FIDE Pairing Engine

Not yet FIDE-approved — for testing only. ChessRoster’s FIDE pairing engine has not been approved by FIDE. It is provided for testing and evaluation while approval is pending, and should not be relied on to pair or rate an official FIDE-rated event. We will update this page once approval is granted.

Engine attribution

ChessRoster’s FIDE pairing and tie-break calculations are built on a modified version of Gacrux, Otto Milvang’s FIDE TieBreakServer reference implementation. Gacrux is MIT licensed, © FIDE, and was donated to FIDE by Otto Milvang.

We apply robustness fixes and a small set of integration adaptations. The underlying pairing and tie-break algorithms remain Gacrux’s reference implementation.

Public test utilities

ChessRoster provides two free public tools for testing FIDE tournament data:

RTG (Random Tournament Generator) creates reproducible individual or team FIDE tournaments in TRF format. Supply a seed to reproduce an event exactly; when omitted, the response returns the server-selected seed.
PTC (Pairing and Tie-break Checker) accepts TRF data and returns validation findings, round details, and, when configured in the TRF, computed standings.

Use the FIDE RTG and PTC Swagger page to run either tool interactively and copy ready-made request examples.

RTG to PTC workflow

In Swagger, run POST /pair/fide/generate with an individual configuration or a nested team configuration.
Copy the returned trf_content and resolved seed.
Paste that TRF into POST /pair/fide/check.
Use strict: true for additional FIDE rule findings. Use deep: true to compare every completed round with the deterministic pairing prescribed by the engine; differences are reported board by board and include colour.

The public tools are intended for testing and validation. Tournament directors running events in ChessRoster use the tournament pairing workflow, which preserves registrations, results, and published pairings in the event record.