Head-to-Head Comparison · Alternative to LanguageTool · ✍️ ai writing
LanguageTool vs Harper
A fast English grammar checker that stays on your device and mostly keeps its opinions to itself. Here is how Harper ($0/mo open source) stacks up against LanguageTool ($5.47/mo) across cost, hosting, data privacy, and real-world trade-offs.
LanguageTool vs Harper Specification Matrix
| Dimension | LanguageTool (Paid) | Harper (Replacement) |
|---|---|---|
| Monthly Price | $5.47 / mo | $0 / mo |
| 1-Year Cost (1 seat) | $66 / yr | $0 / yr (Save $66) |
| 1-Year Cost (5 seats) | $328 / yr | $0 / yr (Save $328) |
| 1-Year Cost (10 seats) | $656 / yr | $0 / yr (Save $656) |
| Source & License | Proprietary SaaS | open source |
| Where It Runs | Vendor Cloud | Self-hosted or Cloud |
| Platforms | Web / Cloud | desktopmobileextensionone-click install |
| GitHub Stars | — | ★ 14k (active aug 2026) |
Deep Dive: Switching from LanguageTool to Harper
Trade-offs, installation & data architecture
Why fork Harper instead of vibe-coding a LanguageTool clone?
Because the core engine is open source, a technical user can run the grammar checker locally or self-host the server for many use cases.
LanguageTool vs Harper FAQ
Is Harper a good free alternative to LanguageTool?+
Yes. Harper is a verified open-source (FOSS) replacement for LanguageTool. A fast English grammar checker that stays on your device and mostly keeps its opinions to itself.
How much do you save switching from LanguageTool to Harper?+
LanguageTool costs $5.47/mo ($66/yr) per seat, whereas Harper is $0/mo. Switching saves $66/yr for a solo user, $328/yr for a 5-person team, and $656/yr for a 10-person team.
