otel-viewer

otel-viewer is a small, self-hosted OTLP/gRPC collector that stores traces, metrics and logs in an embedded DuckDB database and serves a web UI plus a REST query API — all in a single binary. No external services, no configuration files.

OTLP exporters ──gRPC:4317──▶ otel-viewer ──▶ DuckDB (otel-viewer.duckdb)
                                  │
                     HTTP :6666 ──┤── REST API (/api/*)
                                  └── web UI (embedded)

Forms

• Server (CLI) — cargo run, point any OTLP exporter at localhost:4317 and open http://localhost:6666. One binary, in-memory or file-backed DuckDB.
• Desktop app — the same stack wrapped in a native window (Tauri 2), with a persistent database in the OS app-data directory. See Desktop App.

Features

• Traces — waterfall view, service/error filters, span detail with attributes, events and links.
• Logs — severity filter, full-text search, trace/span correlation.
• Metrics — gauges, sums, histograms (bucket view), exponential histograms, summaries (quantiles); auto line charts per series.
• SQL console — run read-only SQL directly against the DuckDB tables, with automatic time-series charting of the result. See SQL Console & Charts.
• Storage info — file size, block usage and per-table sizes via the (i) button in the header.
• Reset — one click (well, two — it asks for confirmation) wipes all telemetry data.

Quickstart

cargo run -- --seed-demo     # UI/API on :6666, OTLP on :4317, demo data

Then open http://localhost:6666. Point your OTLP/gRPC exporter at localhost:4317 (standard OTLP port) — the locust load-test harness is a ready-made source of realistic telemetry.

Ports

The actually bound addresses are reported by GET /api/health.

Where to go next

• Architecture — how the Rust crate is put together
• REST API — endpoint reference
• SQL Console & Charts — query examples and charting rules
• Desktop App — building the Tauri shell