OTP

Judgement

What it is

Framework or platform

What it does

Erlang/OTP, the Erlang language, BEAM virtual machine and libraries for building distributed, fault-tolerant systems.

Adopt it when

You build telecom-grade, highly available or massively concurrent systems, or run Elixir.

Watch out

Unusual syntax and a small developer pool.

Ready for

Production-ready

Runs as

Command line and library

Built with

Erlang and C

How established

Established: started 17 years ago, latest release OTP-29.1.2.

What the license allows

You can build it into a product you sell, as long as you keep its copyright notice.

Judged on 2026-11-03 from the project's README and GitHub data. The license and age lines are worked out directly.

Built from

Follow it down: OTP → GCC → LLVM project → runs on a microchip

How compilers were built, back to punched paper tape

Built on OTP: 3 projects

1. 1
   Elixir elixir-lang

   Simple from zero to scale

   Developer tool Production-ready You build real-time or highly concurrent services and want BEAM reliability with friendlier syntax.

   ★ 27k Apache-2.0 Elixir Active, pushed today
2. 2
   Cowboy ninenines

   Small, fast, modern HTTP server for Erlang/OTP.

   Building block Production-ready You build services on the Erlang VM and need the HTTP server layer.

   ★ 7.5k ISC Erlang Active, pushed today
3. 3
   Dgiot dgiot

   Open Source Industrial IoT Platform | 300+ protocols | 6-min deploy | Modbus OPC UA MQTT | 12K Stars

   Framework or platform Usable You are building an industrial IoT deployment with many devices and have staff able to operate Erlang, PostgreSQL and TDengine.

   ★ 4.9k Apache-2.0 Erlang Active, pushed 20 days ago

Open-source alternatives to OTP

1. 1
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   ★ 140k BSD-3-Clause Go Active, pushed today
2. 2
   Rust rust-lang

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   Developer tool Production-ready You need C-level performance with memory safety, for systems software, CLIs, services or WebAssembly.

   ★ 121k Apache-2.0 Rust Active, pushed today
3. 3
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   Developer tool Production-ready You write JavaScript projects of any size and want static types and better editor tooling.

   ★ 112k Apache-2.0 Go Active, pushed today
4. 4
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   ★ 78k See repository Python Active, pushed today
5. 5
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   Developer tool Production-ready You build iOS or macOS apps, or want Swift on Linux servers.

   ★ 71k Apache-2.0 Swift Active, pushed today
6. 6
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7. 7
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8. 8
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