PromptLayer vs Vellum
A side-by-side comparison of PromptLayer and Vellum, two Eval tools, drawn from Ignaite's continuously-verified listings.
Compared from listings verified as of
At a glance
The honest brief
PromptLayer
Treats prompts as a CMS so non-technical experts can edit and version them without code, then eval and monitor in one place.
- Prompt CMS — edit/version without code
- Built-in eval harness + datasets
- Request logging, cost + latency monitoring
- Provider-agnostic across model vendors
- Deploy prompt changes without a release
- Cloud-hosted (no self-host on lower tiers)
- Overlaps with broader observability suites
- Adds another layer to your stack
- Best value at team scale
Vellum
Passes model token costs straight through at cost, so the platform fee is unbundled from usage — unlike marked-up LLMOps tools.
- Visual builder plus Python SDK
- Prompt, RAG, eval, monitoring in one
- Eval and test suites before/after deploy
- Non-technical collaborators supported
- Free tier available
- Cloud-only platform
- Breadth over best-in-class depth
- Seat costs at Pro/Enterprise
- Lock-in to its workflow model