Scribens checks English grammar and spelling, including punctuation, agreement, conjugation, and word confusion.
Harper
Harper checks grammar and spelling locally on a device, with an open-source project page for writers and developers.
About Harper
Harper is a grammar and spell checker that runs on the user's device and flags capitalization errors, misspelled words, awkward phrasing and broken grammar. The site states that checks happen locally with no cloud round-trips, telemetry, or LLM in the loop.
It is offered as a language server, JavaScript library, Rust crate, browser extensions, editor extensions and native apps, including integrations for macOS, Chrome, Edge, Firefox, VS Code, Neovim, Obsidian, WordPress and Zed, with support described for US, UK, Canadian, Australian and Indian English.
Key features
- Checks spelling, grammar, capitalization and awkward phrasing on device
- Supports US, UK, Canadian, Australian and Indian English varieties
- Offers browser extensions for Chrome, Edge and Firefox
- Integrates with VS Code, Neovim, Obsidian, WordPress and Zed
- Provides language server, JavaScript library and Rust crate
- Includes macOS desktop app for system-wide text fields
Best for: Students, journalists, writers and developers who want on-device grammar and spelling checks.
Good for
- Site states all checks happen locally with no cloud round-trips or telemetry
- Source code described as available under Apache-2.0 license
- Available across browsers, editors and development tools
Harper at a glance
- Website
- writewithharper.com
- Category
- Online Tools › Text Tools
- Type
- Online tool
- Pricing
- Not confirmed. Check the site
- Platforms
- macOS, Web
- Open source
- Not stated
- Language
- English
- Good for
- Developers
- Last checked
- Oct 5, 2026 · Online when checked
- Listed
- Oct 5, 2026
Harper alternatives
Tools and sites you could use instead, ranked by how closely they match.
Grammarly's browser extension checks grammar and clarity as users write across websites.
Linkspector checks content links through a GitHub Action that runs with Reviewdog on pull requests.
Open source
24 alternatives
Harper checks grammar and spelling offline and is written in Rust, according to its repository.
Open source
24 alternatives
GetMarkdown converts PDF, Office files, HTML, images, and audio into Markdown through browser-side file processing.
LLMSTXT.NEW generates an llms.txt file for any website using a dedicated generator interface.
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Harper FAQ
How does Harper work?
It watches writing and shows an underline with suggestions when it notices a grammatical error.
Does Harper change the meaning of words?
According to the site, no. It states it will never intentionally suggest an edit that might change meaning.
Is Harper private?
The site states data never leaves the device, with no cloud round-trips, telemetry, or LLM in the loop.
Is something wrong or out of date?
Tell us and an editor will check it.
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