Level Checker API Documentation

The Virtual Writing Tutor provides web services for checking levels. Our level checker API allows for the integration of essay proofreading and scoring services into any website or application. This page documents the level check API.

Please note that we recommend that automatically generated feedback and scores be used to support learning and not for high stakes decisions unless reviewed and validated by a human teacher.

This webpage is intended for programmers only. English language learners should go to the grammar checker page to login for a free member's account.

Need help with installation? Contact us for an affordable installation service.

We require users to register for an API key*. To generate an API key*, fill in the form below and click the "Generate" button.

*Note: If you already have a essay checker or grammar checker API key, then there is no need to generate another. We recommend that you use same API key.

https://console.virtualwritingtutor.com/console/level/check-levelContent-Type : application/json

vwtApiKey : xxxxxxxxxx*

*(This is the generated API key)
POST { "text" : "I make a lot of mistake that negatively effect my writing." } { jsonrpc": "2.0", "status": true, "result": { "grammar_check": { "error_grammar_count_total": 2, "error_grammar_percent": "19%", "check_grammar_feedback": [ { "context": "I make a lot of mistake that negatively effect my writing.", "error_grammar": "mistake", "feedback_grammar": "Use a plural when you mean more than one mistake. Revise: \"mistakes\" (Plural needed)", "marked_text": "I make a lot of <u><font color ='#ff0000'>mistake</font></u> that negatively effect my writing.", "error_category": "Plural error", "feedback_grammar_suggestion": [ "mistakes" ] }, { "context": "I make a lot of mistake that negatively effect my writing.", "error_grammar": "effect", "feedback_grammar": "You have a problem with your verb agreement. The pronoun \"that\" must be used with a third-person verb: \"effects\". (VA201)", "marked_text": "...I make a lot of mistake that negatively <u><font color ='#ff0000'>effect</font></u> my writing.", "error_category": "Verb agreement error", "feedback_grammar_suggestion": [ "effects" ] } ] }, "level_error_profile": "c2", "level_error_density": "a2", "text": "I make a lot of mistake that negatively effect my writing.", "pos_text": "I <span class=\"verb\" title=\"VERB\">make</span> a <span class=\"noun\" title=\"NOUN\">lot</span> of <span class=\"noun\" title=\"NOUN\">mistake</span> that <span class=\"adv\" title=\"ADV\">negatively</span> <span class=\"verb\" title=\"VERB\">effect</span> my <span class=\"verb\" title=\"VERB\">writing</span> .", "level_error_vocabulary": "b2", "level": "a2", "cefr_words": { "A1": "make, write, a lot", "A2": "mistake", "B1": "that", "B2": "negatively", "C1": "", "C2": "" } } }

If an error occurs, you'll get a response like this:

{ "status": "401", "message": "unauthorized, You may need an valid api key to get access or may renew your subscription plan." }

The usual cause is a bad API key or the grammar checker is updating and so unavailable for 30 seconds while the system loads the new rules.

Screenshots (Postman)


*(xxxxxxxx) is your API key
N/AGET { "jsonrpc": "2.0", "status": true, "result": [ { "client_name": "xxx", "client_email": "xxx", "api_key": "xxxxxxxx", "used_essay_hits": 1, "total_essay_hits": 100, "remaining_essay_hits": 99, "used_grammar_hits": 100, "total_grammar_hits": 100, "remaining_grammar_hits": 0 } ] }

For Step 1 to Step 3, the system will not register any hits, so your account will not be debited any calls while them. For each single call during Step 4 (which generates feedback), your account will be debited 1 call because the system registers 1 hit each time.

See below for the price list

No.Package NamePriceDuration(in months)Total hits

Want free calls?

Link to the VirtualWritingTutor on a webpage or blog with the keyword "grammar check" and contact us with your API username and a link to the page with the published link. We also offer free calls when you promote the VirtualWritingTutor on social media. Just contact us with the link(s).


  • The API user will publicly display a hyperlink to VirtualWritingTutor.com on the website where the API is used, crediting the Virtual Writing Tutor.
  • Bokomaru Publications, the owner and operator of VirtualWritingTutor.com, will endeavor to maintain uninterrupted service for the duration of the paid subscription to the API, but the API user acknowledges that Bokomaru Publications will not be held liable for interruptions of service.

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