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Faable DeployAlways On & Workers

Always on and background workers

An app on Faable Deploy sleeps when no HTTP request has reached it for a while — 30 minutes on Free, 2 hours on Hobby and Pro — and wakes on the next request. That is ideal for most web apps, and wrong for two kinds of work:

  • an app that must answer instantly, every time, even the first request after a quiet night: use Always on;
  • a process that receives no HTTP at all — a queue consumer, a Discord or Telegram bot on a persistent connection, a poller, an in-process scheduler: run it as a worker.

Both are available on the Hobby and Pro plans, from the Runs as row of the app page.

Always on

An always-on app keeps one instance running with or without traffic: it never sleeps, so no request ever waits for a cold start. It is still a web app, with its URL and domains.

To turn it on:

  1. Open your app in the dashboard . On the Details tab, find the Runs as row.
  2. Switch on Always on.

The line under the row changes from “Sleeps after 2 hours without requests” to “Never sleeps”. Switch it off to let the app sleep when idle again.

Webhooks don’t need it

A webhook — Stripe, GitHub, a mail provider forwarding replies — is an inbound HTTP request, so it wakes a sleeping app by itself. Turn on Always on only if the sender expects an answer faster than a cold start of a few seconds; otherwise acknowledge the request first and do the work after, as in the Stripe webhooks guide.

Workers

A worker is an app that runs a process with no web server. It has no URL and never sleeps: Faable keeps one instance running at all times and restarts it if it crashes.

Use it for anything that works without being called: a consumer that reads a queue, a bot that holds a gateway connection (Discord, Slack Socket Mode, Telegram long polling), a scraper or a poller, node-cron or APScheduler inside the process.

Run an app as a worker

  1. Open your app in the dashboard . On the Details tab, find the Runs as row.
  2. Click Worker, and confirm.

The app keeps its code, variables, volumes and logs. What changes:

  • It stops serving HTTP: its *.faable.link URL and its custom domains no longer answer. Click Web app in the same row to switch back at any time.
  • Its start command runs as is. It does not have to listen on $PORT.
  • A new version replaces the old one by stopping it first, so two copies never run at once — what a bot with one token needs. If your worker can safely run twice for a few seconds, switch on Start the new version before stopping the old one under the row, and a deploy will not stop it until the new version is up.
  • A version is live once its process has been running for 30 seconds without restarting. A process that crashes in a loop is never promoted, and the previous version is started again.

If the build finds no web server — a Procfile with only a worker: line, or a chat bot — the app page says This app looks like a worker and offers Run as a worker.

A web app and a worker from one repository

A worker is a whole app, with one start command. If your project has both — an API and the consumer of its queue — run them as two apps: the web one as it is, and a second one switched to Worker whose start command runs the worker. Since faable.json lives at the repository root, give the worker its own start command in one of two ways:

  • a separate repository for the worker, or
  • the same repository with the worker in a subdirectory that has its own package.json (its start script runs the worker), set as the worker app’s Root Directory from the repository menu of its app page (Change root directory, which overrides a rootDir in faable.json for that app only) — and no startCommand in a root faable.json, which would apply to both apps.

Set the variables each app needs on each of them.

Compute hours

What never sleeps — always-on apps and workers — uses the project’s compute hours, measured in GiB-hours: the memory of the app’s instance × the hours it runs. A project includes 365 GiB-hours a month on Hobby (about 512 MB running all month) and 1,460 on Pro (about 2 GB). Apps that sleep don’t count.

On the Free plan

Always on and Worker show in the Runs as row, switched off, with a link to the plan page. If a project goes back to Free, its always-on apps sleep again when idle and its workers are paused — nothing is deleted — and they run again by themselves when the project is on a paid plan.

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