MengRao/fmtlog

Health v2 · maintenance only

Adoption not part of the score

1025 stars · 157 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

fmtlog is a high-performance C++ logging library built on the fmt library, offering nanosecond-level runtime latency and asynchronous multi-threaded logging in time order. It can be used header-only or compiled as a static/shared library, with runtime and compile-time log level filtering.

Use cases

• log with nanosecond-level latency in a low-latency C++ trading system
• replace spdlog with a faster fmtlib-style logger
• do asynchronous multi-threaded logging that preserves time order
• filter and change log levels at runtime
• rate-limit noisy log statements
• handle log messages with a custom callback

When to choose

• you need extremely low logging latency in C++
• you want fmt-style formatting with high throughput
• you want full control over polling and flushing threads

When to avoid

• you need a batteries-included logger with built-in sinks and rotating files like spdlog
• you need platforms beyond Linux and Windows
• you don't want to manage a background polling thread or call poll() yourself

Facets

library · maturity active

logging serialization developer-tools performance backend windows cpp cross-platform fmtlib low-latency asynchronous-logging header-only nanosecond-latency linux

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