# harper | Automattic | Knowledge Base | Instagit

Offline, privacy-first grammar checker. Fast, open-source, Rust-powered

GitHub Stars: 13.5k

Repository: https://github.com/Automattic/harper

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## Articles

### [Overall Architecture of Automattic/harper: Modular Core, LSP, and WebAssembly Layers](/Automattic/harper/what-is-the-overall-architecture-of-automattic-harper)

Explore the modular architecture of Automattic/harper. Discover its Rust core grammar engine, LSP, and WebAssembly layers for seamless integration across editors, browsers, and desktop apps.

- Tags: architecture
- Published: 2026-08-01

### [How Automattic/harper Handles Errors: A Layered Rust Error Handling Strategy](/Automattic/harper/how-does-automattic-harper-handle-errors)

Discover how Automattic/harper leverages Rust Result and anyhow for robust error handling. Learn its layered strategy for rich diagnostics across CLI, LSP, and web interfaces.

- Tags: deep-dive
- Published: 2026-08-01

### [Main Libraries Used by Automattic/harper: A Complete Dependency Breakdown](/Automattic/harper/what-are-the-main-libraries-used-by-automattic-harper)

Explore the core libraries powering Automattic/harper. Discover its Rust and JavaScript/TypeScript dependencies for high-performance language analysis and cross-platform front-ends.

- Tags: api-reference
- Published: 2026-08-01

### [How to Set Up a Development Environment for Automattic/harper](/Automattic/harper/how-to-set-up-a-development-environment-for-automattic-harper)

Quickly set up your development environment for Automattic/harper. Run `just setup` and `just dev-component` to start coding efficiently. Get started now!

- Tags: getting-started
- Published: 2026-08-01

### [Does Automattic Harper Include Pre-Commit Hooks? A Complete Analysis](/Automattic/harper/are-there-any-pre-commit-hooks-in-automattic-harper)

Discover if Automattic Harper includes pre-commit hooks. Analyze the Automattic Harper repository and learn about its default sample files requiring manual activation.

- Tags: how-to-guide
- Published: 2026-08-01

### [Where to Find and Run Automattic/Harper Examples: A Complete Guide](/Automattic/harper/where-can-i-find-examples-of-using-automattic-harper)

Discover Automattic/harper examples in the official repository. Run browser and Node.js demos to explore the grammar-checking engine easily.

- Tags: how-to-guide
- Published: 2026-08-01

### [How to Use the Harper Command-Line Interface (CLI) for Grammar Checking](/Automattic/harper/how-to-use-the-command-line-interface-cli-for-automattic-harper)

Learn to use the Harper CLI for grammar checking directly in your terminal. Explore lint parse and spans commands with custom dialects and dictionaries.

- Tags: how-to-guide
- Published: 2026-08-01

### [Development Workflow for Automattic/harper: A Complete Contributor's Guide](/Automattic/harper/what-is-the-development-workflow-for-automattic-harper)

Understand the Automattic/harper development workflow. Learn how the just command runner orchestrates builds for Rust, WebAssembly, and JS/TS integrations in this contributor's guide.

- Tags: how-to-guide
- Published: 2026-08-01

### [Build Scripts in Automattic/harper: Complete Monorepo Build Guide](/Automattic/harper/are-there-any-build-scripts-in-automattic-harper)

Discover build scripts in Automattic/harper. This guide details npm scripts, Vite for TypeScript, and wp-scripts for WordPress plugins. Learn to build efficiently.

- Tags: how-to-guide
- Published: 2026-08-01

### [How to Build the Harper Project from Source: Complete Guide](/Automattic/harper/how-to-build-the-project-from-source-in-automattic-harper)

Learn to build the Harper project from source with our comprehensive guide. Compile the Rust core, WASM, language server, and front-ends using Rust Nodejs and pnpm.

- Tags: how-to-guide
- Published: 2026-08-01

### [Automattic Harper Dependencies: Complete Guide to the Rust Workspace Architecture](/Automattic/harper/what-are-the-dependencies-of-automattic-harper-project)

Explore Automattic Harper dependencies. Discover its Rust workspace architecture and high-performance crates like fst, pulldown-cmark, and tower-lsp-server. Learn how Harper integrates these powerful libraries.

