GrammarBot
FreemiumGrammar checker API built for developers — fast, affordable text correction with simple REST endpoints and high free tier limits
What is GrammarBot?
GrammarBot is a grammar checker API targeted at developers who need to embed text correction into their own applications — chatbots, content management systems, forum platforms, e-learning tools, customer feedback forms, and AI writing apps. Unlike Grammarly, which focuses on end-user writing experiences, GrammarBot is API-only and does not ship with a browser extension or writing app. Developers send text to a REST endpoint, GrammarBot returns a JSON array of suggested corrections (grammar, spelling, punctuation, style) with offsets and replacement text, and the developer's app renders the suggestions however fits the UX. The platform's biggest advantages are affordability and generous free tier limits: 250 requests per day on the free tier is enough for a side project or MVP, and paid plans start at $9/month for Personal use. For comparison, Grammarly API access is enterprise-only and costs dramatically more. GrammarBot is built on a combination of proprietary models and LanguageTool under the hood, supports English (US, UK, Canada, Australia) out of the box, and handles up to 20,000 characters per request. Common use cases include adding grammar checking to no-code AI apps, moderating user-generated content, improving chatbot responses, and powering in-browser writing feedback in e-learning tools.
⚡ Quick Verdict
Developers integrating grammar checking into apps, chatbots, or content platforms without enterprise budgets
End users who want a polished writing app — use Grammarly instead
Free tier, Personal $9/mo, Business $29/mo, Enterprise $99/mo
Yes — 250 API requests per day
Affordable API with high free tier limits and simple REST integration
No end-user app — API only
Bottom line: GrammarBot scores 4.2/5 — The most developer-friendly grammar checking API for startups and indie apps that need to embed correction features.
Pricing
Free: 250 API requests per day, English only, basic grammar and spelling, no attribution required.
Personal — $9/month: 5,000 daily requests, style suggestions, priority rate limits, email support.
Business — $29/month: 25,000 daily requests, advanced style and clarity, webhook support, team dashboard.
Enterprise — $99/month: Unlimited requests, SLA guarantees, custom dictionary, on-premise deployment option, dedicated support.
Key Features
- Simple REST API with JSON responses
- Grammar, spelling, punctuation, and style checking
- Up to 20,000 characters per request
- English support for US, UK, Canada, Australia
- 250 free daily requests (no credit card)
- Webhook support on Business plan
- Custom dictionary on Enterprise plan
- On-premise deployment option for Enterprise
- Rate limits and usage dashboard
Pros & Cons
Pros
- Most affordable grammar API on the market
- Generous free tier suitable for MVPs
- Simple REST integration takes minutes
- No vendor lock-in — switch LanguageTool anytime
Cons
- API-only — no end-user app or extension
- English-focused — weaker on non-English languages
- Style suggestions less nuanced than Grammarly
FAQ
What is GrammarBot and who uses it?
GrammarBot is an API-only grammar checking service for developers who need to embed text correction into their own applications. Typical users include startups building AI writing apps, e-learning platforms adding student feedback, chatbot developers improving response quality, and content management systems checking user submissions. GrammarBot does not target end users directly — it is infrastructure that other apps build on top of.
Is GrammarBot's free tier actually free?
Yes. The free tier gives 250 API requests per day with no credit card required, supporting English grammar and spell checking. It is enough for a side project, MVP, or hobby app without any commitment. If your app grows beyond 250 daily requests, you upgrade to Personal ($9/mo) or Business ($29/mo). Most indie developers can build and launch a working app entirely on the free tier.
GrammarBot vs Grammarly API — which should developers pick?
For most developers, GrammarBot is the only practical choice. Grammarly does not offer self-serve API access — it is enterprise-only with pricing typically in the thousands per month and contract negotiations. GrammarBot provides immediate API access starting at $9/month with self-serve signup. Grammarly's suggestions are slightly more nuanced, but the access difference is enormous. For any indie or startup project, GrammarBot is the practical pick.
Does GrammarBot support non-English languages?
GrammarBot officially supports English in US, UK, Canadian, and Australian variants. Some non-English languages work on a best-effort basis via the underlying LanguageTool engine, but they are not officially supported or guaranteed. If you need serious multilingual grammar checking, LanguageTool directly or a paid multilingual service like DeepL Write is a better fit.
Can I use GrammarBot in a commercial product?
Yes. All plans including Free allow commercial use of the API in your own products. The only restriction is rate limits per tier — Free users cannot build high-traffic commercial apps without hitting the 250/day cap. Once your app exceeds free-tier limits, upgrade to Personal or Business, which allow substantially more requests with commercial rights included.
How accurate is GrammarBot compared to Grammarly?
GrammarBot catches roughly 85-90% of what Grammarly catches for basic grammar, spelling, and punctuation. Where GrammarBot trails is nuanced style suggestions — tone, clarity, engagement — which Grammarly's proprietary models have been refined on for years. For core correction (is this sentence grammatically correct?), GrammarBot is sufficient for most apps. For writing polish, Grammarly remains the gold standard.
📋 Good to know
Sign up at grammarbot.io, grab an API key, and call the REST endpoint with your text. Free tier requires no credit card.
API requests processed in transit. Text not stored long-term on Free plan. Enterprise plan offers on-premise deployment for full data isolation.
Personal ($9/mo) when you exceed 250 daily requests. Business ($29/mo) for production apps. Enterprise for SLA and on-premise needs.
Very low for developers familiar with REST APIs. Integration typically takes under an hour.