How to Automate Monthly Site Health Reports for Your Agency Clients
A practical guide for UK web agencies who want to automate uptime, PageSpeed and SSL reporting without adding another dashboard your clients won't log into.
Every web agency managing maintenance retainers faces the same problem at the end of every month.
Someone — usually a developer or account manager — manually checks whether each client site is fast, whether it's been up, and whether the SSL certificate is still valid. They paste the results into a Google Doc, add the client's logo, and send it over.
It takes four to six hours per client. Across twenty retainer clients, that's up to 120 hours of non-billable work every single month.
This post explains how to automate that process entirely using a headless reporting API — so the report generates itself, arrives in the client's inbox on the first of every month, and nobody on your team had to touch it.
What Goes Into a Monthly Site Health Report
Before automating anything, it's worth being precise about what a monthly site health report actually needs to cover. Most agencies include some combination of:
Uptime — was the site available throughout the month? What was the uptime percentage? Were there any outages, and if so, when and for how long?
Performance — how fast does the site load? This is increasingly important since Google's Core Web Vitals became a confirmed ranking factor. Clients want to know their mobile and desktop PageSpeed scores, and whether they're passing the three key metrics: Largest Contentful Paint, Cumulative Layout Shift, and Total Blocking Time.
SSL Certificate — is the certificate valid? When does it expire? An expired SSL certificate takes the site offline and triggers browser security warnings. It's entirely preventable with the right monitoring in place.
These three data points answer the questions every retainer client actually cares about: is the site working, is it fast, and is it secure?
Why Dashboard Tools Don't Solve This Problem
The default assumption is that tools like AgencyAnalytics, DashThis, or Swydo handle this. They don't — not for site health specifically.
Those platforms are excellent for marketing data: PPC performance, SEO rankings, social media analytics. They pull from advertising APIs and analytics platforms.
None of them natively monitor whether your client's website was actually available last month. None of them run a live Lighthouse audit for Core Web Vitals. None of them track SSL certificate expiry.
So agencies using those tools for campaign reporting are still manually checking site health separately — often by logging into UptimeRobot, running a PageSpeed test in a browser tab, and checking the SSL manually in another tab.
The data exists. It just isn't assembled into a client-ready document automatically.
The Headless API Approach
A headless reporting API is an endpoint that accepts a URL as input and returns a complete, branded PDF report as output.
There's no dashboard to log into. No data source to configure. No connector to maintain.
You send a request with your client's URL and your agency's branding details. The API runs a live Lighthouse audit, checks the SSL certificate, pulls 30 days of uptime data, and returns a white-labelled PDF with your logo, colours and contact details throughout.
Here's what a basic API call looks like using Grevlo:
curl -X POST \
https://api.grevlo.com/v1/reports \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"url": "https://yourclientsite.co.uk",
"branding": {
"agencyName": "Your Agency Ltd",
"primaryColour": "#1E3A8A",
"logoUrl": "https://youragency.co.uk/logo.png"
}
}'
The response is a PDF. You save it, email it, or attach it to your existing reporting workflow.
Automating Monthly Delivery
The real value comes from scheduling this to run automatically on the first of every month for every client in your portfolio.
Option 1 — Cron Job
If your agency has a developer who manages the hosting environment, the simplest approach is a cron job that fires on the first of each month:
# Runs at 9am on the 1st of every month
0 9 1 * * node /path/to/generate-reports.js
The script loops through your client list, calls the Grevlo API for each URL, and emails the resulting PDFs to the relevant account manager.
A basic implementation:
const clients = [
{
name: "Client A",
url: "https://clienta.co.uk",
email: "account@youragency.co.uk"
},
{
name: "Client B",
url: "https://clientb.co.uk",
email: "account@youragency.co.uk"
}
];
async function generateReports() {
for (const client of clients) {
const response = await fetch(
"https://api.grevlo.com/v1/reports",
{
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.GREVLO_API_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
url: client.url,
branding: {
agencyName: "Your Agency Ltd",
primaryColour: "#1E3A8A"
}
})
}
);
const pdf = await response.arrayBuffer();
await emailReport(client.email, client.name, pdf);
}
}
Option 2 — Make.com
If your agency doesn't have a developer on staff, Make.com can orchestrate the same workflow without writing code.
Set up a scenario that:
- Triggers on a schedule — first day of each month at 9am
- Reads your client list from a Google Sheet
- For each row, makes an HTTP request to the Grevlo API with the client's URL
- Saves the returned PDF to Google Drive
- Sends it via Gmail to the account manager
The entire setup takes about 30 minutes and runs automatically every month without any manual intervention.
Option 3 — Zapier
Zapier works similarly to Make.com and may already be part of your agency's tech stack. Use a Schedule trigger set to monthly, connect it to a Webhook action pointing at the Grevlo API, and pipe the output to Gmail or Slack.
What the Client Receives
The output is a fully branded PDF with your agency's logo, colours and contact details on every page. The client sees your branding — not Grevlo's.
Page 1 covers the summary — uptime percentage for the month, mobile and desktop PageSpeed scores, and SSL certificate status with expiry date. Each metric has a plain English status label: Excellent, Good, Action Recommended.
If the site has performance issues, Page 2 is an Action Plan — specific Lighthouse audit recommendations in plain English. Not "your LCP score is 4.2 seconds" but "Eliminate render-blocking resources — potential saving of 1,860ms. Affected resource: /assets/main.css."
The report reads like something your account manager produced. Because the data is live — run fresh for every report, never cached — the client knows it reflects their site right now.
The Business Case
If a developer or account manager spends four hours per client per month on site health reporting at a blended billing rate of £80/hour, twenty clients costs the agency £6,400 per month in non-billable time.
Grevlo starts at £49/month for up to 15 clients. For a twenty-client agency on the Standard plan at £99/month, the return is immediate.
More importantly, the reports arrive before the client asks. Industry analysis consistently identifies poor communication as the leading cause of agency client churn — ahead of actual performance issues.
A report in the client's inbox on the first of every month is proof that you're on top of their site without them having to chase you.
Getting Started
You can try the report generation without an API key at grevlo.com — enter your agency name and a client URL and a real branded PDF generates in about 45 seconds.
Full API documentation is at api.grevlo.com/docs.
If you're managing maintenance retainers for five or more clients and want to automate the monthly site health report, the founding partner programme offers three months free access with a permanent rate lock at whichever tier suits your client volume.
Grevlo Ltd is a headless reporting API for UK web agencies. Company No. 17121751.