- Tags: architecture
- Published: 2026-08-01

### [How to Find Configuration Files in Automattic/harper: A Complete Guide to Core, LSP, and Desktop Settings](/Automattic/harper/how-to-find-configuration-files-in-automattic-harper)

Master Automattic/harper configuration. Discover core, LSP, desktop, plugin, and web app settings. This guide makes finding harper config files simple and efficient.

- Tags: how-to-guide
- Published: 2026-08-01

### [Where Are the Source Files Located in the Automattic/Harper Repository?](/Automattic/harper/where-are-the-source-files-located-in-automattic-harper)

Locate source files in the Automattic/harper repository. Discover the monorepo structure and discover where Rust crates and npm packages are organized under packages/.

- Tags: how-to-guide
- Published: 2026-08-01

### [What Programming Languages Are Used in Automattic/​Harper? A Polyglot Codebase Breakdown](/Automattic/harper/what-programming-languages-are-used-in-automattic-harper)

Explore the polyglot codebase of Automattic/harper. Discover the primary languages like Rust, TypeScript, and JavaScript, along with supporting languages used in its development.

- Tags: deep-dive
- Published: 2026-08-01

### [How to Explore the Automattic/Harper Project Structure in Bash: A Comprehensive Guide](/Automattic/harper/how-to-explore-automattic-harper-project-structure-in-bash)

Explore the Automattic/harper project structure in Bash using find, tree, and git ls-tree. Map Rust crates, TypeScript packages, and the Tauri app directly from your terminal.

- Tags: how-to-guide
- Published: 2026-08-01

### [Main Directories in the Automattic Harper Repository: Complete Monorepo Guide](/Automattic/harper/what-are-the-main-directories-in-automattic-harper-repository)

Explore the main directories in the Automattic Harper monorepo. Understand the structure of this Rust-based grammar-checking ecosystem, including its core engine, WebAssembly bindings, and IDE integrations.

- Tags: how-to-guide
- Published: 2026-08-01

### [How to Manage Schema in Automattic/harper: Drizzle ORM Workflow](/Automattic/harper/how-to-manage-schema-in-automattic-harper)

Learn how to manage MySQL database schema in Automattic/harper using Drizzle ORM. Explore TypeScript table definitions and Drizzle-Kit CLI for versioned migrations.

- Tags: how-to-guide
- Published: 2026-07-27

### [Known Issues with Automattic/Harper: Core Engine Bugs and Integration Limitations](/Automattic/harper/are-there-any-known-issues-with-automattic-harper)

Discover known issues in Automattic/harper including core engine bugs like dialect defaults and coordinate translation errors. Learn about integration limitations and false positives.

- Tags: known-issues
- Published: 2026-07-27

### [Roadmap for Automattic/harper: Desktop Expansion, Cross-Platform Support, and Rule Growth](/Automattic/harper/what-is-the-roadmap-for-automattic-harper)

Explore the Automattic harper roadmap for desktop expansion on Windows/Linux, WebAssembly API growth, and rule enhancement via Weir DSL. Unlock new capabilities today.

- Tags: roadmap
- Published: 2026-07-27

### [How to Customize Automattic/harper: Rules, Configuration, and Dictionaries](/Automattic/harper/how-to-customize-automattic-harper)

Customize Automattic harper by editing the default config file, adding custom dictionaries, or authoring new rules in Rust. Learn how to tailor harper to your project.

- Tags: how-to-guide
- Published: 2026-07-27

### [Security Considerations for Automattic/harper: Privacy-First Grammar Checking](/Automattic/harper/what-are-the-security-considerations-for-automattic-harper)

Explore security considerations for Automattic harper. Learn how this privacy-first grammar checker processes text locally via WebAssembly and Rust, keeping your content secure and private.

