Send OpenTelemetry. Query it with SQL.

$ curl -fsSL https://sigiro.com/install | sh
installed ~/.local/bin/sigiro

$ sigiro serve &
[1] 41802
listening on 4317, 4318, 9999

$ export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
$ export OTEL_SERVICE_NAME=checkout
$ npm start &
[1] 41823
checkout listening on :3000

$ sigiro status
ready · OTLP 4317 and 4318 · service checkout · 18,402 spans in 5 min

$ curl -sS -X POST localhost:9999/v1/query --data-binary \
    "SELECT span_name, count(*) AS calls FROM sigiro_spans
     WHERE service_name = 'checkout'
       AND timestamp > CURRENT_TIMESTAMP - INTERVAL '30 minutes'
     GROUP BY span_name ORDER BY calls DESC LIMIT 5"
[
  { "span_name": "POST /api/orders", "calls": 1284 },
  { "span_name": "GET /api/cart", "calls": 342 }
]

$ cat models.sql
SELECT s.span_attributes ->> 'gen_ai.request.model' AS model,
       count(DISTINCT s.span_id) AS calls, max(s.duration) AS slowest
FROM sigiro_spans s JOIN sigiro_logs l USING (trace_id)
WHERE s.service_name = 'checkout' AND l.severity_number >= 17
  AND s.timestamp > now() - INTERVAL '30 minutes'
GROUP BY model ORDER BY slowest DESC

$ curl -sS -X POST localhost:9999/v1/query \
    --data-binary "$(cat models.sql)"
MODEL           CALLS  SLOWEST
gpt-5.2-mini      246    30.0s
claude-haiku-4.6   31     2.1s

$ curl -sS -X POST localhost:9999/v1/query --data-binary \
    "SELECT trace_id, duration, status_message FROM sigiro_spans
     WHERE service_name = 'checkout' AND status_code = 2
       AND timestamp > CURRENT_TIMESTAMP - INTERVAL '30 minutes'
     ORDER BY timestamp DESC LIMIT 3"
[
  { "trace_id": "9f2c1ab4e77d", "duration": 30012,
    "status_message": "context deadline exceeded" },
  { "trace_id": "3b81fe0a2c56", "duration": 30004,
    "status_message": "context deadline exceeded" }
]