Writing and content decision
GPTZero
Don't rebuild: GPTZero's primary defensible value is its proprietary detection model and institutional trust/partnerships, which a lone developer or small team cannot realistically reproduce; a narrower open-source detector UI is possible but will lack the claimed accuracy, integrations, and production polish.
Visit website↗No open-source build does this yet
Nothing published replaces this one, so a replacement starts from an empty file. Here is what it would have to cover.
What a replacement has to do
- Accept pasted text or uploaded document, run an AI-detection model to compute per-document and per-sentence AI-likelihood scores, highlight suspected AI phrases and generate a downloadable report.
What it still won’t have
- Proprietary detection model and claimed industry-leading accuracy
- Built-in integrations and extensions (Chrome extension, Google Docs, Canvas, Zapier)
- Human verification / expert feedback workflows and writing-replay video features
- Scale, reliability, and dataset advantages of a production vendor
What remains hard
- Proprietary models
GPTZero uses its own proprietary model that takes hundreds of factors into consideration and boasts the highest detection accuracy in the industry
- Brand trust
Official AI detector partners of the American Federation of Teachers
First-year cost
No published price
GPTZero does not publish a price we could read, so there is nothing to compare against. What building costs is below.
Money you would actually spend
Time you would spend
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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 minimal AI-detection web service using Node.js (Express) for the API, a React UI, and Postgres for storage. In scope: (1) POST /scan that accepts text or file, (2) integrate an open-source detection model (use one of the candidate GitHub projects) to compute per-sentence and document-level AI-likelihood scores, (3) store scan metadata and results in Postgres, (4) web UI to paste text, show per-sentence highlights and a download-as-PDF report, (5) simple API GET /scans/:id to retrieve results. Out of scope: Chrome extension, Google Docs integration, human-review workflows, training new detection models. Require input validation, error handling for file uploads and model failures, and unit tests for the API and integration tests for the end-to-end scan flow.
How we checked
How the score was reached
- Pay verdict base20
- 3 cited sources+3
- Hard moats found in the evidence-3
- Evidence score20
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 · 3
Every page the run actually retrieved.
- official productGPTZero home
- official pricingGPTZero pricing
- official docsGPTZero Chrome extension
Integrity checks
What held up, and what did not.
