Who wrote this: the Vellam team. We build one of the two tools compared here, so treat the Vellam column as an interested party. Everything stated about ProWritingAid below is based on what ProWritingAid publishes about itself on prowritingaid.com. Features and prices change, so confirm on the current site.
These two tools overlap on the surface and split underneath. ProWritingAid is a line-level editor: it scans your prose sentence by sentence and returns dozens of style and grammar reports. Vellam is a whole-book reader: it reads the manuscript chapter by chapter, tracks the story across the whole book, and checks whether the narrative holds together.
You can run a manuscript through either one. The real question is which level you want checked: the sentence in front of you, or the novel as a whole.
Short answer: ProWritingAid is the deepest line-level grammar and style checker in this category, and it is English-only. Vellam is an analysis-first writing tool that reads the whole book, tracks characters and plot across chapters, flags narrative contradictions, detects AI-like prose, and works natively in four languages. Both check prose at the sentence level. Choose ProWritingAid for the broadest report set in English. Choose Vellam if you need whole-book consistency, story tracking and native non-English analysis.
What each tool is built around
ProWritingAid is built around the line-level report. Its core is a set of 25 or more style and grammar reports that scan your text for grammar issues, overused words, sentence-length variety, sticky sentences, pacing, dialogue tags and more. For the whole book it sells Manuscript Analysis, paid per run with credits: one credit covers a full manuscript of up to 300,000 words, and Premium and Premium Pro get up to 40% and 65% off credits. It analyses the full manuscript and flags plot holes, setting inconsistencies and timeline errors. There is also a lifetime license option and Scrivener integration. The depth and breadth of those reports is the product, and it is genuinely the strongest in the category.
Vellam is built around whole-book analysis. You write in its built-in editor, and the centre of the tool reads your manuscript chapter by chapter, remembering what came before. From that it builds a map of every character, location and thread, checks consistency across the whole book, and tells you how AI-like the prose reads. Its AI assistant brainstorms ideas with you, but it never writes the book for you. It also ships a rule-based, sentence-level prose layer, so the two tools meet on that ground.
Functional comparison
| Capability | ProWritingAid | Vellam |
|---|---|---|
| Line-level grammar and style reports (overused words, pacing, sticky sentences) | ||
| Breadth of line-level report types (25 or more) | ||
| Rule-based static prose analysis, no credits (cliches, passive, weak verbs, repetition) | ||
| Built-in writing editor you can draft a whole novel in | ||
| Integrations (Scrivener, Word, browser) | ||
| Reads your whole novel chapter by chapter, remembering what came before | ||
| Whole-book narrative consistency check (character, mental state, location, plot) | ||
| Auto-built Story Atlas (per-chapter cards from your text) | ||
| Built-in AI-writing detector (per chapter and whole book) | ||
| Auto-extracts characters, locations and plots from each chapter | ||
| Character, location and plot heatmaps across chapters | ||
| AI critique that works on the whole book, not one scene at a time | ||
| AI brainstorms ideas with you, never writes prose for you | ||
| Inline comments and shared review with reader roles | ||
| Fully localized interface and analysis (Polish, English, German, Spanish) | ||
| One-time payment, credits never expire |
ProWritingAid leads on the breadth of line-level reports and on integrations, and it sells whole-book analysis paid per run with credits. Vellam leads on chapter-by-chapter story tracking, on contradictions pointed at the lines, and on native non-English analysis. ProWritingAid does offer a lifetime license, so the pricing row is closer than a single check suggests.
The things Vellam does that a line-level checker does not
It checks the story, not just the sentence
ProWritingAid’s Consistency report covers spelling, hyphenation, capitalization, punctuation, quotation marks, ellipses and formatting. For the story, it sells separate runs paid with credits: Manuscript Analysis flags plot holes, setting inconsistencies and timeline errors, Character Analysis spots shifts in a character’s voice, behaviour or motivation, and Plot Analysis identifies plot holes. Vellam reads the manuscript chapter by chapter, the way a reader does and flags four kinds of contradiction as you go: a character trait, a character’s state of mind, a location description, and a plot status that stops adding up, each one pointing at the lines where it happens.
It builds a Story Atlas from your text
After each chapter, Vellam generates per-chapter cards for every character, location and thread, pulled from what you actually wrote, with heatmaps that show where someone disappears for a stretch. ProWritingAid’s Character Analysis shows which characters dominate and which disappear, but it does not generate per-chapter cards for every character, location and thread, so there is nothing to compare against the story bible you would otherwise keep by hand. With Vellam, you do not keep it by hand.
