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The Fly.io integration connects Kestrel to your Fly.io account, enabling Machine lifecycle events to trigger workflows and giving AI agents access to machine state, logs, secrets, and lifecycle actions across your apps. Unlike most integrations, Fly.io does not send outbound webhooks. Kestrel detects Machine lifecycle events by polling the Fly Machines API (https://api.machines.dev) on a configurable interval.

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Prerequisites

  • Organization Admin role in Kestrel
  • Fly.io account with app access
  • flyctl installed (to mint a token)

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Setup

1

Create an API token

Create an org-scoped token so Kestrel can read machine state and perform machine actions across all apps in the org:
A deploy token also works for a single app. Copy the token value.
2

Find your organization slug

Use the slug, not the display name. Defaults to personal.
3

Connect in Kestrel

  1. Navigate to Integrations → Fly.io in your Kestrel dashboard
  2. Click Connect
  3. Paste the API token and enter the organization slug. The token is sent as a Bearer token to https://api.machines.dev.
  4. Choose a Poll Interval — faster intervals detect incidents sooner; the minimum is 30 seconds.
  5. Save — your Fly.io account appears as connected.
No webhook setup is required — there is nothing to configure inside Fly.io. Just keep the integration connected and Kestrel will poll for Machine lifecycle events.

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How It’s Used

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In Workflows

Trigger blocks:
  • Machine Stopped — fires when a Machine transitions to the stopped state
  • Machine Failed / Crashed — fires when a Machine enters a failed state
  • Machine Started — fires when a Machine starts
  • Machine Created — fires when a new Machine is created
  • Machine Destroyed — fires when a Machine is destroyed
Filter triggers by app and event type. Kestrel polls the Fly Machines API on your configured interval to detect these transitions. Action blocks:
  • Get Machine — retrieve a Machine’s state, config, and metadata
  • Start Machine — start a stopped Machine
  • Stop Machine — stop a running Machine
  • Restart Machine — restart a Machine
  • List Machines — list Machines for an app
  • Get App — retrieve app details
  • Set Secrets — set app secrets
  • Investigate Fly.io — run an AI investigation combining machine state, logs, and lifecycle history
Fly.io app and machine selects accept template variables like {{signal.app_name}} and {{signal.machine_id}} from the trigger. Example: A workflow triggers when a Machine crashes, fetches its state and logs, runs an AI investigation, restarts the Machine, and posts a summary to Slack.

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Disconnecting

  1. Navigate to Integrations → Fly.io
  2. Click Disconnect
  3. Confirm the disconnection
This stops Fly.io polling and all Fly.io workflow triggers. You can reconnect at any time.