Download a template

Each template is a complete, working HEART for one language or platform. Pick the one closest to your system, then follow its comments. Each carries an ID (heart/embeddedstandard/<name>/v1.2611.1) so tools can tell which one you started from.

HEART 1 templates, v1.2611.1

Latestpublished 2026-11-12

Every template in one zip, with the catalog, licence and notices.

All 17 templates 257 KB

catalog-v1.2611.1.jsonevery template, its class and test status

Language and platform	Class and connection	Tested
Arduino C++ Uno, Nano, Mega, ESP32, ESP8266, RP2040	Core-S serial-line	untested	Download 15 KB
ARM Thumb-2 assembly (GNU as) Cortex-M3, M4, M7, M33 (STM32, nRF52, SAM, LPC, RP2350)	Core-S serial-line	untested	Download 17 KB
RISC-V assembly (RV32IM, GNU as) ESP32-C3/C6, GD32V, SiFive, CH32V, any RV32IM core	Core-S serial-line	untested	Download 17 KB
x86-64 assembly (GNU as, Intel syntax) x86-64 Linux, industrial PCs, as a model for other assembly ports	Core-S serial-line	tested	Download 17 KB
Python 3.8+ Any Linux, Raspberry Pi, building controller	Gateway helper serial-line to http-server	tested	Download 22 KB
C99, no heap, no stdio Any microcontroller: ARM Cortex-M, RISC-V, AVR, ESP32, PIC, MSP430	Core-S serial-line	tested	Download 19 KB
C99 (POSIX) Embedded Linux, BSD, macOS, Yocto, Buildroot, OpenWrt	Core-M http-server	tested	Download 22 KB
C99 core + ESP-IDF 5.2 port ESP32, ESP32-S3, ESP32-C3, ESP32-C6 (Wi-Fi); the core on any C99 target	Core-M http-server	tested	Download 115 KB
Go 1.20+ Linux, macOS, Windows, embedded Linux (ARM, RISC-V, MIPS)	Core-M http-server	tested	Download 19 KB
Java 11+ (JDK only) Linux, Windows, industrial PCs, gateways	Core-M http-server	tested	Download 20 KB
JavaScript (Node.js 18+) Linux, macOS, Windows, Electron	Core-M http-server	tested	Download 18 KB
MicroPython 1.20+ (also runs on CPython) ESP32, Raspberry Pi Pico, STM32, nRF	Core-S serial-line	tested	Download 15 KB
PHP 8.0+ Web servers, shared hosting, CMS plug-ins	Core-M http-server	tested	Download 19 KB
Python 3.8+ Linux, macOS, Windows, Raspberry Pi	Core-M http-server	tested	Download 28 KB
Ruby 3.0+ (stdlib only) Linux, macOS, web back ends	Core-M http-server	tested	Download 18 KB
Rust 1.70+ (std only) Embedded Linux, desktop, server	Core-M http-server	tested	Download 21 KB
WebAssembly text format (hand-written) Browsers, Node, plug-in hosts, WAMR and wasm3 on microcontrollers	Core-S serial-line	tested	Download 18 KB

Core-S fits small microcontrollers; Core-M needs an operating system. "Untested" means the tools to build it were not available when this release was made: see each template's notes. All templates are Apache-2.0.

HEART Core: the reference runtime, in Rust

0.3.0 published 2026-11-12

The Core library, the heartd daemon, WebAssembly for apps, examples and the conformance suite. Dual-licensed Apache-2.0 or MIT.
Read me

HEART Core 0.3.0 855 KB

Older versions

Every version ever published stays here, unchanged.

Templates v1.2611 (HEART 1, published 2026-11-11)

All 17 templates (247 KB) · catalog

Arduino C++ (15 KB)
ARM Thumb-2 assembly (GNU as) (17 KB)
RISC-V assembly (RV32IM, GNU as) (17 KB)
x86-64 assembly (GNU as, Intel syntax) (17 KB)
Python 3.8+ (22 KB)
C99, no heap, no stdio (19 KB)
C99 (POSIX) (22 KB)
C99 core + ESP-IDF 5.2 port (110 KB)
Go 1.20+ (19 KB)
Java 11+ (JDK only) (20 KB)
JavaScript (Node.js 18+) (18 KB)
MicroPython 1.20+ (also runs on CPython) (15 KB)
PHP 8.0+ (19 KB)
Python 3.8+ (25 KB)
Ruby 3.0+ (stdlib only) (18 KB)
Rust 1.70+ (std only) (21 KB)
WebAssembly text format (hand-written) (18 KB)

HEART Core, earlier versions

HEART Core 0.2.0 (850 KB), published 2026-11-12
HEART Core 0.1.0 (737 KB), published 2026-11-11