Instead of Harper
Harper alternatives
Harper is a free, open-source grammar checker for capitalization, spelling, awkward phrasing, and grammar errors. Its checks run locally, and its maker says suggestions arrive in under 10 ms without cloud round-trips, telemetry, or an LLM. It offers style suggestions and supports English, including British, American, Canadian, Australian, and Indian dialects. Its integrations span browser and editor extensions, native apps, a language server, and developer libraries, across platforms from Android and iOS to desktop and web.
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LanguageTool
by LanguageToolFree plan ExtensioniPhoneMac+1Multilingual grammar and tone suggestions — LanguageTool supports 31 languages and tone detection, compared with Harper’s English dialect coverage.
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Trinka
Free plan APIExtensionMac+3Academic and technical writing workflows — Trinka adds academic writing tools such as citation support, plagiarism checks, and journal finding beyond Harper’s grammar checks.
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Sapling
Free plan APIExtensionSelf-hosted+2Teams adding writing tools to applications — Sapling combines an API/SDK toolkit and team writing assistance with features such as autocomplete and AI content detection.
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Wordvice AI
Free plan ExtensionMacWeb+1Students and academic document proofreading — Wordvice AI adds academic-oriented proofreading, paraphrasing, translation, and plagiarism checking to grammar and style tools.
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ProWritingAid
by ProWritingAidFree plan ExtensionBrowser-based editing in short passages — ProWritingAid limits free suggestions to 500 words at a time, while Harper is free without a stated word limit.
Free plan · paid from $10/mo (annual) Visit site - 8
Grammalecte
Free plan Open source APIExtensionLinux+3 - 9
Microsoft Editor
Free plan ExtensionMacWeb+1 - 10
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Linguix
Free plan AndroidAPIExtension+2 - 13
Duden-Mentor
Free plan APIExtensionMac+2 - 14
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iGrammar
Free plan AndroidAPIExtension+3 - 17
Grammar Guru
Free plan ExtensionLinuxMac+2 - 18
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Lexicon
Free plan ExtensionLinuxMac+1 - 20
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GrammarCheck.ai
Free plan AndroidAPIExtension+3 - 24
Corrector.app
Free plan AndroidExtensioniPhone+2 - 25
Gramma
Free plan APILinuxMac+3
Harper may be less suitable when you need writing support beyond English or specific features such as tone detection, paraphrasing, academic tools, or a team-oriented API toolkit. LanguageTool and Grammarly offer much broader language coverage; Trinka and Wordvice AI add specialized writing tools, while Sapling centers on application integrations and team assistance. Check each product’s platforms and free-plan scope against your needs, and weigh paid pricing where it is provided. Harper costs nothing, but its Gmail checking requires disabling Gmail’s built-in grammar checker, and its desktop apps include beta availability details.