head to head · open source

llama.cpp vs Arize Phoenix

llama.cpp has 128,581 GitHub stars, 23,334 forks, 2,464 open issues and last shipped yesterday. Arize Phoenix has 11,518 stars, 1,135 forks, 970 open issues and last shipped yesterday. llama.cpp leads on adoption by 1,016% (128,581 vs 11,518 stars). llama.cpp is written in C++ under MIT; Arize Phoenix is written in Python under a custom or non-standard licence. llama.cpp has attracted 18% as many forks as stars, Arize Phoenix 10%. Arize Phoenix was the more recently maintained of the two, and both are self-hostable with no licence fee.

Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.

llama.cpp ★ 129K Arize Phoenix ★ 12K category AI & Machine Learning

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Side by side

	llama.cpp	Arize Phoenix
GitHub stars	★ 129K	★ 12K
License	MIT	Custom / other
Written in	C++	Python
Last push	2026-09-17	2026-09-17
Forks	⑂ 23K	⑂ 1.1K
Self-hosting	Yes	Yes
Data ownership	Your server	Your server

pick llama.cpp if

You weight community size — 129K stars and counting
You want the MIT license terms
Your stack matches C++
You value the larger contributor base for long-term maintenance

full llama.cpp profile →

pick Arize Phoenix if

You want the Arize Phoenix feature set and don't need the biggest community
You prefer the Custom / other license terms
Your stack matches Python
You evaluated both and Arize Phoenix fits your workflow better

full Arize Phoenix profile →

About llama.cpp

llama.cpp is a C/C++ library and set of command line tools for running large language models (LLMs) and vision language models (VLMs) locally. It enables inference without external dependencies, targeting diverse hardware including Apple Silicon, x86 CPUs, NVIDIA GPUs (via CUDA), AMD GPUs (via HIP), and other accelerators. The project lives in the ggml ecosystem, leveraging the ggml tensor computation library for low level operations and quantized model execution.

read the full llama.cpp overview →

About Arize Phoenix

Arize Phoenix is an open source AI observability platform for experimentation, evaluation, and troubleshooting. It lives in the machine learning infrastructure ecosystem and is written in Python. The project provides tracing, evaluation, datasets, experiments, prompt management, and a playground for LLM applications.

read the full Arize Phoenix overview →

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Frequently asked questions

Is llama.cpp or Arize Phoenix more popular?

llama.cpp has 128,581 GitHub stars and Arize Phoenix has 11,518. llama.cpp has the larger community by that measure.

Are llama.cpp and Arize Phoenix free?

Both are open source. llama.cpp is licensed under MIT, and Arize Phoenix has no licence declared in this registry. Both are free to self-host.

What is the difference between llama.cpp and Arize Phoenix?

llama.cpp is written in C++ and Arize Phoenix in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.

Which should I choose, llama.cpp or Arize Phoenix?

Choose llama.cpp if you want the larger community (128,581 stars) or its MIT licence terms. Choose Arize Phoenix if its feature set, stack or Custom / other licence fits better. Both are self-hostable.