Simple Relay Simple Relay
llms.txt

Embedded Web UI

Inspect requests, analyze delivery attempts, and replay dead letters directly from the built-in browser dashboard.

Simple Relay packages an administrative Web UI directly inside the Go binary via go:embed. It requires zero external Node.js dependencies or separate frontend server processes.

Access the dashboard at:

http://localhost:8080/ui/

Key Features of the Dashboard

1. Real-time Delivery Log

Inspect all inbound webhooks and outbound proxy calls:

  • Chronologically sorted by monotonic ULID timestamp.
  • Filter by status (QUEUED, DELIVERING, DELIVERED, FAILED).
  • Visual latency badges showing duration per delivery attempt.

2. Payload & Header Inspector

Clicking any request opens an inspection modal showing:

  • Bit-for-bit raw incoming request headers and payload body.
  • Forwarded destination URL.
  • Upstream response headers and response body (truncated to safe size limits).

3. Attempt History & Error Traces

When upstream services fail, inspect:

  • Number of attempts made.
  • Exact backoff delay calculated with full jitter.
  • Error messages (e.g. connection refused, TLS handshake timeout, 502 Bad Gateway).

4. One-Click Request Replay & DLQ Triage

  • Replay Any Request: Click the Replay button on any row in the Requests Explorer or inside the inspection drawer to requeue deliveries immediately. This allows re-running previously successful webhooks (200 OK) against your backend after making code adjustments—see the Local Webhook Inspection Recipe.
  • Dead Letter Queue (DLQ): Deliveries that exhausted all retry policies are isolated in the DLQ view with individual and bulk replay buttons.

5. Authentication & Route Secret Masking

  • Loopback Dev Mode vs. Protected Mode: When running locally on loopback (127.0.0.1 / localhost) with RELAY_ADMIN_PASSWORD unset, the dashboard opens directly without a login prompt. When RELAY_ADMIN_PASSWORD is configured, the dashboard presents a rate-limited session login screen (relay_session HTTP-only cookie).
  • Masked Route Secrets: Inbound route signature_secret values are automatically masked in API responses (whse*****9a1b or ********). Editing a route in the UI safely preserves the existing secret unless you explicitly type a new secret to rotate it.

6. Interactive Route Configuration & Backoff Tuning

Create and modify routes dynamically:

  • Configure per-route base_backoff_ms and max_backoff_ms overrides with mode-aware pre-filling (100ms–10s for sync proxy, 5s–15m for async background delivery).
  • Toggle Retry Non-Idempotent Requests on synchronous outbound routes to permit safe POST/PATCH retries.
  • View the active backoff policy (100ms–10s or 5s–15m) directly in the Routes table Policy column.