The deciding difference is operational: vLLM can run on infrastructure you control, Anthropic cannot. If that constraint is real for you, it settles the choice before anything else is considered.
Claude Opus, Sonnet and Haiku. Strong tool use and long-horizon agentic work.
Enable prompt caching on the system prompt and tool definitions — it is the single biggest cost lever.
High-throughput open-weight serving on your own GPUs.
| Anthropic | vLLM | |
|---|---|---|
| Licence | Proprietary | Open source |
| Pricing | usage based | open source |
| Self-hostable | No | Yes |
| Languages | TypeScript, Python | Python |
| Install | npm install @anthropic-ai/sdk | pip install vllm |
| Keys required | ANTHROPIC_API_KEY | None |
The deciding difference is operational: vLLM can run on infrastructure you control, Anthropic cannot. If that constraint is real for you, it settles the choice before anything else is considered. Anthropic: Claude Opus, Sonnet and Haiku. Strong tool use and long-horizon agentic work. vLLM: High-throughput open-weight serving on your own GPUs.
Anthropic is a hosted service only. vLLM can run on your own infrastructure.
Anthropic is proprietary (usage based). vLLM is open source (open source).
Every page here answers to Accept: text/markdown and returns the same content at roughly a tenth the tokens. No separate site, no toggle — same URL.
curl -s -H "Accept: text/markdown" https://newagent.build/compare/anthropic-vs-vllm