Most agencies that sell technical SEO can write the audit. Far fewer can change the template, the CMS or the front-end that the audit says is broken — which is why so many technical SEO reports are still open a year later. This guide is for marketing and digital teams choosing a technical SEO partner for a corporate website: what to ask, what a good answer sounds like, and how to work together once you have chosen.
The idea
Technical SEO is engineering work. It lives in templates, content models, redirects, hosting and code. The right agency is therefore judged less by its ranking promises than by three things: whether it can implement, whether it has done so on sites like yours, and whether it protects visibility through the changes that matter most — relaunches and migrations.
Why it matters
A corporate website with thousands of pages, several languages and an enterprise CMS has technical problems that a generic SEO retainer never reaches. The cost of the wrong partner is not the fee. It is the twelve months of visibility that pass while the audit sits in a shared drive.
In practice: eleven questions to ask
1. Who will implement the recommendations?
The decisive question. If the answer is “your developers”, ask how the agency briefs them, how it verifies the fix and what happens when your developers have no time. If the answer is “we do”, ask to see it: templates they have changed, CMS configuration they own, releases they have shipped.
2. Show us a large, multilingual site you have worked on.
Ask specifically about faceted navigation, hreflang across markets, catalogue indexation and multi-site governance. An agency that has only worked on marketing sites will learn on yours.
3. How do you protect rankings during a relaunch or migration?
The right answer includes a URL inventory, a one-to-one redirect map, staging validation with a crawler, and daily monitoring after launch — in that order. If migration is described as “we’ll set up redirects”, keep looking. Compare with our website migration SEO checklist.
4. What does your audit actually contain?
You want a prioritised, buildable document: findings grouped by impact and effort, with an owner for each. You do not want a 200-page tool export with a cover page. Ask to see a redacted audit.
5. Which CMS platforms do you engineer on?
If your site is on Umbraco, WordPress, Sitecore or Drupal, the agency should know the platform’s specific traps — canonicals in variants, plugin-generated duplicates, rendering behaviour — not just SEO in general.
6. How do you approach performance?
Core Web Vitals are engineered into templates, images, fonts and delivery. An agency that answers “a caching plugin” is not a technical SEO agency.
7. Structured data: how is it maintained?
Good answer: generated from the content model so editors cannot break it, validated in Search Console. Bad answer: pasted into pages by hand.
8. What about AI search — GEO and AEO?
Search engines and AI assistants read structure, entities and clear answers. The agency should have a view on how technical SEO extends to generative and answer engines, without selling you a “GEO package” that is the same audit renamed.
9. What do you not do?
An honest technical SEO agency will say: link building, paid media, content marketing at scale — or will explain how it works alongside your partners for those. Beware of everything-for-everyone.
10. How do we measure success?
Indexation converging on the expected page count, Core Web Vitals in the green by template, errors trending to zero, rankings and organic traffic against a benchmark, and — for migrations — recovery within weeks. Agree the metrics before the work starts.
11. Who is on the team?
Ask who will actually do the work and whether they have engineered websites, not only audited them. Senior involvement is worth more than headcount.
How to work with a technical SEO agency
Give access early — Search Console, analytics, the CMS, staging and, where possible, server logs. Audits without access are guesses.
Name an owner on your side — someone who can prioritise fixes and get developer time.
Involve them before decisions — CMS choice, redesign, migration, new markets. Technical SEO is cheapest before the first wireframe.
Work in releases — findings become tickets, tickets become releases, releases are verified. Treat it like engineering because it is.
Review quarterly — the site changes, so does search. Run the audit checklist on a cycle.
What to do
Shortlist agencies that can both diagnose and build. Ask the eleven questions and listen for specifics. Prefer a partner who will be responsible for the website itself over one who will send reports about it. Then agree metrics, give access, and work in releases.
We are in the second category by design: a technical SEO agency that also designs and engineers websites, so the fixes ship. See technical SEO agency.
FAQ
What does a technical SEO agency cost?
It depends on site size, platform and whether implementation is included. A one-off audit is modest; an engagement that fixes, monitors and protects a large site through a relaunch is a larger, longer investment — and the one that pays.
Do we need an agency if we have in-house developers?
Often the best model: the agency audits, prioritises and specifies; your developers build; the agency verifies. What matters is that someone owns implementation.
Is technical SEO a one-off?
The first audit and fix cycle is the largest piece of work. After that it is maintenance — reviewed quarterly and before every significant change.
Choosing a partner? Ask us the eleven questions. We will answer with examples.