Grammarly and ProWritingAid are the two names every writer hears first, and for everyday prose they are close competitors. For a novel, they are not — one of them was shaped around long-form fiction and the other wasn't. Here is the comparison from a novelist's seat, with a disclosure: Authors Starport makes an editing suite that competes with both, so treat our view of where they stop as a maker's case.
| Category | ProWritingAid | Grammarly |
|---|---|---|
| Built for | Long-form writing, with fiction reports | Everyday prose — email, documents, web |
| Grammar and spelling | Strong | Strong, and the fastest in real time |
| Style reports | A large set: overused words, echoes, sticky sentences, pacing, dialogue tags, readability, sentence variety | Clarity, conciseness, engagement and delivery suggestions; tone detection |
| Whole-manuscript view | Yes — reports summarise across the document | Sentence-by-sentence as you type; long documents get heavy |
| Fiction awareness | Dialogue-tag, pacing and cliché reports; some genre settings | Minimal — fragments, dialect and deliberate rule-breaking are flagged as errors |
| Voice | General style rules; you can tune reports | Edits toward standard, confident prose — the opposite of a distinctive voice |
| Where it runs | Word, Google Docs, Scrivener, browser, desktop app | Browser extension, desktop and mobile apps, Word add-in |
| Story and structure | None | None |
| Makes the edits? | One-click per suggestion, AI rewrites; the manuscript edit is still yours | One-click per suggestion, generative rewrites; same |
| Pricing | Both have a free tier and paid plans set by the vendor, which change. Check each site; we don't quote rivals' prices. | |
Do you write in Scrivener? ProWritingAid, and it isn't close. Is most of your writing email, marketing and blurbs? Grammarly will serve you better day to day. Do you have a distinctive voice? Be careful with both — accepting suggestions wholesale across a manuscript sands it off — but ProWritingAid's reports are easier to read as information rather than instructions.
And the question neither answers: does the story work? Both tools are silent on structure, stakes, arcs and pacing at the chapter level. A manuscript can pass both clean and still lose readers by chapter three. That read is a developmental edit — from a human, or from a story-level tool such as Authors Starport's Developmental Critique.
Starport isn't a typing assistant and doesn't try to be; keep Grammarly or ProWritingAid for that. It reads a finished draft whole and does the jobs the two of them leave to you: the structural critique, a Style Sheet reverse-engineered from your own prose, a line edit rendered as tracked changes in your Word file against that sheet, a Scene Map, and an Instant Score. If you're weighing the two grammar tools because the book itself needs help, the free Reader-Ready Scorecard is the cheaper first step — and it'll tell you which problem you actually have. See also our Grammarly alternatives for novelists shortlist.
Most writing tools give you an AI read of your pages and nothing else. Authors Starport is a full editing suite — developmental critique, a line edit delivered as tracked changes, a style sheet built from your own prose, a scene map and an instant score — and every one of those tools is grounded in what real readers actually respond to. Behind them sit 694,681 hook mentions extracted from real reader reviews, 137,874 book blurbs analysed for hook, stakes and tone, and 4,293 reader personas built from that data. On this site, since June 2026, authors have uploaded 74 manuscripts and run 214 completed critiques and edits plus 40 free Scorecards.
Compared with ProWritingAid and Grammarly, which check prose against a general rulebook, Starport builds the rulebook from your manuscript, grounds its judgement in what real readers respond to, and returns the edit done rather than flagged.
Counted from our own databases on 21 August 2026. We update these figures when we re-count; we don't round them up.
The Reader-Ready Scorecard grades your full manuscript on nine craft metrics, benchmarks it against professionally-edited books, and tells you exactly what to fix first. Free, in minutes.
Get your free Reader-Ready Scorecard →ProWritingAid, for the manuscript itself: its reports run across a whole document, it has fiction-specific checks, and it works inside Scrivener and Word. Grammarly is the better real-time assistant for the everyday writing around your book. Neither reads story structure or models your voice.
Partly. It catches typos and obvious grammar slips, but it edits toward standard, confident prose and flags deliberate fragments, dialect and rule-breaking dialogue as errors. Accepting its suggestions wholesale across a manuscript flattens voice. Use it for the writing around your book, and be selective on the book itself.
You can, though they overlap heavily on grammar and many writers find two real-time checkers exhausting. A more useful pairing is one grammar tool plus something that does a different job — a developmental read, or a line editor that works from your own style sheet, such as Authors Starport.
Both have free tiers and paid plans that the vendors change regularly, so check each site for current pricing rather than trusting a comparison page. Authors Starport's pricing is on our plans page and is pay-as-you-go by tool.