# PixelTach API

> Free, stateless API and MCP server for exact video timing and link checks, from the PixelTach calculator engine (https://pixeltach.com). Nothing sent is stored. Cable length and reach are not modelled.

Use it instead of estimating pixel clocks, blanking and connector capacity. Only width, height and refreshHz are required. Fractional rates are exact: send 59.94, not 60. For broadcast formats (1080p, UHD) send standard "cta". Every response lists the inputs as used and which were defaulted; state those assumptions when you report a result.

## Connect

- MCP server (Streamable HTTP, no key): https://api.pixeltach.com/mcp
- Tools: calculate_timing (timing, pixel clock, bandwidth for one signal), check_link (the same plus fits / tight / exceeds / unsupported for HDMI 1.4 to 2.2, DisplayPort 1.2 to 2.1, SDI, and ST 2110 over 10 to 100 GbE, with headroom and the limiting factor)

## REST

- POST https://api.pixeltach.com/v1/timing (one signal, or {"signals":[...]} up to 50)
- POST https://api.pixeltach.com/v1/link (adds connector verdicts; optional "connectors" filter such as ["hdmi","sdi"])
- GET https://api.pixeltach.com/v1/health
- OpenAPI 3.1: https://api.pixeltach.com/openapi.json
- Documentation: https://api.pixeltach.com/

## Limits

- Rate-limited per IP address (HTTP 429): batch signals instead of sending many requests.
- Body up to 32 KB. Unknown fields are refused with an error that names them.
- HDMI and DisplayPort verdicts are for uncompressed video (no DSC). Verdicts are data-rate only.

## Support

PixelTach is built and paid for by one developer and this API is free. If it saves you time, the annual Supporter subscription at https://pixeltach.com is what keeps it running.