Architecture

Layer diagram

Attestia.App (WinUI 3)
  Dashboard - Intents - Proofs - Reconciliation
  Compliance - Events - Settings
Attestia.ViewModels (CommunityToolkit.Mvvm)
Attestia.Client          |  Attestia.Sidecar
  HTTP SDK               |  Node.js process manager
Attestia.Core
  Domain models - Enums - Shared types

NuGet packages

Package	Description
Attestia.Core	Domain models — Intent, MerkleProof, ReconciliationReport, Money, ComplianceFramework, DomainEvent, and more
Attestia.Client	HTTP client SDK with eight typed sub-clients: Intents, Proofs, Reconciliation, Compliance, Events, Verify, Export, and Public
Attestia.Sidecar	Node.js process manager — port discovery, health polling, auto-restart, clean teardown

Client sub-clients

The AttestiaClient facade exposes eight sub-clients:

Sub-client	Purpose
Intents	Declare, approve, reject, execute, verify intents; list and get by ID
Proofs	Merkle root info, attestation proof packages, proof verification
Reconciliation	Three-way reconciliation, attestation records
Compliance	Framework listing, scored compliance reports
Events	Global event stream and per-stream event queries (paginated)
Verify	Global state hash computation and replay verification
Export	NDJSON event export and full state export
Public	Public verification endpoints — state bundles, verifier reports, consensus, public proof verification, compliance summaries

All HTTP calls use envelope-based responses (AttestiaResponse<T>), automatic retry with exponential backoff on 5xx errors, and CancellationToken support.

ViewModels

ViewModels inherit from ViewModelBase, which provides:

• IsBusy / ErrorMessage / IsEngineOffline observable properties
• RunBusyAsync wrapper that catches exceptions and sets human-readable error messages
• Automatic detection of connection failures (sets IsEngineOffline for UI indicators)

Sidecar

The Sidecar manages the Node.js backend as a child process:

• Finds a free port automatically (or uses a configured fixed port)
• Sets PORT and NODE_ENV=production environment variables
• Polls /health at a configurable interval (default 5 seconds)
• Auto-restarts if the process dies (configurable via AutoRestart)
• Kills the entire process tree on dispose
• Emits StatusChanged events: Stopped, Starting, Running, Degraded, Crashed, Stopping, Error

await using var sidecar = new NodeSidecar(options, locator, logger);
await sidecar.StartAsync();
Console.WriteLine($"Backend ready at {sidecar.BaseUrl}");

The NodeBundleLocator searches for node.exe in three locations: a configured path, the bundled assets/node/ directory, then the system PATH.