

Start using our API

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