Harper

Offline, privacy-first grammar checker built in Rust

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Harper is an offline, open-source grammar checker built in Rust that gives context-aware English writing suggestions without sending any text to the cloud. It's aimed at writers and developers who want a fast, privacy-respecting alternative to cloud-based grammar checkers like Grammarly.

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Full match profile

Behind the summary, Matchbox keeps a richer profile of Harper - the signals our matcher actually reads to decide when to surface it. It stays private; claim the listing to see and control it.

Problem & pain-point mapping
Who we surface it to (audience fit)
What it's a strong alternative to
Trust & credibility signals

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