EvidentSource Documentation

Design, try, and deploy. Three surfaces, one platform — Designer to model it, Sandbox to try it, EvidentSource to run it in your cloud.

Start somewhere

Try the Sandbox A free, hosted EvidentSource. Issue a command, read a state view, watch an event trace.

Design your first system Use Designer to model events, commands, and views, then generate code.

Designer → Sandbox End-to-end walkthrough. Model it, generate it, deploy it, exercise it.

Events are the record

Every business action is captured as an immutable event with full context. State is derived from events, not the other way around.

Two pure functions

decide turns commands into events. evolve folds events into queryable state. That's the programming model.

Bi-temporal by default

Every event carries transaction time and effective time. "What did we know, and when did we know it?" is a query, not an investigation.

gRPC API The primary programmatic interface. Every SDK is built on top of it.

REST API JSON projection of the gRPC surface — for curl, browsers, and languages without SDKs.

MCP API Model Context Protocol endpoint for AI agents.

SDKs Overview of Rust, Go, TypeScript, Python, and .NET SDKs.

Operations: containers + S3 One container for the runtime, S3 for storage. That's the whole operational story.

AWS Marketplace deployment CloudFormation stack for a production EvidentSource in your own AWS account.