Writing and content decision
SupWriter
A technical user can reproduce a useful humanizer (paste, LLM rewrite, basic heuristics, PDF upload) in about a week, but SupWriter's claimed multi-detector scoring, proprietary training samples, Chrome extension and integrations are non-trivial to match, so keeping the paid product is reasonable for full parity.
Visit website↗$9.99/mo
$120/yr
Read off the official pricing page.
$100one-off34 h to build
$15/mo3 h/mo upkeep
On cash alone, building overtakes the subscription at 3 seats.
Open-source builds that already do this
Every project below is open source and already does this job today. Fork one, self-host it, or take the parts you need - the build prompt further down assumes an empty file, and this is the shortcut past that. Licences differ; check the one on each card before you ship. All SupWriter alternatives, with the arithmetic →
What a replacement has to do
- User pastes text -> service rewrites human-like via LLM -> returns rewritten text and basic detection/score
What it still won’t have
- Proprietary humanization engine and tuned training samples
- Multi-detector, sentence-level scoring across many paid detectors (Turnitin, GPTZero, Originality.ai, Copyleaks)
- Chrome extension and MCP connector integrations out of the box
- Writing DNA / voice-matching and advanced fine-tuning sliders
- Priority support and enterprise features
What remains hard
- Proprietary data
Training samples 1.2M+ Training samples
- Brand trust
Loved by 10,000+ writers worldwide
First-year cost
Keep paying
Paying is—cheaper in year one.
On cash alone, building overtakes the subscription at 3 seats.
Money you would actually spend
Time you would spend
—
What you would spend
What we assumed
The verdict above measures whether you could build it. This one is only about money.
Runnable build prompt
Build a single-user web app (React frontend + Node.js/Express backend) deployed on a single small cloud VM or managed platform (e.g. Vercel frontend + Render/Heroku backend). Core features in scope: 1) paste or upload (PDF) text, 2) call OpenAI (or Anthropic) to rewrite/humanize text via prompt templates, 3) show original vs rewritten text and simple human-likeness score (heuristic tokens/duplication), 4) per-request credit usage and a basic account page, 5) export rewritten text and history. Out of scope: integrating paid third-party detectors (Turnitin/GPTZero/etc.), Chrome extension, multi-detector sentence-level scoring, advanced Writing DNA training. Include error handling for API failures, input validation, PDF text extraction errors, and automated unit/integration tests for backend endpoints and prompt-output parsing.
How we checked
How the score was reached
- Partly verdict base52
- An open-source build was found+5
- 5 cited sources+3
- Price verified on pricing page+3
- 3/3 assessment runs agreed+4
- Hard moats found in the evidence-3
- Evidence score64
The base comes from the verdict. Everything under it is a check that either happened or did not, and each one is a fact frozen in this record rather than a judgement made at render time - so the same evidence always produces the same number.
How scoring works →Cited sources · 5
Every page the run actually retrieved.
- official productSupWriter - Humanize AI Text & Pass AI Detectors
- official docsFeatures - AI Humanizer, Detector & Paraphraser | SupWriter
- official pricingPricing Plans - Choose Your Plan | SupWriter
- open sourcenhaouari/obsidian-textgenerator-plugin
- open sourceconorbronsdon/avoid-ai-writing
Integrity checks
What held up, and what did not.
