Comparaisons
Screaming Frog vs Online SEO Auditors: Which to Use When
A desktop crawler maps a whole site. An online auditor inspects one URL from outside. Choosing between them is really choosing which question you are asking.
Lancez un audit DomainLens frais et utilisez le rapport comme liste de priorités.
They answer different questions
The distinction is scope, not quality. A crawler tells you that 340 pages share a canonical problem. An auditor tells you what one page returns right now, from outside your network, without configuring anything.
| Desktop crawler | Online auditor | |
|---|---|---|
| Scope | Every URL it can reach | One URL at a time |
| Runs from | Your machine and IP | A server elsewhere |
| Setup | Install, configure, wait | Paste a URL |
| Site-wide patterns | Its whole purpose | Not possible |
| Sharing results | Export a file | Send a link |
| Repeatability | Manual re-runs | Trivially repeatable |
| Cost at scale | Licence, plus your time | Usually free per check |
What a desktop crawler does that nothing else can
Every one of those needs the whole graph. No single-URL tool can compute them, and no amount of checking pages individually adds up to the same answer.
- Finds orphan pages by comparing the crawl against a sitemap — only possible with the full graph.
- Surfaces redirect chains across the whole site rather than on one URL.
- Maps internal link distribution, so you can see which pages are starved of links.
- Detects duplicate title and description clusters at scale.
- Crawls staging environments behind authentication.
What an online auditor does better
It checks from outside. A desktop crawl runs from your IP, on your network, possibly through your VPN and your DNS — which is exactly the configuration least likely to reproduce what a visitor or Googlebot sees. A firewall rule blocking a datacentre range is invisible from your desk.
It is also immediate and shareable. Confirming that a fix deployed correctly is a paste-and-click, not a crawl configuration, and the result is a link a colleague can open rather than a file they have to be sent.
- Verifying a single fix after deploy, without re-crawling.
- Checking a competitor or a client site you have no access to.
- Reproducing what an outside client sees, from an outside network.
- Handing a non-technical colleague something they can run themselves.
Where each one misleads you
The most expensive of these is the first. A crawl from an IP your firewall trusts will happily report a healthy site that Googlebot cannot reach at all.
| Trap | Tool | Why it happens |
|---|---|---|
| Crawl looks clean, site is broken | Desktop | Ran from a whitelisted IP or with JS off |
| Crawl finds thousands of "errors" | Desktop | Default settings crawl parameters and filters |
| Page passes, site still fails | Online | One URL says nothing about the other 5,000 |
| Different results each run | Either | Caching, CDN nodes, or A/B tests |
| Rendering differences | Either | JS rendering off by default in many crawlers |
A workflow that uses both
The pairing is the point: the crawler finds the pattern, the external check confirms reality. For choosing between Google's own data and third-party tools see Search Console vs third-party tools , and for the free-versus-paid question see free vs paid SEO audit tools .
- 1Crawl the site to find patterns — which templates, how many URLs, what repeats.
- 2Pick one representative URL per pattern and check it from outside to confirm the crawler is not seeing a privileged view.
- 3Fix at the template level, since the crawl told you the fault is systemic.
- 4Verify the fix on that representative URL with an online check, immediately.
- 5Re-crawl only once several fixes have shipped — crawling after every change wastes hours.
How DomainLens contributes
DomainLens is the online half: it checks any URL from outside your network and reports status codes, indexability, canonical, structured data and Core Web Vitals in one pass, with a shareable result. It does not crawl a whole site, which is precisely why it complements a desktop crawler rather than replacing one. See manual vs automated audits for how the collected evidence becomes a decision.
- Is Screaming Frog free?
- There is a free tier limited to 500 URLs per crawl, with several features reserved for the paid licence. That ceiling is enough for a small site and restrictive for anything larger.
- Can an online auditor replace a crawler?
- No. Site-wide questions — orphan pages, internal link distribution, duplicate clusters — need the full graph, which a single-URL tool never has.
- Why does my crawl show no problems when the site is failing?
- Most often the crawl ran from an IP your firewall trusts, or with JavaScript rendering disabled. Verify from outside before concluding the site is healthy.
- Should I enable JavaScript rendering when crawling?
- For any site that renders content client-side, yes — otherwise the crawler reports an empty shell. It is substantially slower, so use it on a sample rather than every crawl.