Technical SEO Agency vs. In-House: What B2B Companies Should Know Before Hiring

You have decided technical SEO is worth investing in. Good. Now comes the harder question: do you hire an agency or build the capability in-house? Get it wrong and you either overpay for work you could have done, or you hand a business-critical migration to someone learning on the job. This guide covers what a technical SEO agency actually does, what it costs, and how a B2B company should decide between hiring out and hiring in.

Key takeaways:

• A technical SEO agency diagnoses and fixes the crawl, indexing, speed, and architecture issues that stop good content from ranking.
• Hire an agency for specialised, high-stakes, or infrequent work; build in-house for continuous work tied to how you ship.
• The real cost of in-house is not the salary, it is the time it takes to find and keep someone who has actually done it before.
• The biggest red flag in agency selection is a reused audit template dressed up as a custom diagnosis.

What does a technical SEO agency do?

A technical SEO agency fixes the mechanics that decide whether search engines can find, read, and trust your site, the work that sits underneath content. In practice, that means auditing and repairing crawlability and indexing, improving site speed against Google's Core Web Vitals thresholds, cleaning up site architecture, and steering high-risk events like migrations.

One line a buyer should hold onto: a technical SEO agency works on the foundation a site sits on, the crawl, the speed, the architecture, rather than the content or the backlinks. If you want the full breakdown of the tasks involved, we cover the scope and pricing in technical SEO services. This guide is about who should do that work.

When do you need one?

A B2B company needs a technical SEO agency when the work is specialised, the stakes are high, or the problem is urgent and nobody in-house has solved it before. Three situations meet that bar:

1. A migration. Replatforming, changing domains, or restructuring URLs moves every ranking signal you have, and the failure mode is losing years of equity in a single deployment. Google's site move documentation runs to a long checklist for a reason. This is infrequent, high-stakes, specialised work, the exact profile that favours an agency.
2. An unexplained traffic drop. When rankings fall and the content has not changed, the cause is almost always technical, and an agency that has seen the pattern before diagnoses it faster than a generalist starting from scratch.
3. No in-house expertise. You cannot justify a full-time hire for it. That is not a failure; technical SEO is a specialism, and most B2B marketing teams are not built around it.

Agency or in-house: how to decide?

Decide by asking two questions: how specialised is the work, and how often does it recur? The answers sort most situations cleanly, and the same trade-off shows up when you weigh enterprise SEO for a large site.

The hidden cost most teams miss is on the in-house side. A senior technical SEO is hard to find and expensive to keep, and the months spent hiring are months the work does not happen. For a one-off migration, that math rarely favours building in-house. For continuous optimisation on a large, fast-moving site, an in-house owner who knows your codebase often wins.

The common answer for B2B companies is a blend: an in-house owner for day-to-day monitoring, and an agency on call for the high-stakes events.

What should you look for?

Look for an agency that diagnoses your specific site before proposing anything, and be wary of one that leads with a fixed package. Technical SEO is site-specific by nature, so a credible provider starts with your crawl data, not a brochure. The same honest-diagnosis test applies to any specialist you hire, from a content marketing agency to a technical one.

Strong signals to look for:

• They ask to see your Search Console and analytics before quoting.
• They explain findings in plain language and prioritise by impact.
• They can point to migrations or recoveries they have actually run.
• They are honest about what they cannot fix, including when the real problem is content, not technical.

What are the red flags?

The biggest red flag is a generic audit: a long PDF that could have been generated for any site, with no evidence anyone looked at yours. Others follow the same theme of effort faked rather than done.

Watch for guarantees of specific rankings, which no honest agency offers because no one controls Google's results. Watch for jargon used to obscure rather than explain, a tactic that hides a thin diagnosis. And watch for anyone who promises schema markup as a fast track to AI Overview visibility; controlled testing shows it does not reliably deliver that, and the claim signals someone selling the hype rather than the work.

Common questions about technical SEO agencies

Making the call

The decision comes down to frequency and stakes. If your technical SEO needs are continuous and tied to how you ship, build the capability in-house. If they are specialised, high-stakes, or one-off, an agency is the lower-risk choice, and a migration is almost always worth handing to someone who has done it before.

At Tenpoint Labs, we work as the technical SEO partner for B2B companies that need specialist help without a full-time hire, whether that is a migration, a recovery, or an audit to find the ceiling on everything else you publish. If you are weighing the decision, that is a conversation worth having before the next big change to your site.