Implementation model
Written in Rust, end to end.
Rust Pure is one of three standalone runtime-native engines in the family, alongside Java Pure and .NET Pure. It does not call into the C++ FIX engine: the generated coverage matrix records each of these categories as implemented by Rust Pure itself.
Lifecycle and recovery
Initiator and acceptor Logon, heartbeat, TestRequest and Logout; gap detection, ResendRequest, replay, GapFill, PossDup and sequence reset.
TCP and TLS
Initiator and acceptor operation, TLS and mutual TLS, certificate and hostname checks, reconnect and backup endpoints.
Durable stores and audit
Message stores, persisted sequences, resend windows, fail-closed writes and exact-wire audit logging.
Runtime dictionaries
Required fields, data types, enums, field order, duplicate tags, repeating groups and reject codes.
Generated binding coverage matrix reviewed on 30 September 2026: 79 of 79 tracked API capabilities (11 recorded n/a) and all 27 tracked session behaviors. Capability map for all six flavors →
Protocol scope
FIX sessions, recovery and durable state.
- FIX versions: the bundled QuickFIX-format dictionaries for FIX 4.0 to FIX 5.0 SP2 and FIXT 1.1 load at runtime on every LibHFT surface, Rust Pure included. FIX versions supported →
- Recovery: sequence gaps, ResendRequest, PossDup replay and GapFill are owned by Rust Pure. FIX session recovery →
- High availability: writer-lock arbitration, standby retry, promotion and sequence restore are recorded for Rust Pure. High availability →
- Protocol selection: use the protocol coverage guide for the supported implementation of FIX, FAST, SBE and venue-specific message tracks.
Measured results · HP, 19–20 September 2026
Rust Pure at 50,000 messages per second.
The HP open-loop reference campaign, collected on 19 September 2026 and recorded on 20 September 2026 on the HP reference host (Intel Xeon Gold 6254), ran one Rust Pure session against a sustained 50,000 NewOrderSingle → ExecutionReport requests per second. Response time runs from the intended send slot, so scheduler delay is included; each percentile is the mean of three 30-second runs.
| Transport | p50 | p99 | p99.9 | Maximum |
|---|---|---|---|---|
| Kernel TCP | 14.504 µs | 15.876 µs | 18.233 µs | 64.199 µs |
| Solarflare Onload | 6.491 µs | 6.870 µs | 6.961 µs | 19.418 µs |
| Mellanox VMA | 6.979 µs | 7.166 µs | 7.265 µs | 17.736 µs |
| Solarflare TCPDirect | 5.869 µs | 6.029 µs | 6.088 µs | 12.072 µs |
| Mellanox SocketXtreme | 6.905 µs | 7.575 µs | 8.731 µs | 19.533 µs |
Evidence: Rust FIX engine benchmarks · how the campaign was measured · results table (TSV). Rust Pure was not part of the 29 September 2026 SCAN capacity sweep; a matched sweep is pending, so no sustained-rate ceiling is published for it. Capacity brackets →
Codec work is measured separately in the qualified 25-adapter HP campaign of 18 October 2026, beside the other Rust codecs. Rust codec microbenchmarks → · Rust engine comparison →
Earlier canonical Rust comparison profiles (Rust open / NanoFIX and TrueFix) were superseded after a clock-boundary review. Their original status cells remain historical and cannot establish a current comparison. Current publication gates →
Transport track
Hardware-aware FIX transport.
The HP campaign above measured Rust Pure over kernel TCP, Onload, VMA, TCPDirect and SocketXtreme. Select the transport for your NIC, driver and runtime, then verify the initiator and acceptor roles you need. The Rust campaign records the measured paths; the family coverage matrix describes its separately classified vendor integrations.
QuickFIX
Bring your FIX dictionaries.
Reuse your QuickFIX-format XML dictionaries when moving a FIX application to Rust. Assess the existing session settings, adapt the application to the Rust API, then verify replay and recovery before benchmarking or cutover.
Selection
When Rust Pure fits.
- Choose Rust Pure when a standalone Rust engine is the architectural requirement.
- Confirm vendor SDK and initiator/acceptor support for the exact transport configuration you plan to deploy.
- Benchmark the exact flavor, transport, message path and deployment hardware you will operate.