wolfSSL

wolfSSL builds the embedded TLS/SSL library that developers reach for when OpenSSL doesn’t fit — literally. Its core product is a small, C-language TLS/SSL implementation (with the companion wolfCrypt cryptography engine) designed for constrained environments: microcontrollers, RTOS-based devices, IoT hardware, and other footprints where OpenSSL’s memory and binary size are impractical. The library supports current standards including TLS 1.3 and DTLS 1.3, ships an OpenSSL compatibility layer to ease migration, and is reported to be up to 20x smaller than OpenSSL, a meaningful figure for firmware engineers working with kilobytes rather than megabytes of flash and RAM.

Around that core library, wolfSSL has built a family of adjacent products — wolfMQTT, wolfSSH, wolfTPM, wolfBoot (secure bootloader), wolfSentry, wolfHSM, and Java JSSE/JCE providers — that extend the same lightweight-and-portable philosophy into related protocols and use cases like secure boot and hardware security module integration. The company’s software is embedded by silicon and tooling vendors including Renesas and STMicroelectronics as a supported option on their microcontroller platforms, giving it real distribution reach into the embedded and industrial device supply chain beyond direct enterprise sales.

Founded in 2004 and based in Edmonds, Washington, wolfSSL is a small (roughly 11-50 employee), privately held, dual-licensed company — open source under GPLv3 alongside a commercial license for vendors who need to embed it without copyleft obligations. There is no evidence of outside venture funding; the company appears to be sustained by commercial licensing and support revenue from device manufacturers, government, military, and aviation customers rather than by growth-stage capital.