- Tags: best-practices
- Published: 2026-07-27

### [How to Integrate Automattic/harper with Other Systems: Component Guide and API Examples](/Automattic/harper/how-to-integrate-automattic-harper-with-other-systems)

Integrate Automattic harper with other systems using harper-core, harper-wasm, harper.js, or harper-ls. This guide provides component details and API examples for seamless integration.

- Tags: how-to-guide
- Published: 2026-07-27

### [Performance Characteristics of Automattic Harper: Rust-Powered Grammar Checking Speed](/Automattic/harper/what-are-the-performance-characteristics-of-automattic-harper)

Explore Automattic Harper's blazing fast performance. Discover how its Rust core, Trie lookups, and WebAssembly deliver sub-5ms grammar checking for large documents.

- Tags: performance
- Published: 2026-07-27

### [What Database Types Does Automattic/harper Support?](/Automattic/harper/does-automattic-harper-support-specific-database-types)

Discover if Automattic/harper supports specific database types. Harper is a pure-Rust grammar-checking engine operating in-memory, with optional Node.js clients for example integrations.

- Tags: api-reference
- Published: 2026-07-27

### [How to Query Data in Automattic/harper: Core APIs and CLI Techniques](/Automattic/harper/how-to-query-data-in-automattic-harper)

Query data in Automattic/harper using core APIs and CLI techniques. Explore how Harper represents text as Documents and Tokens, with helpers to query linguistic elements efficiently.

- Tags: how-to-guide
- Published: 2026-07-27

### [Release Process for Automattic/harper: Automated CI/CD Pipeline Explained](/Automattic/harper/what-is-the-release-process-for-automattic-harper)

Discover the automated release process for Automattic/harper. Learn how GitHub Actions and `just` automate CI/CD, from versioned tags to GitHub release drafting.

- Tags: how-to-guide
- Published: 2026-07-27

### [How to Report Bugs in Automattic/harper: GitHub Issues and Discord](/Automattic/harper/how-to-report-bugs-in-automattic-harper)

Learn how to report bugs in Automattic/harper. Use GitHub Issues for tracking or Discord for quick discussion. Find detailed steps in the contributor guidelines.

- Tags: how-to-guide
- Published: 2026-07-27

### [Automattic/harper Usage Examples: How to Run the Browser and Node.js Grammar Demos](/Automattic/harper/what-are-the-usage-examples-for-automattic-harper)

Explore Automattic/harper usage examples for browser and Node.js grammar demos. Learn to implement real-time grammar checking with the harper.lint method efficiently.

- Tags: getting-started
- Published: 2026-07-27

### [How to Install Automattic/harper: A Complete Setup Guide for Every Component](/Automattic/harper/how-to-install-automattic-harper)

Install Automattic harper easily using Cargo, npm, or pre built desktop apps. Get the complete setup guide for every component here.

- Tags: how-to-guide
- Published: 2026-07-27

### [Where to Find Documentation for Automattic/harper: A Complete Guide](/Automattic/harper/where-is-the-documentation-for-automattic-harper)

Find Automattic/harper documentation within its repository. Explore Markdown files in packages/web/src/routes/docs/ and key README/ARCHITECTURE files for a complete guide.

- Tags: how-to-guide
- Published: 2026-07-27

### [Main Components of Automattic Harper: Rust Core, Language Server, and Plugin Ecosystem](/Automattic/harper/what-are-the-main-components-of-automattic-harper)

Explore the Automattic Harper components: a fast Rust core, a language server, and a flexible plugin ecosystem. Enhance your writing with this grammar-checking solution.

- Tags: architecture
- Published: 2026-07-27

### [What Programming Languages Does Automattic Harper Use? A Code-Level Breakdown](/Automattic/harper/what-programming-languages-does-automattic-harper-use)

Discover the programming languages Automattic Harper uses, from Rust in its core engine to JavaScript and TypeScript for its interfaces and plugins. Get a code-level breakdown.

- Tags: deep-dive
- Published: 2026-07-27

### [What Programming Language Is Automattic/Harper Written In?](/Automattic/harper/what-programming-language-is-automattic-harper-written-in)

Discover the programming languages behind Automattic/Harper. Explore Rust for the core engine and TypeScript/JavaScript for extensions and the UI.

