Free tool, no signup
Free Sitelist Checker
Drop your sitelist. We score every domain on quality: ad density, ad experience, traffic and SSP coverage, and whether it's a recognised premium publisher. You see which ones to keep, and which ones to cut.
Free · Validate up to 3,000 domains
180,000+ premium domains indexedCSV & PDF exports
Lists are limited to 3,000 domains maximum.
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What this tool checks
Quality and supply signals, on every line of your list.
- Ad density. How much of the page is advertising relative to content. It's the single most reliable indicator of a site built to serve ads rather than to attract an audience, and it's the check that separates a publisher from an arbitrage operation. A domain can pass every brand safety filter and still be almost entirely advertising.
- Ad experience signals. Refresh behaviour and slot volume alongside density. Ads that reload on a timer or stack on scroll inflate impression counts on a single visit, which is what turns bought traffic into a margin for the site operator and wasted budget for you.
- Traffic and ad volume. Domains flagged as low ad volume carry too little activity to be worth a line on your list. They rarely deliver scale, and they add noise to reporting without adding reach.
- SSP coverage. Which premium platforms carry a domain, across 5+ premium SSPs. A domain nobody can buy at scale is a line item you'll never activate, and coverage tells you whether your list is actually addressable.
- Recognition against a premium index. Each domain is checked against an index of more than 180,000 premium domains. Presence tells you the site is a known, established publisher. Absence isn't a verdict on its own, but an unrecognised domain carrying significant ad volume is worth a closer look.
How to read the results
A single weak signal is a question. Two together are usually an answer.
- High density, unrecognised domain. The classic made-for-advertising profile: a site built to hold ad slots apart, monetising traffic it acquired rather than earned. Cut it.
- High density, established publisher. Not the same problem. This is a real publisher over-monetising, which hurts performance for mechanical reasons but isn't arbitrage. Worth a conversation about placement rather than an exclusion.
- Aggressive refresh behaviour. One visit counted several times. Your impression numbers look healthy and your outcomes don't follow. Treat it as a density problem regardless of what the ratio alone says.
- Low ad volume. The domain is clean but thin. Keep it only if it serves a specific editorial or contextual purpose, otherwise it dilutes the list without contributing delivery.
- Thin SSP coverage. A quality domain your platforms barely reach. Before dropping it, check whether it can be picked up through another supply path, or replace it with a comparable domain that is broadly available.
- Clean throughout. Keep it, and write down that it passed. Domains that clear consistently are worth building a list around instead of rediscovering them every quarter.
Why sitelists go stale
Most lists are built for a brief, applied, and forgotten. Three months later a similar brief arrives and the work restarts from nothing, minus everything the last campaign taught you.
Sites change in the meantime. They get sold, redesigned, loaded with additional ad slots, or quietly lose the audience that justified including them. Supply coverage shifts too: a domain that was widely available last quarter may no longer be carried by the platforms you buy on. A list assembled six months ago describes a web that has moved on.
Re-checking a list takes a few minutes and is the cheapest quality work available to a buying team.
For the full method, see our guide on how to build a sitelist for programmatic deals.
Questions people actually ask
- Is the sitelist checker free?
- Yes, and there is no signup. You can validate up to 3,000 domains per list, with a daily limit on the number of validations.
- What does the tool check on each domain?
- Domain quality and supply signals: ad density, meaning how much of the page is advertising relative to content, ad experience indicators such as refresh behaviour, traffic and ad volume, and SSP coverage showing which premium platforms carry the domain. Each domain is also checked against an index of more than 180,000 premium domains, so you can see which lines in your list are established publishers and which are unrecognised.
- What is a good ad density score?
- There is no universal threshold, because it depends on the format and the vertical. What matters is relative: within your own list, the domains at the high end of the density range are the ones worth examining first. Manual review of a handful of outliers tells you where your line sits.
- What does Low Ad Volume mean?
- It means the domain shows too little advertising activity and traffic to contribute meaningful delivery. The site may be perfectly legitimate, but as a line on a sitelist it adds reporting noise rather than reach, so keep it only when it serves a specific contextual purpose.
- Why does SSP coverage matter on a sitelist?
- A domain you cannot buy is not inventory. SSP coverage tells you which premium platforms carry a domain across 5+ premium SSPs, so you can tell the difference between a list that looks good on paper and a list that will actually deliver once it is attached to a deal.
- Can I export the results?
- Yes, in CSV and PDF. The PDF report includes the quality breakdown and SSP coverage across your list.
- What is not covered by the free version?
- The free checker focuses on auditing a list you already have. Matching low-quality or missing domains with premium alternatives, and the activation of a validated list into live deals, are part of the full product rather than the free tool.
- How often should I re-check a sitelist?
- After each significant campaign rather than on a fixed calendar. Sites change ownership, redesign or add ad slots, supply coverage shifts, and campaign results tell you which domains actually delivered, which is information worth folding back into the list.
- What is the difference between a sitelist and a blocklist?
- A sitelist names what is allowed and excludes everything else by default. A blocklist names what is forbidden and allows everything else. The first protects quality at the cost of reach, the second protects reach and is always one step behind new domains.