State Transition Capsule

Local state forensics

Find the first state change that broke the second run.

Capture named snapshots and domain events. Redact sensitive fields at the source. Compare a known-good run with the failure—without uploading either one.

Open the workbench
  • Local only
  • JSON portable
  • No effect execution
Illustrated diagnostic instrument feeding two state cartridges into one divergence trace
Two recorded runs. One exact divergence.

Bench 01 / compare

Divergence workbench

Load a known-good capsule and the run that drifted. Files stay in this tab by default.

Ready offline

Known-good run

No capsule loaded

Changed run

No capsule loaded

Awaiting two capsules

Use your exported JSON files or load the example to see the first divergent field.

A small evidence format

Instrument the state boundary, not the whole session.

Capsules capture only the state and domain events you declare. That makes failures portable, reviewable, and safe to inspect on a second machine.

  1. 01

    Record

    Wrap the point where durable state changes. Set a transition limit for bounded evidence.

  2. 02

    Redact

    Replace exact or wildcard paths before anything reaches the capsule.

  3. 03

    Compare

    Align snapshots in order and stop at the first changed JSON path.

0.1.0 / zero runtime dependencies

A narrow API for evidence you own.

ESM, CommonJS, and TypeScript declarations ship together. No telemetry. No remote runtime.

Read the complete API guide
capture.ts
import { createRecorder } from "state-transition-capsule";

const run = createRecorder({
  name: "report / run 2",
  initialState,
  redact: ["auth.token", "**.password"],
  retention: { maxTransitions: 100 }
});

run.record(event, nextState);

Capsule Studio / one-time purchase

Keep a local case history.

The open package and viewer handle the complete capture-and-compare workflow. Studio adds saved comparison labels and local history for teams who revisit incidents.

$39 one time · per user

  • Saved local comparison history
  • Named incident labels
  • Future Studio adapters
Buy Capsule Studio

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License channel

Studio locked

The free comparison bench remains fully available.