# TraceTail (tracetail.io)

Computes a stable browser visitor ID from 40 browser signals, recognizing returning visitors without cookies or local storage.

- Atlas card: https://inite.ai/en/atlas/tracetail.io
- Site: https://tracetail.io
- For: Web developers and teams who need to recognize returning browsers and fight signup abuse, account takeover or bots without cookies.
- Use 0/100 · alive 100/100

## Used for

- flag sign-ins from devices an account has never used
- detect one device opening many accounts to claim promo offers
- rate-limit scrapers and bots by visitor ID instead of IP

## Price

- from 0.1 USD/usage, free plan (read 2026-10-20 on https://tracetail.io/pricing)

## For developers

- OpenAPI: https://tracetail.io/openapi.json (8 paths)
- MCP server: io.tracetail/tracetail (namespace; open on 2026-10-20, 6 tools)
- Status page: https://tracetail.io/status
- Read 2026-10-20

## MCP server, measured daily

Server: https://tracetail.io/mcp, checked every day since 2026-10-20 (16 checks).

- Answered: 100% of daily checks
- Median first answer: 313 ms
- Sign-in: none
- Context its tool definitions take: about 1153 tokens (6 tools)
- Tool definitions: A, 100/100
- Warning "open_writes": create_setup_link
- Method: https://inite.ai/en/atlas/mcp/report

## Your data

- Certifications stated: gdpr
- Read 2026-10-20

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Source: INITE Atlas, https://inite.ai/en/atlas/tracetail.io. JSON: https://inite.ai/api/atlas/tracetail.io. MCP: https://inite.ai/api/mcp (atlas_lookup).