Changelog
Store listing polish. Still a classifier for Claude-like writing until a public detector exists.
Launched. Paste text or upload a document to see whether writing looks like Claude.

Anthropic Claude Writing Watermark Checker API
The Anthropic Claude Watermark Checker API returns a classifier score as JSON. You cannot read Claude's watermark without Anthropic's secret key.
Store listing polish. Still a classifier for Claude-like writing until a public detector exists.
Launched. Paste text or upload a document to see whether writing looks like Claude.