# Probator.ai

> Probator.ai checks writing in one editor: AI-generated text detection with its own multilingual detection model, grammar and style corrections, plagiarism checking, and hidden-character and AI-provenance-mark forensics (EU AI Act Article 50). It works in 100+ languages, issues signed and publicly verifiable certificates of analysis, and offers a REST API and a remote MCP server for AI agents. Made by Spawncore Unipessoal Lda, Portugal.

Key facts:
- AI-detection results are probabilities with reasons, not proof. The engine never calls a text "AI-generated" from one weak signal, very short texts are reported as inconclusive, and thresholds are calibrated per language for at most 1% false positives on human text. Accuracy figures are published at https://probator.ai/accuracy/.
- Probator shows hidden characters, watermarks and AI marks but never removes them.
- Plans: Free (5,000 credits a month), Starter €4.99, Pro €12.99, Team €39 for 3 seats (monthly; yearly plans are cheaper). Credits: AI detection 1 per word, grammar 1 per 3 words, plagiarism 2 per word.
- Saved documents and the account database are stored in the EU. Texts are never used to train models.

## Product
- [Home](https://probator.ai/): features, pricing and FAQ (also in Portuguese, Spanish, French, German and Italian at /pt/, /es/, /fr/, /de/, /it/)
- [Editor](https://probator.ai/app/): check a text or upload PDF, Word, Markdown, HTML or text files
- [Detection accuracy](https://probator.ai/accuracy/): test-set results of our detection model, by language
- [Verify a certificate](https://probator.ai/verify/): check that a Probator certificate is genuine and that a text matches it

## For developers and AI agents
- [API documentation](https://probator.ai/docs/api/): REST API at https://probator.ai/v1 (Pro and Team plans)
- [OpenAPI description](https://probator.ai/openapi.json)
- MCP server: https://probator.ai/mcp (Streamable HTTP; send `Authorization: Bearer <API key>`). Tools: check_ai, check_grammar, check_plagiarism, check_all, get_credits. Calls use the account's credits.
- [Full details for language models](https://probator.ai/llms-full.txt)

## Blog
- [Blog and monthly reports](https://probator.ai/blog/): anonymous monthly statistics on AI-written text, hidden characters and plagiarism
- [How Probator detects AI-written text](https://probator.ai/blog/how-probator-detects-ai-text/)
- [The EU AI Act's Article 50 for people who publish text](https://probator.ai/blog/eu-ai-act-article-50/)

## Policies
- [AI Policy](https://probator.ai/legal/ai): systems used, limits, rules for using results, EU AI Act
- [Terms of Service](https://probator.ai/legal/terms)
- [Privacy Policy](https://probator.ai/legal/privacy)