- Tags: getting-started
- Published: 2026-07-26

### [Can You Fork Automattic/harper? License Terms and Complete Setup Guide](/Automattic/harper/can-i-fork-automattic-harper)

Yes, you can fork Automattic/harper under the Apache-2.0 license. Learn the complete setup guide for modifying and redistributing this grammar-checking ecosystem.

- Tags: how-to-guide
- Published: 2026-07-26

### [What Is the Purpose of the Tests Directory in Automattic/harper?](/Automattic/harper/what-is-the-purpose-of-the-tests-directory-in-automattic-harper)

Discover the purpose of the tests directory in Automattic/harper. Explore how it ensures linting accuracy, prevents regressions, and verifies cross-platform functionality.

- Tags: internals
- Published: 2026-07-26

### [Where Are the Generated Files in Automattic/harper? A Complete Guide to Build Outputs](/Automattic/harper/where-are-the-generated-files-in-automattic-harper)

Locate generated files in Automattic/harper. Discover build output locations in target and dist directories. Get your Rust and JavaScript components built efficiently.

- Tags: how-to-guide
- Published: 2026-07-26

### [Build Tools Used in Automattic/harper: Complete Polyglot Build System Guide](/Automattic/harper/what-are-the-build-tools-used-in-automattic-harper)

Discover the polyglot build tools in Automattic/harper. Learn how Just orchestrates Cargo, wasm-pack, pnpm, Vite, Tauri, and Biome for a streamlined development workflow.

- Tags: how-to-guide
- Published: 2026-07-26

### [How to Debug Automattic/harper: A Complete Guide to Troubleshooting the Grammar Checker](/Automattic/harper/how-to-debug-automattic-harper)

Debug Automattic/harper easily with RUST_BACKTRACE, RUST_LOG, CLI debug commands, component debuggers, and justfile recipes. Troubleshoot the grammar checker effectively.

- Tags: how-to-guide
- Published: 2026-07-26

### [What Is the Role of the Root Directory in Automattic/harper? The Central Hub Explained](/Automattic/harper/what-is-the-role-of-the-root-directory-in-automattic-harper)

Discover the root directory's role in Automattic/harper. It centralizes multi-language workspaces for Rust, Node.js, build commands, docs, and CI config.

- Tags: deep-dive
- Published: 2026-07-26

### [Automattic/harper Example and Demo Guide: Browser and Node.js Integration](/Automattic/harper/is-there-an-example-or-demo-for-automattic-harper)

Explore Automattic harper examples to integrate browser and Node.js. Discover the Harper lint API with this comprehensive guide and demo.

- Tags: getting-started
- Published: 2026-07-26

### [Main Modules in Automattic Harper: A Complete Architecture Breakdown](/Automattic/harper/what-are-the-main-modules-in-automattic-harper)

Explore the nine core modules of Automattic Harper. This architecture breakdown reveals the grammar-checking platform's Rust, WebAssembly, and JavaScript components.

- Tags: architecture
- Published: 2026-07-26

### [What Is the License for Automattic Harper? Apache 2.0 Terms Explained](/Automattic/harper/what-is-the-license-for-automattic-harper)

Understand the Apache 2.0 license for Automattic Harper. Learn the terms for commercial use modification and distribution of this open source code.

- Tags: api-reference
- Published: 2026-07-26

### [How to Contribute to Automattic Harper: The Complete Guide to This Rust Grammar Checker](/Automattic/harper/how-to-contribute-to-automattic-harper)

Learn how to contribute to Automattic Harper, the Rust grammar checker. Clone the repo, set up the toolchain, and submit your changes via pull request.

- Tags: how-to-guide
- Published: 2026-07-26

### [Configuration Files for Automattic/Harper: The Complete Guide to Engine, LSP, and Desktop Customization](/Automattic/harper/what-are-the-configuration-files-for-automattic-harper)

Explore Automattic/Harper configuration files for engine, LSP, and desktop customization. Master your Harper setup with this comprehensive guide to control lint rules and application settings.

