spdlite

A small, header-only C++20 logger - the lite version of spdlog, simpler, smaller, fewer features.

Use spdlite if you want a tiny, fast, capable logger.

Install

Just copy the include/spdlite/ folder into your build tree.

Quick start

#include "spdlite/logger.h"
#include "spdlite/sinks/console_sink.h"

int main() {
    using namespace spdlite;
    logger_st<console_sink> log("app", console_sink{});

    log.info("Hello {}", "world");
    log.info("Value: {}", 42);
    log.warn("Something happened");
    log.error("Failed with code {}", -1);
}

Output:

[2026-04-11 10:30:45.123] [app] [INF] Hello world
[2026-04-11 10:30:45.123] [app] [INF] Value: 42
[2026-04-11 10:30:45.123] [app] [WRN] Something happened
[2026-04-11 10:30:45.123] [app] [ERR] Failed with code -1

See include/spdlite/logger.h for the full API and include/spdlite/sinks/ for the available sinks.

fmt vs std::format

If you'd rather use <format> (zero vendored dependencies, smaller install), define SPDLITE_USE_STD_FORMAT and the fmt/ subfolder can be left out:

$ cmake -DCMAKE_CXX_FLAGS="-DSPDLITE_USE_STD_FORMAT" ..

Formatter options

The default header is [YYYY-MM-DD HH:MM:SS.mmm] [name] [LVL] payload. Reconfigure via format_options:

log.format_options({.utc = true});
log.format_options({.precision = time_precision::ns});
log.format_options({.show_date = false, .precision = time_precision::none});

See the table below for all available fields:

Field	Default	Effect
utc	false	Use gmtime instead of localtime.
show_date	true	Include the YYYY-MM-DD prefix.
show_thread_id	false	Include a 6-digit thread id after the timestamp.
precision	time_precision::ms	Fractional digits: none, ms (3), us (6), or ns (9).

Benchmarks

Build and run:

$ cmake -B build -DSPDLITE_BUILD_BENCH=ON .
$ cmake --build build
$ ./build/latency           # quick set
$ ./build/latency full      # adds multi-threaded + file I/O

License

MIT