Slack alerts when your service goes down

Your API can look fine on your laptop and still be down for customers — deploy stuck, DNS wrong, TLS expired, region outage. External uptime monitoring hits your public health URL from the internet. Slack is where indie teams already live, so routing owner alerts there beats refreshing a dashboard.

StillOnline sends plain-text messages to a Slack Incoming Webhook you control. No Slack App review and no global bot token on our servers — only your webhook URL stored in account settings.

Quick answer

StillOnline posts owner alerts to a Slack channel you choose via an Incoming Webhook you create in your workspace—paste the URL in account settings and enable Slack alerts. On Free, pick Slack as your single owner channel; on Pro / Ultimate, combine email, Telegram, and Slack. Messages cover check down (throttled to once per 15 minutes while down), recovery, and 24h stability—after you add an HTTP check (health check quickstart).

What you get in Slack

StillOnline posts owner alerts into the Slack channel you bound when creating the Incoming Webhook—formatted as a Block Kit card with probe details and links back to your project. These are not @channel mentions unless your workspace rules add them; they are the same down / recovery / 24h events you can get in email or Telegram.

After a check is configured, StillOnline can post to your channel when:

Each message is a Block Kit card: project, check, URL, last probe (HTTP code, latency, method), trigger rule, timestamp, and buttons for status page and dashboard.

StillOnline does not post every failed probe — only status transitions and the stability milestone.

Before you connect Slack

Plan for about ten minutes: create a channel, create a Slack app with a webhook, then paste the URL in StillOnline. You will need admin or app-install rights in the workspace where alerts should land.

1. A StillOnline account — sign in (Google or GitHub).
2. A project with an HTTP check — URL that should return 2xx (see health check quickstart).
3. Permission in Slack to create channels and add an app / incoming webhook to your workspace.

On Free, pick one owner alert channel: Email, Telegram, or Slack. On Pro / Ultimate, you can enable email, Telegram, and Slack together (Pricing).

First — create a Slack channel (before api.slack.com)

When you click Add New Webhook to Workspace, Slack asks you to pick an existing channel. If you do not have a dedicated alerts channel yet, create one before Part A.

Step 0 — Create a notification channel

In Slack (desktop or browser), in the workspace where alerts should land:

1. In the sidebar under Channels, click + (or Create a channel).
2. Name — we recommend stillonline-alerts (shown as #stillonline-alerts). #alerts, #incidents, or #uptime work too — the channel must exist before you configure the webhook.
3. Visibility: Public for a small team; Private if only a few people should see outages.
4. Optional description: e.g. “StillOnline owner alerts: check down, recovery, 24h uptime”.
5. Click Create / Create channel.

Invite teammates who should see alerts. Do not archive this channel later — the webhook stops delivering if the channel is archived.

Part A — Create a Slack Incoming Webhook

Step 1 — Open Slack API apps

Go to api.slack.com/apps and sign in to the workspace where you want alerts.

Step 2 — Create an app

1. Click Create New App.
2. Choose From scratch.
3. App Name: e.g. StillOnline Alerts.
4. Workspace: select your team → Create App.

Step 3 — Enable Incoming Webhooks

1. In the left sidebar, open Incoming Webhooks.

2. Turn Activate Incoming Webhooks to On.

3. Click Add New Webhook to Workspace at the bottom.

4. Pick the channel from Step 0 (e.g. #stillonline-alerts) → Allow.

5. Copy the webhook URL — it looks like:

   https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX

Keep this URL secret. Anyone with it can post to that channel.

You can mute the channel in Slack if you only want @mentions on down events (client notification settings).

Part B — Connect the webhook in StillOnline

Step 5 — Open owner notification settings

1. Go to https://stillonline.tech/app/settings.
2. Scroll to Owner notifications.

Step 6 — Paste the webhook and enable Slack

1. In the Slack section, paste the Incoming Webhook URL into the field.
2. Check Slack alerts.
3. On Free, under Free: one channel, select Slack (if you use email today, switching to Slack disables email alerts until you change it back or upgrade).
4. Click Save.

If the URL is invalid (not https://hooks.slack.com/services/...), the form will reject it.

Step 7 — Confirm a check exists

In Projects, open your project and ensure an HTTP check points at your live URL (e.g. https://api.example.com/health). The worker probes on your plan interval (5 minutes on Free).

Part C — Verify alerts work

Step 8 — Trigger a test down (carefully)

Pick a non-production check or a temporary URL:

1. Edit the check URL to something that returns 500 or is unreachable, or pause your service briefly in a staging environment.
2. Wait for two failed probe cycles (up to ~10 minutes on a 5-minute interval).
3. You should see a Slack OUTAGE · StillOnline card with probe details and status/dashboard buttons.

Step 9 — Confirm recovery

Restore the correct URL or service. After the next successful probes, you should get RECOVERED · StillOnline.

Do not rely on Slack alone for compliance — keep your status page linked for customers.

Slack vs email vs Telegram

All three channels receive the same StillOnline owner events; Slack is throttled on down like email (at most once every 15 minutes), unlike Telegram which repeats every check interval. Pick one on Free or enable several on Pro.

Subscribers on the public status page still get email when they subscribe with Google — that is separate from owner Slack alerts.

Limits and troubleshooting

If messages never arrive, the webhook URL, channel archive state, and Free-plan “one channel” setting cause most cases—not a missing Slack integration on StillOnline’s side. Use the table as a checklist.

StillOnline logs delivery in the database (NotificationLog, channel SLACK) for support debugging.

Related guides

• Telegram owner alerts — mobile DMs via the StillOnline bot.
• Health check URL quickstart — create the URL Slack will watch.
• Best uptime monitoring for indie SaaS 2026 — how we compare to other tools.
• MCP for agents — recreate checks from Cursor on Pro.

FAQ

Do StillOnline Slack alerts require a paid Slack workspace?

No. StillOnline uses standard Incoming Webhooks, which work on free Slack workspaces. You need permission to create an app and add a webhook to a channel (for example #stillonline-alerts). Setup steps are in this guide; monitor a URL from health check quickstart first.

Can StillOnline owner alerts go to a Slack DM?

StillOnline is designed for a channel webhook from Add New Webhook to Workspace. Some teams point the webhook at a private channel; DMs are not the default path. For mobile DMs to one person, use Telegram alerts from the StillOnline bot.

Does StillOnline support Slack OAuth or slash commands for owner alerts?

No. StillOnline owner alerts use Incoming Webhooks only—paste your workspace webhook URL in settings. OAuth apps and slash commands are not part of the product today.

Does StillOnline post to Slack on every failed probe?

No. StillOnline alerts on down after consecutive failures (not every timeout). While down, Slack down alerts are throttled to once per 15 minutes per owner; recovery and 24h messages are separate. Brief transient failures may show degraded on your status page without a down post.

Can I use StillOnline Slack and email together on Free?

No. Free = one owner channel (email, Telegram, or Slack). Pro / Ultimate allow email + Telegram + Slack together—Pricing. Compare channels in Telegram guide.

How should I store the StillOnline Slack webhook URL?

Treat it like a password—anyone with the URL can post to that channel. Rotate by creating a new webhook in Slack and updating StillOnline settings. Leaving the field blank on save keeps the previous URL unchanged.