- Tags: how-to-guide
- Published: 2026-07-26

### [Automattic Harper Project Structure: Monorepo Layout and Component Architecture](/Automattic/harper/how-is-the-project-structured-in-automattic-harper)

Explore the Automattic Harper project structure a Rust monorepo. Discover its core grammar engine, LSP server, CLI tool, WebAssembly bindings, and editor plugins within this detailed guide.

- Tags: architecture
- Published: 2026-07-26

### [What Scripting Languages Are Used in Automattic/harper? A Complete Guide](/Automattic/harper/what-scripting-languages-are-used-in-automattic-harper)

Discover the scripting languages in Automattic/harper: JavaScript, TypeScript, Python, Shell, and Ruby. Learn how they work with the Rust core for grammar and spell checking.

- Tags: tutorial
- Published: 2026-07-26

### [Where to Find Documentation for Automattic/harper: Complete Guide to User Guides and API References](/Automattic/harper/where-can-i-find-documentation-for-automattic-harper)

Find Automattic/harper documentation easily. Access user guides and API references directly from the repository or the Harper website. Get started with complete technical docs.

- Tags: api-reference
- Published: 2026-07-26

### [How to Run Tests in Automattic/harper: Complete Guide for Rust Core and Extensions](/Automattic/harper/how-to-run-tests-in-automattic-harper)

Master running tests in Automattic/harper with this comprehensive guide. Learn to execute Rust unit tests, WASM builds, and Playwright integration tests using the unified justfile.

- Tags: how-to-guide
- Published: 2026-07-26

### [Dependencies for Automattic/harper: Complete Cargo Workspace Guide](/Automattic/harper/what-are-the-dependencies-for-automattic-harper)

Explore the Automattic/harper Cargo workspace dependencies. Discover core libraries like fst, pulldown-cmark, and serde plus language server tools including tower-lsp-server and tokio.

- Tags: api-reference
- Published: 2026-07-26

### [What Is Automattic Harper? A Deep Dive Into the Rust-Based Grammar Engine](/Automattic/harper/what-kind-of-project-is-automattic-harper)

Explore Automattic Harper, a privacy-first Rust grammar engine compiled to WebAssembly. Discover its capabilities as a language server and editor integration for developers.

- Tags: deep-dive
- Published: 2026-07-26

### [How to Build Automattic/harper: Complete Guide to the Harper Monorepo](/Automattic/harper/how-to-build-automattic-harper)

Learn how to build Automattic/harper with our comprehensive guide. Compile Rust, generate WebAssembly, and bundle JavaScript for seamless integration.

- Tags: how-to-guide
- Published: 2026-07-26

### [Where Is the Source Code Located in Automattic/Harper? A Complete Directory Guide](/Automattic/harper/where-is-the-source-code-located-in-automattic-harper)

Discover where the source code for Automattic/harper is located. Explore the organized monorepo structure with core components in top-level directories and integrations in packages.

- Tags: tutorial
- Published: 2026-07-26

### [Main Directories in Automattic/harper: A Complete Monorepo Breakdown](/Automattic/harper/what-are-the-main-directories-in-automattic-harper)

Explore the main directories within the Automattic/harper monorepo. Discover its Rust core, WASM bindings, LSP, editor plugins, and Tauri app structure.

- Tags: architecture
- Published: 2026-07-26

### [How to Set Up Automattic/harper Locally: A Complete Development Guide](/Automattic/harper/how-to-set-up-automattic-harper-locally)

Set up Automattic/harper locally with our complete guide. Install Rust Node.js and pnpm, clone the repo, and run just setup for a seamless development environment.

- Tags: how-to-guide
- Published: 2026-07-26

### [What Is Automattic/harper? A Local-First Grammar Checker Built in Rust](/Automattic/harper/what-is-automattic-harper)

Discover Automattic harper, a local-first Rust grammar checker compiled to WebAssembly. Enjoy private linting in editors and JS without sending data externally.

- Tags: getting-started
- Published: 2026-07-26