# TinyFn (tinyfn.io)

Hosts 500 deterministic utility functions over MCP and REST so AI agents compute math, conversions and validations exactly rather than estimating them.

- Atlas card: https://inite.ai/en/atlas/tinyfn.io
- Site: https://tinyfn.io
- For: Developers giving AI assistants like Claude or Cursor deterministic math, conversion and validation tools via MCP
- Categories: dev
- Use 0/100 · alive 87/100

## Used for

- count letters in text precisely
- convert units without relying on model guesses
- validate email addresses, URLs and UUIDs

## Price

- from 9 USD/month, free plan (read 2026-10-17 on https://tinyfn.io/#pricing)

## For developers

- OpenAPI: https://tinyfn.io/openapi.json (572 paths)
- API docs: https://tinyfn.io/docs/api-reference
- MCP server: io.tinyfn/tinyfn (namespace; open on 2026-10-17, 572 tools)
- Status page: https://status.tinyfn.io
- Read 2026-10-17

## MCP server, measured daily

Server: https://api.tinyfn.io/mcp/all/, checked every day since 2026-10-19 (4 checks).

- Answered: measuring, 4 daily checks so far
- Median first answer: 177 ms
- Sign-in: none
- Context its tool definitions take: about 29081 tokens (400 tools)
- Tool definitions: B, 83/100
- Failing "description": 14 of 400 tools
- Failing "annotations": 400 of 400 tools
- Warning "open_writes": add, remove_whitespace, add_time, add_time_2, add_business_days
- Warning "destructive_unmarked": truncate, truncate_2, remove_whitespace, remove_duplicate_words, remove_query_param
- Method: https://inite.ai/en/atlas/mcp/report

## Your data

- Certifications stated: gdpr
- Read 2026-10-17

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