AutoCrit and Vellam are the two tools in this category that actually try to read your book, not write it for you. That makes them the closest comparison on this list, and it makes the differences worth getting right.
You can run a finished manuscript through either one. The real questions are how deep the reading goes, whether the analysis is built from your text automatically, and whether the tool works in the language you write in.
Short answer: AutoCrit is an online book editor with a large set of line-editing tools and a Story Analyzer that tracks plot and contradictions. Vellam is an analysis-first writing tool that reads the whole book chapter by chapter, builds a Story Atlas from your text, runs an AI-writing detector, and works fully in Polish, English, German and Spanish. Choose AutoCrit if you want a deep line-editing suite with a free tier and cross-book analysis in English. Choose Vellam if you want auto-built structure, an AI detector, and a tool in your own language.
What each tool is built around
AutoCrit calls itself “the smarter online book editor” and aims to make good writers great. It is an all-in-one editor with 25 or more line-editing tools (pacing, dialogue, strong writing, word choice and so on), a Story Analyzer that claims to track contradictions, timeline, foreshadowing and plot threads, and a Series Analyzer that looks across multiple books. It has a free tier. The whole product is post-draft: you upload finished text and it reports on it.
Vellam is an analysis-first writing tool. You can write the whole novel in its built-in editor, and the centre of the product is the analysis layer. It reads your manuscript chapter by chapter, builds a map of every character, location and thread automatically, checks consistency across the whole book, scores how AI-like the prose reads, and runs a rule-based prose pass at the sentence level. Its AI assistant brainstorms ideas with you but never writes the book for you.
Functional comparison
| Capability | AutoCrit | Vellam |
|---|---|---|
| Reads your whole novel chapter by chapter, remembering what came before | ||
| Tracks plot threads, timeline and contradictions across the book | ||
| Whole-book consistency check (character trait, mental state, location, plot status) | ||
| Auto-built Story Atlas (per-chapter cards generated from your text) | Vellam only | |
| Auto-extracts characters, locations and plots from each chapter | ||
| Character, location and plot heatmaps across chapters | ||
| Built-in AI-writing detector (per chapter and whole book) | Vellam only | |
| Line-level static analysis (cliches, passive, weak verbs, repetition) | ||
| Breadth of dedicated line-editing tools | ||
| Cross-book / series analysis | ||
| Long-form developmental critique of the whole book | ||
| AI assistant that brainstorms ideas (never writes prose for you) | ||
| Built-in editor you can write the whole novel in | ||
| Inline comments and shared review with reader roles | ||
| Fully localized interface and analysis (Polish, English, German, Spanish) | ||
| Free tier | ||
| One-time payment, credits never expire |
AutoCrit genuinely leads on line-tool breadth, cross-book series analysis and a free tier. Vellam leads on auto-built structure, an AI detector, localization and one-time pricing. On plot tracking and line-level checks the two tools overlap.
The things Vellam does that AutoCrit does not
It builds the Story Atlas for you, from the text
AutoCrit’s Story Analyzer reports on your plot, but you still bring the structure to it. Vellam generates the structure. After each chapter it creates per-chapter cards for every character, location and thread, pulled from what you actually wrote, and adds heatmaps that show where someone drops out of the book for a stretch. There is nothing to fill in by hand, and nothing to maintain as the draft changes. If you have ever kept a story bible up to date by hand, this is the part that removes that chore.
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. AutoCrit does not ship an AI-writing detector, so that check is one you would have to run somewhere else.
It reads the whole book in one continuous pass
Vellam reads your manuscript chapter by chapter, the way a reader does, keeping every prior chapter in mind, and from that it runs a whole-book consistency check across four specific kinds of contradiction: a character trait, a character’s state of mind, a location description, and a plot status that stops adding up. AutoCrit’s Story Analyzer claims contradiction and timeline tracking too, so this is a genuine overlap, but Vellam’s pass is anchored to the continuous read and surfaces the result in the same place you write.
It works in your language, end to end
AutoCrit operates in US and UK English variants. Vellam’s interface and its analysis are built for Polish, English, German and Spanish. If you write in any of those, that is the difference between a tool that reads your book and one that cannot.
An idea generator, not a prose generator
This is the line that matters most. 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. AutoCrit, for its part, is an editor rather than a generator, so it does not write prose for you either, but it also does not offer an idea-level brainstorming partner. If you want analysis plus a partner to think with, that gap is worth noting.
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
Vellam’s interface is fully localized in Polish, English, German and Spanish, and its analysis is built for manuscripts in those languages. AutoCrit works in English only, in US and UK variants. Some writers also report that English-only checkers flag deliberate stylistic choices as errors because they read against one narrow norm. If you write in Polish, German or Spanish, this difference is not cosmetic, and even in English a tool that understands genre intent is worth having.
You stay in control
Vellam never changes your text on its own. Its AI help is opt-in, sits in a side panel, your manuscript is never rewritten for you, and your text is not used to train any model. AutoCrit is an editor that reports on your text rather than rewriting it, which is a similar stance, but the AI-detector and the no-training guarantee are Vellam’s to make.
Choose AutoCrit if
- You want a deep, dedicated line-editing suite with 25 or more focused tools.
- You write a series and want cross-book analysis in one place.
- You write in English and want a free tier to start with.
Choose Vellam if
- You want the Story Atlas, heatmaps and entity extraction built from your text automatically, not assembled by hand.
- You want a built-in AI-writing detector for chapters and the whole book.
- You write in Polish, German, Spanish or English and want a fully localized tool.
- You want an idea-level brainstorming partner that never writes the prose for you.
- You prefer a one-time payment with credits that do not expire over a subscription.
Can you use both?
Yes. If AutoCrit’s line tools suit your editing habits, polish there, then run the manuscript through Vellam for the auto-built Story Atlas, the whole-book consistency read and the AI-writing detector before it reaches a beta reader or an editor. They overlap on plot tracking, but the structural extraction, the detector and the language support are where they diverge.
Frequently asked questions
Does AutoCrit track plot and contradictions like Vellam?
AutoCrit’s Story Analyzer claims contradiction, timeline, foreshadowing and plot-thread tracking, so on that front the two overlap. The difference is that Vellam also builds the per-chapter Story Atlas and heatmaps automatically from your text, and surfaces the consistency check inside the editor where you write.
Does Vellam have an AI-writing detector and AutoCrit does not?
Yes. Vellam scores how AI-like a chapter or the whole book reads and highlights the lowest-scoring sentences. AutoCrit does not ship an AI-writing detector, so that scan is one you would run elsewhere.
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. AutoCrit works in English only, in US and UK variants.
Is Vellam a subscription like AutoCrit?
No. Vellam is a one-time payment and the credits you buy never expire. AutoCrit is subscription-based, which is part of why some users describe it as an expensive way to get line edits.