A Website Monitoring Checklist for Agencies

If you run sites for clients, "we'll notice if something breaks" is not a monitoring strategy. This is a practical checklist of what to watch on every client site, how often to check it, and who should be alerted, so nothing slips through the cracks between one client call and the next.

Deltio covers most of this checklist automatically across all your client sites and sends alerts to Slack. From £20 a month.

Every agency has a version of the same near-miss story: a change nobody caught until a client asked about it. The fix isn't working harder or checking more often by hand. It's turning the vague intention to "keep an eye on things" into a defined list of signals, each with a cadence and an owner. Here's that list.

Indexing and crawlability

These decide whether pages are even in the race. A single silent change here can pull a page, or a whole section, out of Google.

• noindex tags. Watch for pages that become noindexed, in both the meta tag and the X-Robots-Tag header. Check daily.
• robots.txt. One edited line can block crawling of an entire site. Watch for any change. Check daily.
• Canonicals. Flag canonicals that start pointing to a different page or a 404. Check daily.
• Sitemap. Track URLs added and removed. A sudden drop usually means content is disappearing. Check daily.

On-page SEO

The signals that decide how well an indexed page competes.

• Title tags. Watch for titles that change unexpectedly or break (the classic "undefined"). Check daily.
• Meta descriptions. Flag pages that lose or change their description. Check daily.
• H1 tags. Watch for missing or changed H1s after a template update. Check daily.
• Hreflang. For multilingual sites, watch for broken or removed hreflang. Check daily.

Availability and performance

A site that's down or slow loses rankings and conversions at once.

• Uptime. Alert the moment a site becomes unreachable. Check continuously.
• Response time. Watch for sustained slowdowns. Check continuously.

Security and domain

The infrastructure that can take a client offline overnight.

• SSL certificate. Alert at least thirty days before expiry. Check daily.
• Domain expiry. Alert well before the registration lapses. Check daily.

Tracking and marketing tags

The silent failures that break reporting without any visible error.

• Analytics and tags. Watch for GA4, GTM or the Meta Pixel disappearing or changing. Check daily.
• Consent and cookie banners. Flag when a consent management setup changes, since it affects both compliance and data. Check daily.

Who gets alerted

A checklist only works if the right person hears about it fast.

• Route by client. Each client site's alerts go to the channel or people who own that account, so nothing sits in a shared inbox nobody reads.
• Use Slack, not just email. Alerts you see in the flow of work get acted on. Alerts buried in email get missed.
• Keep it plain. "The sitemap for example.com dropped 30 URLs today" beats a cryptic status code.

How to run this without doing it by hand

Working through this checklist manually across ten client sites, every day, is a full-time job nobody has. The point of the list isn't to do it by hand. It's to make sure your monitoring actually covers all of it.

Deltio automates most of this checklist: indexing signals, on-page SEO, sitemap changes, uptime, SSL and domain expiry, and marketing tags, across every client site from one account, with alerts routed to Slack per client. You set it up once in a couple of minutes per site, and the checklist runs itself.

Add your first client site, connect Slack, and Deltio starts working through the list the same day. Start your 14-day trial and turn "we'll notice" into "we already know."