Head-to-Head Comparison · Alternative to Grammarly · ✍️ ai writing
Grammarly 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 Grammarly ($30/mo) across cost, hosting, data privacy, and real-world trade-offs.
Grammarly vs Harper Specification Matrix
| Dimension | Grammarly (Paid) | Harper (Replacement) |
|---|---|---|
| Monthly Price | $30 / mo | $0 / mo |
| 1-Year Cost (1 seat) | $360 / yr | $0 / yr (Save $360) |
| 1-Year Cost (5 seats) | $1,800 / yr | $0 / yr (Save $1,800) |
| 1-Year Cost (10 seats) | $3,600 / yr | $0 / yr (Save $3,600) |
| 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 Grammarly to Harper
Trade-offs, installation & data architecture
Why fork Harper instead of vibe-coding a Grammarly clone?
You can build grammar checks and rewrites, but Grammarly's moat is cross-app extensions, inline UX, enterprise controls, writing telemetry, and long-running language quality.
Grammarly vs Harper FAQ
Is Harper a good free alternative to Grammarly?+
Yes. Harper is a verified open-source (FOSS) replacement for Grammarly. A fast English grammar checker that stays on your device and mostly keeps its opinions to itself.
How much do you save switching from Grammarly to Harper?+
Grammarly costs $30/mo ($360/yr) per seat, whereas Harper is $0/mo. Switching saves $360/yr for a solo user, $1,800/yr for a 5-person team, and $3,600/yr for a 10-person team.
