Keeping an API Warm with Scheduled Pings

Serverless functions and idle containers save money by spinning down when unused — and then punish the next visitor with a slow cold start while they spin back up. For a low-traffic endpoint that first-request lag can be seconds.

The Warm-Up Trick

A scheduled ping keeps the service from going fully cold. Hit a lightweight health endpoint on a regular interval and the platform keeps an instance ready, so real users get a warm, fast response.

schedule: */5 * * * *
method:   GET
url:      https://api.example.com/health

Every five minutes is a common starting point; tune it to how quickly your platform scales to zero.

Use a Cheap Endpoint

Ping something that does almost nothing — a health check that returns quickly without touching the database. The goal is to keep an instance alive, not to do real work, so the ping should be as light as possible.

Know the Tradeoffs

Warming has costs. You are paying for a little extra execution and, on some platforms, keeping an instance alive is exactly what you are billed for. For a genuinely idle service that only occasionally gets traffic, a five-minute ping is cheap insurance against a bad first impression. For steady traffic, you may not need it at all.

Watch That It's Working

Because each ping is recorded, you can confirm the warm-up is actually running and catch it if the health endpoint starts failing — which would be an early warning of trouble anyway.

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Keep your endpoints warm on a schedule. Start free with Bluejay Schedule.