Restate

The customer's tool calls are made durable rather than supplied: Restate's tools pattern journals each tool execution so it is not repeated on retry, and its SDK integrations (OpenAI Agents SDK, Pydantic AI, Vercel AI SDK, Google ADK, LangChain, LiteLLM) run agents built on those frameworks with their tools. No connector catalog or authenticated action framework of Restate's own is documented, so the tools are the customer's code or the framework's.

Sourcedocs.restate.dev/ai/patterns/toolsread 2026-09-25

As a workflow and service runtime, Restate lets handlers call other services durably, run steps concurrently, sleep on durable timers, wait on external events and run sagas with compensation, and its AI patterns document sequential, parallel, orchestrator and evaluator workflows, multi-agent routing and remote agents.

Sourcedocs.restate.dev/ai/patterns/multi-agentread 2026-09-25

No retrieval structure Restate maintains over the customer's corpus is documented. Restate runs the agent's code durably; any indexing, embeddings store or retrieval belongs to the customer's code or the agent framework it runs.

Sourcedocs.restate.dev/ai/indexread 2026-09-25

Durable waits let the customer's code hold for a person: Restate's human-in-the-loop pattern has the agent pause on a durable approval promise (an awakeable) that a person's response resolves, and resume where it left off even across restarts. This is a general wait applied to approval, and no approval step, approver identity or review surface of Restate's own is documented. Cancel, kill and restart in the UI are operator controls over invocations, not a review of the agent's action, and rollback is a compensation pattern the customer writes.

Sourcedocs.restate.dev/ai/patterns/human-in-the-loopread 2026-09-25

Restate documents compliance but not a named access model. The pricing page shows a SOC 2 Certified badge. Restate Cloud is said to provide built-in authentication and access control without naming roles, SSO or permissions; self-hosted deployments put the ingress behind the customer's own reverse proxy and restrict the admin port with network controls, a gate the customer owns; request signing with ED25519 keys secures Restate's calls to services; and BYOC's scoped Kubernetes RBAC token governs Restate's own management access, not the buyer's users.

Sourcedocs.restate.dev/server/securityread 2026-09-25

What the agent did is recorded step by step by Restate itself: the execution journal records every model call, tool execution, routing decision and state change, the Restate UI gives a live view of invocations and their journals, traces export over OpenTelemetry, and the SQL introspection API queries invocations and state. Logfire, Langfuse and Arize Phoenix are optional integrations, not the source.

Sourcedocs.restate.dev/ai/patterns/observability-controlread 2026-09-25

Virtual Objects are documented as persistent, isolated agent sessions: each is keyed by an ID such as a user or conversation, keeps its own state across invocations, and serializes concurrent requests. The agent's handlers write the state; it is scoped per object key, so one user's or conversation's state can be removed without touching the rest; the docs state its lifetime, retained indefinitely until explicitly cleared, with clear and clear-all calls as the purge path (workflow state follows the workflow's retention time instead); and the state can be inspected and edited in the Restate UI and CLI, and queried through the SQL introspection API.

Sourcedocs.restate.dev/ai/patterns/sessionsread 2026-09-25

Deployment into the customer's own environment comes three ways: the server self-hosts as a single binary with guides for Docker, Kubernetes, AWS, Google Cloud and Azure; BYOC runs a managed Restate in the customer's own cloud account, VPC and chosen region; and Restate Cloud is the fully managed option. The server is source available under the Business Source License 1.1, converting to Apache 2.0 four years after each release, with a grant that bars offering it as a public Restate platform service (per the repository's license file).

Sourcedocs.restate.dev/byoc/overviewread 2026-09-25

The ready-made starting points Restate ships are AI examples, a library of agent patterns (sessions, human-in-the-loop, multi-agent, rollback, parallelization, evaluator workflows) and integration guides for six agent SDKs. These are examples a developer builds from, not a catalog of agents a buyer adopts.

Sourcedocs.restate.dev/ai/ai-examplesread 2026-09-25

Events and schedules start work on their own: Restate manages Kafka consumers itself and pushes each event on a subscribed topic to a handler as an invocation, handlers can schedule delayed calls to run later, and its cron guide builds recurring jobs on those delayed calls.

Sourcedocs.restate.dev/services/invocation/kafkaread 2026-09-25

Restate runs no models and offers no model surface of its own: the model is chosen in the agent framework or client library the customer's code uses (LiteLLM, the OpenAI Agents SDK, the Vercel AI SDK and others), and Restate makes those calls durable.

Sourcedocs.restate.dev/ai/sdk-integrations/litellmread 2026-09-25

Restate is callable from outside: every handler is invokable over HTTP through the ingress, typed clients ship in the TypeScript, Java, Python and Go SDKs (with SDKs in Kotlin and Rust as well), a documented admin REST API with an OpenAPI schema manages deployments, invocations and state, and a CLI covers the same operations.

Sourcedocs.restate.dev/services/invocation/httpread 2026-09-25

Restate ships testing tools for handler logic: a Testcontainers companion library in its SDKs runs a Restate server so tests exercise services, state and durable steps before deployment. Those tests show whether the code behaves, not how well an agent's output performs, and agent evaluation itself runs in third-party integrations (Logfire, Langfuse, Arize Phoenix), not in Restate.

Sourcedocs.restate.dev/develop/ts/testingread 2026-09-25

No browser or desktop the agent operates, and no browser environment of Restate's own, is documented. Restate runs the customer's handlers wherever they are deployed and makes their steps durable.

Sourcedocs.restate.dev/ai/indexread 2026-09-25