PQM4: Post-quantum crypto library for the ARM Cortex-M4. The pqm4 library, benchmarking and testing framework started as a result of the PQCRYPTO project funded by the European Commission in the H2020 program. It currently contains implementations post-quantum key-encapsulation mechanisms and post-quantum signature schemes targeting the ARM Cortex-M4 family of microcontrollers. The design goals of the library are to offer: automated functional testing on a widely available development board; automated generation of test vectors and comparison against output of a reference implementation running host-side (i.e., on the computer the development board is connected to); automated benchmarking for speed, stack usage, and code-size; automated profiling of cycles spent in symmetric primitives (SHA-2, SHA-3, AES); integration of clean implementations from PQClean; and easy integration of new schemes and implementations into the framework.