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Telemetry is in early access. To turn it on for your workspace, book a call or ask in Discord.
A synthetic check sends an HTTP request to a URL on a schedule and checks the response. When runs fail, Superlog posts to Slack. When the check passes again, it replies in the same thread. Open Synthetics, under Detect in the sidebar, and click New check.

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Request

  • Method: GET, HEAD, POST, PUT, PATCH, DELETE, or OPTIONS.
  • URL: a full http or https URL. The host must resolve to public addresses.
  • Headers: up to 30. Lock a header to store its value as a secret. Secrets are encrypted, never shown again, and sent only to the URL’s host.
  • Body: for methods other than GET and HEAD.
  • Timeout: 5, 10, 20, or 30 seconds.
  • Follow redirects: on by default, up to 5 redirects. Authorization and Cookie headers are not sent to another origin after a redirect.

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Success criteria

Add up to 20 assertions. A new check starts with Status code is 2xx and Response time below 2,000 ms. Each assertion has a Severity. Fails fails the run. Degrades marks the run degraded but not failed. A run also fails when the request can’t connect or times out. Click Test to send the request once and see the response and which assertions hold.

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Schedule

  • Run: every minute, 5 minutes, 15 minutes, 30 minutes, or hour.
  • When a run fails: Don’t retry, Retry once, or Retry twice. Retries happen at once. Only the last attempt counts.

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Notifications

Choose a Slack channel. Private channels appear once the Superlog app is in them. Alert sets how many failed runs in a row start a failure: 1, 2, 3, or 5. Superlog posts once when the check starts failing, with the request, the number of failed runs, where they ran from, and the reason. It replies in the thread when a run passes again. Degraded runs don’t post. Turn off Run this check to pause it. Click Create check.

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Check page

The list shows each check’s status, latest runs, uptime over 24 hours, average duration, and last run. Click a check to see:
  • Uptime and Average duration for the last 24 hours, 7 days, or 30 days.
  • Runs over time, and Duration by phase (DNS, connect, TLS, first byte, download).
  • Latest runs. Click a run to see its assertions, timing, and response. The response is kept only for runs that didn’t pass.
  • Failures: each time the check failed, how long it lasted, and why.
Runs are kept for 30 days. Use Edit to change the check, Delete to remove it and its history, and Copy as Terraform for the Terraform provider.

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Metrics

In workspaces with telemetry, each run is also sent to your metrics: They come from the superlog-synthetics service with synthetic_check.name and synthetic_check.id attributes. Chart them on dashboards or build alerts on them, for example when the average of synthetic_check.duration is above a threshold.

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Start automations from failures

A failure message starts automations that watch its Slack channel with New message in channel or Message posted or app mentioned. Each automation runs once per failure and replies in the thread. See Triggers.

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Manage checks from an agent

The MCP server offers create_synthetic_check, update_synthetic_check, get_synthetic_check, list_synthetic_checks, and delete_synthetic_check. Use list_slack_channels for the channel and integration IDs. The same operations are in the REST API.