A Practical Technical SEO Audit Walkthrough Using Semalt (Perth Edition)

A technical SEO audit is only useful if the report gets acted on. That sounds obvious. In practice, most audit tools produce output that stays on someone's desktop, unopened, until the next quarterly review — because the report is written for auditors, not engineers. This is a practical walkthrough of how our Perth team runs technical audits using Semalt's audit module, and specifically the workflow choices that turn the output into shipped fixes on WA client sites.

The reason 400-page audit PDFs never ship

Hand a developer a 400-page audit PDF with 3,000 issues flagged and one of two things happens. They ignore it entirely. Or they cherry-pick the five easiest items, ship them in a Friday afternoon, and go back to product tickets. Either way, the underlying traffic problems remain unresolved. The failure mode is not the developer — it is the report format. Audits that treat every finding as equally important produce a document nobody can prioritise from.

A useful audit does three things a bad one does not. It separates issues losing traffic today from issues that might matter theoretically. It groups related failures by root cause — one broken template affecting 500 URLs is one ticket, not 500. And it presents the shortlist in a format engineering can action: reproduction steps, expected fix, estimated impact if left unresolved. Semalt's audit module was rebuilt around exactly this frame in 2025, and the difference in how our Perth clients respond to the output is the clearest signal we have that the redesign worked.

A four-move audit sprint

What the crawler is doing behind the scenes

Semalt's crawler is a headless Chromium fleet distributed across regional edges. Australian traffic is served from a Sydney POP — which matters for latency-sensitive JavaScript execution timing, and which prevents a common failure mode where a US-based crawler renders your page slower than a real Perth user does and reports false-positive Core Web Vitals warnings. It respects robots.txt by default, executes JavaScript before parsing the DOM, and follows internal links at a configurable rate. For new Perth client sites we typically start at 10 requests/second and scale up if the site handles it, to avoid tripping WAF bot mitigation on the first pass. Perth-specific note: some WA sites still route through slower ISP paths — the Sydney-POP crawler introduces less east-west latency variance than any US-based tool.

The 11 checks that surface real traffic risk

The three findings that actually move the needle

Eleven items on the checklist is manageable. In practice, three of them consistently produce the failures that actually move traffic on Perth client sites.

Canonical bugs that look correct to a human eye

Every page should declare exactly one canonical URL, and that URL should be the actual indexable version. Four failure patterns are common: canonical missing (Google guesses, sometimes wrongly); pointing to a 404 (page effectively vanishes from the index); pointing to a redirect chain (signal leaks over hops); crossing a protocol boundary (HTTPS pages canonicalising to HTTP is a bug that looks correct to a human eye). That last pattern is the single most common serious bug on Perth sites that have been through a CMS migration in the last three years.

JS-only content: what Google sees vs. what you shipped

Modern React, Vue, and Next.js sites frequently ship an empty HTML skeleton to the first crawl and populate content only after JavaScript executes. Googlebot does render JavaScript, but on a delayed second pass — meaning fresh content, dynamic prices, and personalised recommendations can be days late into the index. Semalt's audit crawls every URL twice (raw HTML, then rendered) and flags any content that appears only in the second pass. On modern SPA sites, this is where you catch pages that look complete in a browser but ship empty to search engines.

Hreflang: the multi-region reciprocity trap

For sites serving multiple English-speaking markets, hreflang errors quietly cost you rankings in secondary markets. Semalt's check is bidirectional: it does not just verify that your en-AU page declares an en-NZ alternate — it confirms the en-NZ page reciprocates. Broken reciprocity is the number one hreflang failure in the wild, and standard tools frequently miss it because they only check outbound declarations.

