Compare AmberPen
We ran every checker below over the same public corpora — 754 JFLEG development sentences and 6,845 CWEB test sentences — and scored the outputs with the same local tools. Each page covers one competitor in full: quality, speed, price, and the cases where the other tool is the better choice.
| Comparison | Where it stands | JFLEG GLEU |
|---|---|---|
| AmberPen | Neural proofreading with structured edits, explanations, and multilingual support. | 0.561 |
| AmberPen vs Sapling | Neural correction API with a similar edit-based contract, at roughly three times the price. | 0.470 |
| AmberPen vs GrammarBot Neural | The closest neural competitor on quality, with markedly higher latency at p50. | 0.413 |
| AmberPen vs Harper | Free, open-source, and fully local. Fastest of the set, and the lowest benchmark quality. | 0.344 |
| AmberPen vs LanguageTool | Mature rule-based checker. Precise on the patterns it encodes, blind to errors no rule anticipates. | 0.307 |
See Benchmarks & performance for the complete methodology and the raw numbers behind every page here.
Still shortlisting? The grammar checker API comparison reviews seven options side by side, and how grammar correction is measured explains what these scores do and do not prove.