# Arize Phoenix vs Pydantic Logfire

The deciding difference is operational: Arize Phoenix can run on infrastructure you control, Pydantic Logfire cannot. If that constraint is real for you, it settles the choice before anything else is considered.

| | Arize Phoenix | Pydantic Logfire |
| --- | --- | --- |
| Licence | Open source | Open source |
| Pricing | open source | freemium |
| Self-hostable | Yes | No |
| Languages | Python, TypeScript | Python, TypeScript |
| Install | pip install arize-phoenix | pip install logfire |
| Keys required | None | LOGFIRE_TOKEN |

## Full pages

- https://newagent.build/c/phoenix
- https://newagent.build/c/logfire

## Machine interfaces

- `GET https://newagent.build/api/registry` — every component as JSON
- `GET https://newagent.build/api/vendors` — vendors, with the repo and releases feed to watch
- `GET https://newagent.build/api/advise?q=<plain english>` — recommended stack for a description
- `GET https://newagent.build/api/stack?<layer>=<id>&format=sh|json|md|yml|agents|env` — a stack as files
- `GET https://newagent.build/llms.txt` — the whole registry in one fetch

Any page here also returns markdown if you send `Accept: text/markdown`.