microsoft/mimalloc

Health v2 · maintenance only

Adoption not part of the score

13332 stars · 1165 forks observed · 2026-08-28

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

mimalloc is a compact general-purpose memory allocator developed by Microsoft, serving as a drop-in replacement for malloc with excellent performance characteristics. It uses free list sharding techniques to reduce fragmentation and improve locality, and can be dynamically linked into existing programs without code changes.

Use cases

• replace malloc in C/C++ programs for better performance
• reduce memory fragmentation in long-running services
• speed up allocation-heavy workloads
• override the system allocator via LD_PRELOAD without recompiling
• integrate a small allocator into a language runtime
• achieve bounded worst-case latency for allocation

When to choose

• you need a fast, drop-in malloc replacement with minimal code changes
• your application suffers from allocator contention in multithreaded workloads
• you want a small (~10k LOC), portable allocator that is easy to embed in runtimes
• you need excellent worst-case latencies for large-scale services

When to avoid

• you need garbage collection or language-level memory management rather than a malloc replacement
• your platform is not among the supported ports (Windows, macOS, Linux, BSD, WASM, etc.)
• you require specialized allocators like real-time or GPU allocators
• you want a header-only allocator with zero compiled dependencies

Facets

library · maturity stable

developer-tools developer-tools performance operating-systems windows wasm cpp c cross-platform malloc-replacement memory-allocator drop-in runtime-systems low-latency memory-allocation performance linux macos

Member repositories

For agents

markdown · JSON · MCP: product_card(name="microsoft/mimalloc")