# SupWriter — Humanize AI Text and Pass AI Detectors

SupWriter transforms AI-generated text into natural, human-like content that bypasses AI detectors while preserving your meaning. It also offers paraphrasing, grammar-check, and an AI-detection tool.

## What it does

- **Humanize AI text** — Rewrites AI-generated drafts to read as if written by a person. Supports tone (general, casual, formal, academic, persuasive) and purpose (general, essay, blog, email, social).
- **Paraphrase** — Rephrases text with a choice of standard, formal, casual, academic, or creative modes while keeping the meaning intact.
- **Grammar check** — Fixes grammar, spelling, and punctuation. Thorough and style modes additionally improve structure and word choice.
- **AI detector** — Classifies text as AI-generated vs human-written and reports per-detector verdicts across 12 popular AI detectors (Turnitin, GPTZero, OpenAI, Claude, Gemini, Grok, Grammarly, Crossplag, Copyleaks, QuillBot, Sapling, ZeroGPT) plus a sentence-level breakdown.

## For humans

Visit [supwriter.com](https://supwriter.com) and paste your text. Free accounts get 500-word requests; paid plans extend this up to 3,000 words and unlock 50+ languages, premium tones, and advanced humanization.

## For AI agents

SupWriter exposes three authenticated HTTP APIs that agents can call programmatically.

- `POST /api/humanize` — OpenAPI: [/.well-known/openapi/humanize.yaml](https://supwriter.com/.well-known/openapi/humanize.yaml)
- `POST /api/paraphrase` — OpenAPI: [/.well-known/openapi/paraphrase.yaml](https://supwriter.com/.well-known/openapi/paraphrase.yaml)
- `POST /api/grammar-check` — OpenAPI: [/.well-known/openapi/grammar-check.yaml](https://supwriter.com/.well-known/openapi/grammar-check.yaml)
- `POST /api/aidetect/v2` — OpenAPI: [/.well-known/openapi/ai-detector.yaml](https://supwriter.com/.well-known/openapi/ai-detector.yaml)

### Discovery

- API catalog (RFC 9727): [/.well-known/api-catalog](https://supwriter.com/.well-known/api-catalog)
- OAuth Protected Resource metadata (RFC 9728): [/.well-known/oauth-protected-resource](https://supwriter.com/.well-known/oauth-protected-resource)
- A2A agent card: [/.well-known/agent-card.json](https://supwriter.com/.well-known/agent-card.json)
- Agent skills index: [/.well-known/agent-skills/index.json](https://supwriter.com/.well-known/agent-skills/index.json)
- Planned MCP server card: [/.well-known/mcp/server-card.json](https://supwriter.com/.well-known/mcp/server-card.json)

### Authentication

All three APIs require a Supabase-issued JWT. Obtain one by authenticating against the authorization server listed in the Protected Resource Metadata, then pass it as `Authorization: Bearer <token>` or use the browser session cookie.

### Usage

Each request consumes credits: one credit per word for humanize, two credits per word for paraphrase and grammar-check. Free accounts include a limited credit allotment; paid plans include monthly refills.

## Pricing

- Free — 500 words per request, English only, basic tones.
- Basic — extended word limit, 20 languages.
- Pro — 1,500 words per request, 50+ languages, premium tones and purposes.
- Ultra — 3,000 words per request, every supported language, full feature access.

See [supwriter.com/pricing](https://supwriter.com/pricing) for current amounts.

## Contact

For API questions or integration support: support@supwriter.com.