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![rryssf_ Avatar](https://lunarcrush.com/gi/w:24/cr:twitter::1666103476945031168.png) Robert Youssef [@rryssf_](/creator/twitter/rryssf_) on x 2688 followers
Created: 2025-07-20 17:01:16 UTC

X. Vellum

this is what you use when your AI agents actually have to work… in prod.

built-in evals, test-case banks, version control. you can switch between visual and code instantly.

feels like the Datadog of prompt engineering. free trial, but pricing is custom.

![](https://pbs.twimg.com/media/GwUO1WRbEAAPaK2.png)

XXXXX engagements

![Engagements Line Chart](https://lunarcrush.com/gi/w:600/p:tweet::1946978726019060068/c:line.svg)

**Related Topics**
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[Post Link](https://x.com/rryssf_/status/1946978726019060068)