WolfMQTT does not have a direct configuration to eliminate heap usage, but you can manually redefine allocation macros and use static buffers.
WOLFSSL_NO_MALLOC does aim to disable heap usage in WolfSSL, but some manual inspection and adjustment of the code might still be needed.
Please post questions or comments you have about wolfSSL products here. It is helpful to be as descriptive as possible when asking your questions.
ReferencesStable Releases - download stable product releases.
Development Branch - latest development branch on GitHub.
wolfSSL Manual - wolfSSL (formerly CyaSSL) product manual and API reference.