Source: https://seerepo.com/compare/huggingface/transformers/vs/vllm-project/vllm
Markdown source: https://seerepo.com/compare/huggingface/transformers/vs/vllm-project/vllm.md
Description: transformers and vllm share 3 technologies: FastAPI, Hugging Face, and psutil. Both are written in Python.

# transformers vs vllm

transformers and vllm share 3 technologies: FastAPI, Hugging Face, and psutil. Both are written in Python.

- [huggingface/transformers](https://seerepo.com/r/huggingface/transformers): 🤗 Transformers: the model-definition framework for state-of-the-art machine learning models in text, vision, audio, and multimodal models, for both inference and training. 
- [vllm-project/vllm](https://seerepo.com/r/vllm-project/vllm): A high-throughput and memory-efficient inference and serving engine for LLMs

## What they share and what sets them apart

- In common: FastAPI, Hugging Face, psutil
- Only in transformers: None
- Only in vllm: axum, gitdb, pyzmq, Tokio, starlette, Ray, AIOHTTP, tower, mkdocs-material, indicatif, NVIDIA, OpenAI, peft, quack-kernels, sentencepiece, torch, transformers, einops, safetensors, triton, torchvision, datasets, torchaudio, MCP, tokenizers, tiktoken, markdown, markupsafe, pymdown-extensions, pillow, image, jinja2, Pydantic, msgspec, jsonschema, pydantic-core, opentelemetry-api, python-json-logger, tracing, prometheus-client, tracing-subscriber, OpenTelemetry, opentelemetry-sdk, prometheus-fastapi-instrumentator

## Side by side

| | transformers | vllm |
|---|---|---|
| Size | 1,811,568 lines written, 3,229 code files | 2,375,117 lines written, 3,289 code files |
| Who writes it | 0.9% of its commits signed by AI. With Claude Code, Cursor, GitHub Copilot, OpenHands, Codex, and Jules | 12.8% of its commits signed by AI. With Claude Code, Codex, Gemini CLI, Cursor, GitHub Copilot, Devin, Mistral Vibe, CodeRabbit, Factory, and Qwen Code |
| Activity | Last push November 4, 2026, 24,118 commits, 168,525 stars | Last push November 4, 2026, 24,593 commits, 96,302 stars |
| Tests | 1,742 test files. 15.6% of its code files have a test that imports them | 2,419 test files. 60.2% of its code files have a test that imports them |

- Size: Lines written by people and agents, without generated ones; code files, without tests.
- Who writes it: A commit counts as AI's when it carries its signature: a Co-Authored-By line, its author name or the merge of its branch.
- Activity: From GitHub and its history, on the day SeeRepo read it.
- Tests: The files that test the code, and the share of code files a test imports.

## Frequently asked questions

### Which is bigger, transformers or vllm?

vllm, with 2,375,117 lines written; transformers has 1,811,568.

The proof: [vllm-project/vllm's code at commit 75f6761](https://github.com/vllm-project/vllm/tree/75f67614971a44050140e3422c1a65fe5004a72b)

### Which has more GitHub stars, transformers or vllm?

transformers, with 168,525 stars; vllm has 96,302.

The proof: [huggingface/transformers on GitHub](https://github.com/huggingface/transformers)

### Which has more tests, transformers or vllm?

vllm, with 2,419 test files; transformers has 1,742.

The proof: [vllm-project/vllm's code at commit 75f6761](https://github.com/vllm-project/vllm/tree/75f67614971a44050140e3422c1a65fe5004a72b)

### Which was updated more recently, transformers or vllm?

Both got their last push on November 4, 2026.

The proof: [vllm-project/vllm's commits on GitHub](https://github.com/vllm-project/vllm/commits)

### Which has more commits signed by AI, transformers or vllm?

vllm: an AI signed 12.8% of its commits, with Claude Code, Codex, Gemini CLI, Cursor, GitHub Copilot, Devin, Mistral Vibe, CodeRabbit, Factory, and Qwen Code; in transformers, 0.9%.

The proof: [the commits each tool signed in vllm-project/vllm](https://seerepo.com/r/vllm-project/vllm/ai)

## Sources

- huggingface/transformers: Read on November 4, 2026, at commit fd3cf01 (https://github.com/huggingface/transformers/tree/fd3cf0140de03f7619ac95b5cfed05b711ff9e22)
- vllm-project/vllm: Read on November 4, 2026, at commit 75f6761 (https://github.com/vllm-project/vllm/tree/75f67614971a44050140e3422c1a65fe5004a72b)

## What is your repo built with?

Any public repo, with no account: https://seerepo.com/r/owner/repo/built, with the owner and name it has on GitHub.