# ETLCPP/etl

Embedded Template Library

Repository: https://github.com/ETLCPP/etl
Canonical: https://ross.abutalabs.com/products/etl
Homepage: https://www.etlcpp.com
Language: C++
License: MIT
License Family: permissive
Topics: c-plus-plus, embedded-applications, cpp, templates, library, algorithms, containers, estd, std, stl, embedded, embedded-systems
Last push: 2026-08-26T19:16:54+00:00

## Health v2 (maintenance only)
Score: 97/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 92, longevity 100
- inputs: {"age_days": 4339, "days_push": 7, "days_rel": 53, "gap_med": 4.0, "n_releases_24m": 27}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3107, forks 540 (observed 2026-08-28T04:07:43.801313+00:00)

## What it is
The Embedded Template Library (ETL) is a C++ library providing STL-like containers, algorithms, and utilities designed for embedded systems with deterministic memory usage and no dynamic allocation. It supports C++98 through C++26 and works even on compilers without full STL support.

## Use cases
- use STL-style containers in embedded C++ firmware without heap allocation
- replace std::vector and std::map with fixed-capacity equivalents for deterministic memory
- write portable C++ that compiles on compilers lacking full STL support
- build lock-free queues and pools for interrupt-driven embedded code
- use chrono, variant, and span features on older C++ toolchains
- develop Arduino or RTOS applications with type-safe containers

## When to choose
- you develop embedded or real-time C++ software where dynamic allocation is forbidden or undesirable
- you need STL-like APIs with fixed-size, deterministic containers
- you target compilers with incomplete or no C++ standard library support

## When to avoid
- you write general-purpose desktop or server C++ where the standard library is fully available
- you need dynamically growing containers with unlimited capacity
- your project is C, not C++

## Facets
- artifact type: library
- maturity: active
- function: concurrency, developer-tools, math, date-time, serialization
- domain: embedded-systems, developer-tools
- platform: cpp, embedded, cross-platform
- tags: stl-alternative, containers, no-heap, deterministic, templates, c-plus-plus, fixed-capacity, rtos, algorithms

## Member repositories
- ETLCPP/etl (main) score 97

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:43.801313+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:26:58.224668+00:00, confidence not recorded.
  - readme: https://github.com/ETLCPP/etl (fetched 2026-08-28T04:07:43.801313+00:00, sha 2ad34bb33fad)
  - homepage: https://www.etlcpp.com (fetched 2026-08-29T09:42:00.024014+00:00, sha 2e20d71befa4)
  - site_page: https://www.etlcpp.com/docs (fetched 2026-08-29T09:42:00.033158+00:00, sha a5e90d28a82f)
- Data as of 2026-08-30T08:39:29.467469+00:00.