How it works

Nelkap calls your app, and your app runs the code.

Nelkap comes to your app

Your workflows run in your app, on your servers. When a run is due, Nelkap calls your endpoint. The SDK answers at once, then runs the workflow in the background.

Every step is saved

Each time a step finishes, the SDK sends its result to Nelkap. Nelkap keeps it with the run.

A run picks up where it stopped

Each call runs your workflow from the top, along with the steps already saved. A saved step returns its result at once, without running again. The code moves past them until it reaches a new step, and carries on from there.

Here is what happens to the onboardUser workflow from the quickstart:

1. Nelkap calls your app. profile runs and is saved. The sleep is saved, and the call ends.
2. A day later, Nelkap calls again. profile returns its saved result. The sleep is over. welcome runs, and the run completes.

Pauses end the call

A sleep or a wait ends the call, and your app is free. Nelkap calls again when the time is up, or when the event arrives.

Nelkap keeps runs going

While a run executes, the SDK tells Nelkap every minute that it’s still working. If that signal stops for five minutes, during a crash or a deploy, Nelkap calls your app again. The run picks up from its last saved step.

Run statuses

Status	Meaning
Pending	Due, and waiting for its turn.
Ready	On its way to your app.
Running	Your app is running it.
Sleeping	Paused until its time is up.
Waiting	Paused until its event arrives.
Completed	Your workflow finished.
Failed	Your workflow threw an error, or Nelkap stopped it. The reason shows on the run’s page.
Canceled	Canceled before it could finish.