Restate
The durable runtime for agents and backends.
Restate is a lightweight durable-execution runtime purpose-built for AI agents and workflows — journaling every step so invocations survive crashes, retries are deterministic, and long-running agent tasks run reliably. Raised a $20M Series A in September 2026 to 'define the infrastructure layer for AI agents'.
In the news
Restate raises $20M Series A for agent infrastructure
Restate raises $20M to 'define the infrastructure layer for AI agents and workflows' — its lightweight durable runtime journals every agent step so invocations survive crashes. The round underlines durable execution as the best-funded sub-category of agent infrastructure.
Temporal raises $300M Series D at $5B valuation
Durable-execution leader Temporal closes a $300M Series D led by a16z at a $5B valuation, reporting 380% YoY revenue growth and 20M+ monthly installs. The agent-infra thesis in one round: in-memory agent state breaks in production, and durable execution is the production architecture.
Related startups
LangChain
The de-facto standard toolkit for building LLM applications and agents.
LangChain makes the LangChain framework and LangGraph, the low-level orchestration standard for stateful, controllable agents, plus the LangSmith platform for tracing, evaluating and monitoring them in production.
Sierra
Conversational AI agents for customer experience.
Sierra, co-founded by Bret Taylor and Clay Bavor, builds production conversational agents that resolve real customer issues with guardrails, evaluation and human escalation — a template for deploying vertical agents at the enterprise edge.
CrewAI
Multi-agent orchestration, from open-source framework to enterprise platform.
CrewAI popularized role-based multi-agent teams ('crews') with a simple mental model and ships an enterprise control plane for deploying, monitoring and governing them.