It tells you how AI-like your prose reads
Vellam has a built-in AI-writing detector. Run it on a chapter or the whole book and it scores how machine-like the writing looks, with the lowest-scoring sentences highlighted. It is the same kind of scan a publisher or contest might run, so you see it first. ProWritingAid has no equivalent.
Whole-book critique is built in
ProWritingAid’s Chapter Critique looks at one chapter at a time. For the whole book it sells Manuscript, Plot and Character Analysis, each paid per run with credits. Vellam’s whole-book critique is built into the tool, without buying a separate run per pass: it holds the whole manuscript in view and produces a long-form developmental critique of the book as a whole.
An idea generator, not a prose generator
This is the part worth being clear about. Vellam’s AI is a thinking partner, not a ghostwriter. The assistant brainstorms plot, talks through a character, and points at a line that could be sharper. What it does not do is hand you finished prose to drop into your book. There is no insert button, nothing is written into your manuscript, and the whole design assumes you write every line in your own words. If you want the words in your book to be yours, that is by design here.
Built with authors and publishers, and it moves fast
Vellam is built in the open with the people who use it. There is a public feedback board where authors and publishers post requests, vote, and watch them ship, and we read and act on all of it. The roadmap is shaped by working novelists and by publishing houses at the same time, which is rare in this category, and features land quickly. The goal is the tool writers actually want, improved continuously with them.
Works in your language
ProWritingAid is only available in English, and its reports are built for English prose. Vellam’s interface is fully localized in Polish, English, German and Spanish, and its analysis is built for manuscripts in those languages. If you write in Polish, German or Spanish, that difference is not cosmetic: a line-level checker tuned for English cannot grade your sentences, and a tool with an English-only interface makes you work in a second language to edit your own book. Some writers also report that English-tuned style reports read as genre-blind, flagging conventions that are deliberate in your genre.
You stay in control
Vellam never changes your text on its own. Its AI help is opt-in, sits in a side panel, and your text is not used to train any model. ProWritingAid is also an editor rather than a generator, so on the core point of not writing your prose for you, the two tools agree. The difference is depth on either side: ProWritingAid goes deeper on the sentence, Vellam goes deeper on the book.
Choose ProWritingAid if
- You write in English and want the broadest set of line-level grammar and style reports available.
- You work in Scrivener, Word or the browser and want the checker to live inside them.
- You want a lifetime license focused on prose-level editing.
Choose Vellam if
- You want the whole book read and checked chapter by chapter, with contradictions pointed at the lines.
- You need narrative consistency, a Story Atlas, an AI-writing detector and a whole-book critique in one place.
- You write in Polish, German, Spanish or English and want a fully localized tool with native analysis.
- You prefer a one-time payment with credits that do not expire.
Can you use both?
Yes, and they fit together cleanly because they work at different levels. Draft in either editor, run ProWritingAid for a deep line-level polish on the English sentences, then run the finished manuscript through Vellam as a whole-book consistency, AI-detection and structure pass before it reaches a beta reader or an editor.
Frequently asked questions
Does ProWritingAid check whole-book story consistency?
Partly. Its Consistency report covers spelling, hyphenation, capitalization, punctuation, quotation marks, ellipses and formatting. For the story, its Manuscript Analysis, paid per run with credits, flags plot holes, setting inconsistencies and timeline errors, and Character Analysis spots shifts in voice, behaviour or motivation. Vellam’s consistency check flags specific contradictions in character traits, mental state, location descriptions and plot status chapter by chapter, pointing at the lines.
Does Vellam replace ProWritingAid’s line-level reports?
Not exactly. Vellam has a rule-based prose layer that flags cliches, passive voice, weak verbs and repetition at no credit cost, but ProWritingAid offers a broader set of line-level reports in English. They overlap on sentence-level checking and Vellam adds the whole-book layer on top.
Does Vellam work for novels written in Polish, German or Spanish?
Yes. The interface and the analysis are built for Polish, English, German and Spanish. ProWritingAid is only available in English.
Does Vellam write prose for me?
No. Its AI is an idea generator: it brainstorms and points at lines to improve, but it never hands you finished prose to paste in. You write every line in your own words.
Vellam reads your whole novel chapter by chapter, tracks every character and thread, flags narrative contradictions, and checks how AI-like the prose reads, while your text stays exactly as you wrote it.
First ~5,000 words are free.
Your text stays yours · We never train models on it