Humanloop vs PromptLayer
If you need one place to store prompts, log model calls, and run evals, both tools show up on the shortlist. Humanloop leans toward a full evaluation and feedback platform for teams shipping serious LLM features. PromptLayer started as a logging layer and grew into a prompt registry with a friendly visual editor, so it feels lighter and more like a prompt CMS.
| Dimension | Humanloop | PromptLayer |
|---|---|---|
| What it is | Prompt management, evals, and observability platform | Prompt registry and request logging, plus evals |
| License | Commercial / hosted | Commercial / hosted |
| Origin | Built around evaluation and human feedback | Built around logging LLM requests |
| Who edits prompts | Engineers and PMs, collaborative | Non-engineers too. The visual editor is a strength |
| Evals | A core focus, human and automated | Present, lighter weight |
| Logging / observability | Yes, via SDK | Yes, the original strength |
| Best for | Teams who want evals and feedback loops first | Teams who want prompts out of code, fast |
Pick Humanloop if evaluation and human feedback sit at the center of how you work, and you have PMs and domain experts who review outputs alongside engineers. It fits teams who treat prompt quality as an ongoing measured process.
Pick PromptLayer if you want prompts pulled out of your code into a registry that non-engineers can edit, with request logging you can trust from day one. It gets you a versioned prompt store and a visual editor quickly, which matters when product people own the copy.
These overlap more than either would admit, so decide by where your weight sits. If evals and human review are the point, Humanloop is built for that. If the real need is getting prompts out of code and logging every call so non-engineers can iterate, PromptLayer is the lighter, faster path. One common mistake is buying a hosted platform to solve a problem a free open-source eval runner would handle. Be honest about whether you need the collaboration and logging layer or just a way to test prompts. If it is only the second, look at a free tool before you sign anything.