What happened to Vellum?

discontinued The URL on file (https://www.vellum.ai/sp/showcase) did not respond across three consecutive checks; the streak completed on 2026-09-21.

The address on file matched Vellum's own domain with high confidence, so this observation is reported about Vellum directly. See the methodology for how the match is made.

The vendor's own description, unedited:
Vellum is a development platform specifically designed for building LLM (Large Language Model) applications. It offers a range of tools that facilitate prompt engineering, semantic search, version control, testing, and monitoring. This platform is compatible with all major LLM providers.With Vellum,...

Live alternatives

No active same-category alternatives in the registry yet. The tools index carries everything else that is live.

How this was decided

Not an editorial call. The URL on file failed three consecutive checks, with a confirmation re-probe before the streak counted (a bot-wall response never counts as one), and the 3-miss rule marks the listing discontinued automatically. If the URL responds again, the registry restores it on its own: warn first, then active. Both directions are recorded as events.

Spot an error? Tell us. Corrections to the record append, they never rewrite.