Config-driven
A single JSON document defines steps, sections, branching rules, validation, and progress. Nothing is hardcoded in the UI.
Demo · Adaptive Workflow Engine
Config-driven multi-step flows
with resumable sessions.
A small, deployable reference architecture for behavioural research instruments. FastAPI engine + Next.js renderer. The instrument is authored as JSON. The engine evaluates branching, persists sessions, and exports flat results.
Adaptive branching
Per-step show_if conditions are evaluated against the live answer set. The path adapts as the respondent moves through the flow.
Resumable sessions
Session state is persisted server-side. Refresh the browser, switch devices, or come back later — the engine drops you back at the right step.
Clean export
Flat JSON export of every answer plus session metadata. The same plumbing extends to SPSS or CSV without touching the engine.
Architecture
backend/app/ engine/ # pure step-resolution + branching + validation storage/ # SQLAlchemy models + repository routes/ # FastAPI endpoints config/ # study JSON + loader schemas/ # Pydantic wire schemas frontend/src/ api/ # typed fetch client engine/ # shared workflow types components/ # question renderers + chrome app/ # Next.js routes