fmtlib/fmt

Health v2 · maintenance only

Adoption not part of the score

23765 stars · 2959 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

{fmt} is a fast, safe C++ formatting library providing an alternative to C stdio and C++ iostreams, implementing C++20 std::format and C++23 std::print. It offers Python-like format string syntax, portable Unicode support, and high-performance floating-point and integer conversion.

Use cases

• format strings in c++ faster than printf
• replace iostreams with a modern formatting api
• implement std::format on older c++ compilers
• format floating point numbers with correct rounding
• safe printf with positional arguments
• format dates and times with chrono
• format user-defined types in c++

When to choose

• you need fast, type-safe text formatting in C++
• you want std::format/std::print on compilers lacking them
• you need portable Unicode-aware formatting across platforms

When to avoid

• your project is C-only (use a C formatting library instead)
• you need locale-specific number formatting beyond positional arguments
• you are locked into iostream-based logging frameworks already

Facets

library · maturity stable

serialization developer-tools developer-tools cross-platform performance cpp cross-platform windows formatting printf iostreams unicode chrono std-format floating-point linux macos

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