Case Study: Migrating a WordPress Site to a Headless ACF Build

[CLIENT OR ANONYMISED DESCRIPTION] came to us with a mature WordPress website, [NUMBER] pages and [NUMBER] structured content records deep. The site still worked well as an editorial system, but the frontend had become difficult to extend, inconsistent across templates, and increasingly fragile to touch.

We migrated the site to a headless architecture. WordPress and Advanced Custom Fields kept managing structured content, while a separate frontend application took over delivering the public website. We weren’t chasing headless for its own sake, the goal was to improve [VERIFIED BUSINESS OR TECHNICAL OBJECTIVES] without disrupting search visibility or the editorial team’s day-to-day.

The client

[CLIENT] is a [SECTOR AND SIZE DESCRIPTION] serving [AUDIENCE OR GEOGRAPHY]. The website supports [PRIMARY JOURNEYS: enquiries, resources, locations, products, membership or another verified purpose], and content is managed by [NUMBER OR TEAM DESCRIPTION], updated [FREQUENCY].

Add one short sentence here on why the website matters commercially, for example “the site is the primary source of qualified enquiries” or “the resource library supports customers and cuts down repeated support requests.” Only use a statement you can actually verify.

The challenge

The existing site had grown over [TIME PERIOD], with new requirements bolted on through [THEMES, PLUGINS OR CUSTOM CODE] along the way. That left several connected problems:

• [VERIFIED frontend or component limitation].
• [VERIFIED publishing or content-model problem].
• [VERIFIED performance or Core Web Vitals issue].
• [VERIFIED integration or maintenance risk].
• [VERIFIED SEO or migration constraint].

The team wanted [TARGET OUTCOME], but a visual redesign on its own was never going to fix content and architectural constraints that deep.

Why headless WordPress was the right fit

WordPress was still familiar to the editors, and it held valuable structured content. Replacing the CMS entirely would have added training and migration risk for no clear business gain. Decoupling the frontend let the team keep its editorial workflow while we rebuilt the public experience as a component-based application.

The decision was justified by [VERIFIED REASONS: multi-channel content, complex frontend interactions, shared design system, product integration or performance requirements]. For a simpler marketing site, I’d normally reach for a conventional custom WordPress theme first, headless isn’t the default.

That distinction matters. We chose headless because it solved defined constraints here, not because it sounded more modern on a case study.

The target architecture

Include a simple architecture diagram when this goes live, content moving from WordPress through the API to the frontend, plus whichever external services own forms, search or authentication.

Discovery and migration planning

The project started with a full inventory: URLs, templates, content types, fields, media, redirects, integrations, editorial workflows. Every item got assigned one of four outcomes: retain, improve, merge or retire.

That discipline stopped the new site from just reproducing the old complexity under a new coat of paint. We also captured baseline data before development started:

• Top organic landing pages.
• Indexed URLs and known coverage issues.
• