How to Build Your Own LanguageTool
Replace LanguageTool with a custom build. Free AI Grammar Checker - Your writing assistant
Build Difficulty: 5/5
Build a working replacement in a weekend with AI tools
Estimated Timeline
Based on 48 features at Weekend Project difficulty, expect about One weekend with AI-assisted development.
Recommended Tech Stack
Full-stack React framework with API routes and server components
PostgreSQL database, auth, and real-time subscriptions
Utility-first styling for rapid UI development
Key Features to Replicate
Top features across 8 categories. See all 48 features
Style(8 features)
Identifies foreign terms and suggests clearer alternatives for international audiences
Identifies and corrects improper word combinations and usage
Identifies informal words and suggests more formal alternatives
Identifies overused words and phrases, suggesting more descriptive alternatives
Advanced mode providing additional suggestions for advanced punctuation, style, and typography
+3 more in this category
Formatting(5 features)
Corrects incorrect capitalization for names, months, places, and national identities
Ensures correct placement and formatting of currency symbols
Detects inconsistent use of numeric digits versus spelled-out numbers and enforces consistent formatting
Ensures consistent spacing in numbers, percentages, and other formatted elements
Ensures correct time and date formatting for 12-hour and 24-hour formats
Grammar(5 features)
20,000+ additional checks for grammar and punctuation across multiple languages including English, German, French, Spanish, Dutch, Polish, and Portuguese
Detects errors in agreement between words, such as subject-verb agreement or plural forms
Detects and corrects grammar gaffes including incorrect subject-verb agreement, wrong plural forms, and misuse of grammatical forms
Identifies and corrects improper word order in sentences
Detects and corrects incorrect use of verb tenses and related word usage
Semantics(5 features)
Identifies and corrects double negation errors
Identifies when dates don't match the specified day of the week
Identifies unclear language patterns that should be removed or rewritten
Detects semantic errors including incorrect dates, word confusion, and double negation
Identifies commonly confused words and suggests corrections
Integration(4 features)
Works across all common browsers (Chrome, Firefox, Edge, Safari, Opera) for checking text in emails, blog posts, tweets, and any web content
Mobile application for iOS devices with text checking functionality
Native macOS application providing advanced spelling, style, and grammar suggestions across favorite Mac apps
Native Windows application providing advanced spelling, style, and grammar suggestions across favorite writing apps
Punctuation(3 features)
Identifies missing commas that would improve sentence clarity
Ensures proper use of commas, dashes, hyphens, exclamation points, and helps with complex sentence formation
Identifies unnecessary commas that should be removed
Team(3 features)
Shared dictionary feature allowing teams to add technical terms and unique phrases for consistent suggestions
Shared style guide feature for teams to enforce consistent wording and voice across all team members
Invite and manage team members by email with role-based access control
UI/UX(3 features)
Users can choose between dark and light appearance preferences for the editor
Provides a clean, focused writing environment without distractions
Quick access to synonyms by double-clicking any word in the text
Cost Calculator
Pricing data not available for LanguageTool. Check their website for current pricing.