Where every business action is captured with full context, making AI agents auditable and AI-generated code reliable.
Pure functions. Bi-temporal indexing. Complete audit trails.
Your cloud, your data, open standards.
A bi-temporal event sourcing platform where every business action is captured as an immutable event, indexed for query across multiple dimensions, and materialized into consistent state views via pure-function WebAssembly components.
Decision traces, not snapshots
AI agents need the full business narrative, not just current state. EvidentSource captures every action with complete context — what happened, when, why, under what policy. Full context before acting, complete auditability after.
The pit of success architecture
Your entire programming model is two pure functions: decide() and evolve(). No distributed transactions, no eventual consistency puzzles. Junior developers, offshore teams, and AI coding agents all produce correct code — the architecture makes it hard to do the wrong thing.
Open standards, no lock-in
Deploy to your AWS account via AWS Marketplace. Your data never leaves your infrastructure — we're out of scope for your audits. Built on CloudEvents (CNCF) and WASM Component Model standards. Your data, your Kafka, your DynamoDB.
Two pure functions. That's it.
// decide(): Handle command, query state, return events
export const decide = (db, command) => {
const todo = db.viewState("single-todo", { todoId: command.todoId });
if (!todo) throw StateChangeError.notFound("Todo not found");
const eventType = todo.completed ? "TodoUncompleted" : "TodoCompleted";
return {
events: [{ type: eventType, subject: command.todoId }],
conditions: [unchangedSince(command.todoId, todo.revision)]
};
};
// evolve(): Apply events to state
export const evolve = (state, event) => {
switch (event.type) {
case "TodoCreated":
return { ...state, todos: [...state.todos, event.data] };
case "TodoCompleted":
return updateTodo(state, event.todoId, { completed: true });
case "TodoDeleted":
return { ...state, todos: state.todos.filter(t => t.id !== event.todoId) };
}
};Not just another event store. Architectural choices that create defensible advantages no competitor can easily replicate.
"What did we know, and when did we know it?" Query both transaction time and effective time natively.
Events indexed by stream, subject, and event type — each dimension queryable bi-temporally.
Rust core + WASM components = sub-100ms write latency, 10-20ms reads, predictable performance.
Distributed tracing from day one. Jaeger-compatible. Know what's happening before users complain.
APIs IN
PURE FUNCTIONS (WASM)
STORAGE
DynamoDBKAFKA OUT
All EventsWhether you're building AI-first products, modernizing core banking, or escaping legacy systems — EvidentSource is the platform.
AI agents are becoming business actors — booking flights, processing claims, executing trades. They need decision traces before acting and complete auditability after.
Event sourcing is how modern banking should work. Working examples include high-yield savings accounts with compound interest, installment loans, and double-entry general ledgers.
LLMs have unlocked cost-effective migration from mainframes and legacy systems. Pure functions are ideal LLM targets. 10x-100x cheaper than traditional approaches.
TPS per database
Write latency
GC pauses
Deploy to your AWS account via AWS Marketplace. Your cloud, your data, open standards throughout.
Deploy locally with Docker in seconds
docker run -p 8080:8080 evidentsource/evidentsource-dev:latest Complete API reference and deployment guides
Read the DocsSLA-backed support and custom deployment
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