AWS Step Functions vs Restate

AWS Step Functions is a cloud workflow service for coordinating AWS services and HTTPS endpoints, including SaaS applications. Workflows are state machines written in Amazon States Language, with Workflow Studio providing a visual designer. Definitions can branch, run steps in parallel, set timeouts, retry failures, and handle errors with try/catch or rollback patterns. Service integrations connect to over 200 AWS services, while AWS SDK integrations can invoke over 9,000 API actions. HTTPS endpoint integration connects directly to HTTP-based services. Distributed Map can process large datasets, including Amazon S3 data, with up to 10,000 parallel child executions in one Map Run. Execution history, CloudWatch Logs, and AWS X-Ray support review and tracing. Standard executions can run for up to one year; Express executions can run for up to five minutes. Task, state, or execution input and output is limited to 256 KiB. A Free Tier plan is listed at free indefinitely; Standard and Express plans bill usage.

Restate is a durable execution runtime for building resilient services, workflows, and AI agents. It records progress during execution and resumes after failures without discarding completed work. Its building blocks include durable functions, workflows, Virtual Objects, queues, durable RPC, timers, signals, and flow control. The interface exposes execution journals and controls to cancel, kill, restart, or pause executions. Restate runs as a self-hosted single binary, managed Restate Cloud, or BYOC in a customer cloud account. Listed SDKs include TypeScript, Python, Java, Go, Kotlin, Rust, and Ruby. Integrations include Vercel AI SDK, OpenAI Agents SDK, Google ADK, Google Gemini, Pydantic AI, and LangChain. The homepage reports under 10ms P99 latency overhead under load for durable actions. The Free plan is free for 50k durable actions monthly with no credit card. Restate Cloud starts at $75 a month.