About SiteLetter

About SiteLetter, the agency-first monitoring tool.

Built for web design and dev studios with a portfolio of client sites. The weekly client report is the product. The monitoring engine exists to feed it.

The deliverable, not a dashboard screenshot

What the product produces

Every monitored site produces a branded report on the schedule the agency chooses. Their logo, their accent color, their reply-to, their agency name as the sender. The report body is theirs. SiteLetter does the work in the background.

  • A
    Branded header Upload your logo and your brand sits above the fold, in place of SiteLetter's.
  • B
    Plain-English score block Performance, Accessibility, Best Practices, SEO. Each with a trend vs the previous period.
  • C
    Uptime with context Not just a percentage. The week, with the bad day visible.
  • D
    Visual changes, AI-classified Cookie banner rotated? Auto-dismissed. Hero image missing? Flagged.

Plus SSL and domain expiry and a broken-link sweep in every report, and a portfolio overview across all client sites in the dashboard.

A
Acme Agency
Weekly Report

acme-client.com · 12 pages · 2026-04-27 - 2026-05-03

Page Scores
94 ↑ +2 Performance
100 ↑ +1 Accessibility
100 → 0 Best Practices
100 ↑ +3 SEO
Uptime
99.94% ↑ +0.03%
M
T
W
T
F
S
S
27
28
29
30
1
2
3
Visual Changes

Checked 12 pages - 2 meaningful changes

/pricing Possibly broken

Hero image area is blank - broken image placeholder visible.

/ Content update

Hero copy rewritten and a new testimonial card added.

Most monitoring tools were built for DevOps. Then a reports tab got bolted on

Most agencies run a Frankenstein stack. UptimeRobot pings the homepage. A Lighthouse runner spits out scores into a folder no one opens. A screenshot tool fires off cron jobs. And once a month, somebody on the team copy-pastes all of it into a Google Doc with the client's logo on top.

That document is the actual deliverable. It's what the retainer pays for. It's the one tangible artifact the client sees between the kickoff and the renewal call. Everything else is plumbing.

SiteLetter isn't trying to be the best fit for a fintech SRE team. It's trying to be the obvious choice for the studio that maintains thirty WordPress sites and bills a monthly retainer. See how it compares to Oh Dear, UptimeRobot, BetterStack, Checkly, and the rest.

What you can expect

01

Built for agencies, not for everyone

Feature requests that pull SiteLetter toward monitoring for everybody get turned down. If your team writes its monitoring as code and deploys it through the same pipeline as the app, you'll be happier with Checkly.

02

Self-serve, end to end

Pricing is on the pricing page. The trial is self-serve. The contact form goes to a real person, who usually replies within one business day.

03

Honest about competitors

Every comparison page has a "where the other tool wins" section, with the strengths named. If a competitor is the better fit, the comparison page will tell you.

The boring details. Important anyway

Hosted in
AWS, in the EU EU · SCCs Compute, screenshots and email run in eu-north-1 (Stockholm); the database is in eu-central-1 (Frankfurt). Uptime probes also run from the US and Singapore and return only an up/down result. Screenshots go to OpenAI in the US for change classification, under EU Standard Contractual Clauses.
Pricing
Flat $5 per site, per month All features included. 15 pages monitored per site.
Trial
14 days, no credit card Full product. Add your first site. Reports go out for real.
Launched
Late April 2026 Sole-proprietor product. Funded by revenue, not investors.
Cancellation
Anytime, in-app Two clicks: cancel and confirm. No exit survey, no upsell.
Data retention
2 years 2 years for Lighthouse scores, screenshots, and asset checks. Raw per-minute uptime check data is kept for 7 days.
Support
Email, usually within one business day For compliance or specifics, write to /contact.
Run by
Donatas Petrauskas Sole proprietorship (individuali veikla) in Lithuania.
Donatas Petrauskas, founder of SiteLetter

Donatas Petrauskas

Founder · Lithuania

I've been a web developer for about ten years now.

I built SiteLetter because the gap in this category is sharp: most uptime and developer-focused monitoring tools were built for SREs running production infrastructure, then had a "reports" tab bolted on later. In those tools the agency was a workaround. SiteLetter is the version where the agency is the customer.

SiteLetter started as a way to check whether my wife's site was up. Then I wanted Lighthouse on it. Then visual change detection. Then a weekly email so I'd stop refreshing the dashboard. The product spiraled out of that. I still run it on her site every day, and that's the first place a real bug surfaces.