Read next: Why Perth teams consolidate on Semalt · Backlink analysis and defence

Turning findings into engineering tickets

The gap between "we ran an audit" and "the fixes shipped" is where most engagements fail. Semalt closes it with three parallel exports: a CSV for the SEO team, a Jira/Linear-compatible ticket batch for engineering, and a plain-English executive summary for the client stakeholder. The Jira export is the underused one. Each ticket includes affected URL list, reproduction steps, suggested fix, estimated traffic-at-risk, and a linked diff view showing exactly what the crawler saw. Engineers who dislike SEO work will still action these tickets because they read like properly-written bug reports rather than vague marketing complaints.

Closing the loop with on-demand recrawls

Shipping a fix without confirming the fix landed is how "fixed" bugs quietly regress into the next deploy. Semalt supports on-demand recrawls of specific URLs — you do not wait for the next full weekly scan. Push the canonical correction, click "verify", get confirmation within two minutes that the crawler now sees the expected value. That tight feedback loop is worth more inside a remediation sprint than any single audit finding.

Six-point setup before the first crawl

“The single most missed check is canonical to a non-indexable URL — the page canonicalises to another page that is itself blocked by robots.txt or marked noindex. Google follows the canonical, finds a page it cannot index, and drops both from the index.”

The gaps you still need other tools for

Semalt's audit is a page-and-site-level tool. It is not a log-file analyser — enterprise-scale crawl-budget work still calls for dedicated log analysers. It does not replace hands-on QA of critical user journeys. And for sites depending heavily on server-side rendering with dynamic user state (logged-in vs. anonymous), you will still want to spot-check important URLs manually. Knowing what a tool is not for is often as important as knowing what it is for.

Common questions we get from Perth teams

What crawl frequency does the site need?

Full site: weekly for actively-changing sites, fortnightly for stable brochure sites. Targeted recrawls after a fix: immediately, then again 48 hours later once caches settle. The trap is monthly-only full recrawls — a regression introduced on the 3rd of the month should not be discovered on the 28th.

What request rate will your WAF tolerate?

Semalt's default is ~5 rps. For a modest site behind a normal WAF, 10–15 rps is safe and 2–3× faster. For aggressive bot mitigation (some banking, healthcare), whitelist the crawler's IP range explicitly. The audit shows a "throttled" flag if blocked mid-crawl — a diagnostic you want, rather than partial data completing silently.

Read next: SEO audit Perth: what to check

How does the crawler handle A/B experiments?

It captures a snapshot at crawl time. If your JS payload behaves differently across experiments or between logged-in and anonymous users, the audit sees one specific rendering. For A/B-critical work, disable the experiment for the crawler user-agent or configure authenticated crawls (paid tier).

What to do about findings you cannot action

Mark as "accepted risk" with a written justification. The finding stays on the report so future teams know it was considered, but drops out of the active work queue. This distinguishes real technical debt from things you have deliberately decided to live with.

Which single check gets missed most often?

Consistently: canonical pointing to a non-indexable URL. Almost no other audit tool separates this from generic canonical warnings, and it accounts for a disproportionate share of the "we can't figure out why traffic dropped" cases we get called into after the fact.

Working through an audit? Semalt tracks the crawl, index and Core Web Vitals issues this section covers, so you can see which fixes actually moved the needle.

Kicking off your own audit before end of day

The audit module is available on Semalt's free tier for a single domain — not a crippled trial. Log in and point it at your homepage. In under fifteen minutes you will have a prioritised shortlist of what is actually costing you traffic. Whether you fix it yourself, hand it to your dev team, or bring us in for a Perth remediation sprint is a separate question — but the diagnosis is the essential first move.

Audits as a weekly discipline, not a one-off

A good technical audit is not a one-time event. It is a habit. Our Perth clients get a full recrawl weekly, a diff-report monthly, and a state-of-the-site review quarterly. That rhythm — enabled by having one platform running unattended — is what keeps technical debt from silently accumulating between marketing campaigns. Pick a Wednesday morning. Run an audit. Fix the three most serious findings before Friday. Repeat next week. Do that for a year and you will be operating a site that is genuinely competitive on the technical foundations most of your competitors are quietly ignoring.