Disclaimer: I am a co-founder of Restate and might be biased.

Restate's spiritual father is Stateful Functions (https://nightlies.apache.org/flink/flink-statefun-docs-maste...) a library for event driven applications built on top of Apache Flink. If you want to learn more about why we started building Restate, I recommend this excellent blog post https://restate.dev/blog/why-we-built-restate.

I understand that Restate and Temporal look similar from a superficial perspective but Restate is not only a durable execution engine but a durable runtime that also provides consistent state and reliable communication. These are the building blocks to build reliable agents and applications w/o having to fit them into a workflow-activity like model. If you want to learn more about how Temporal differs from Restate, check out https://restate.dev/vs/temporal.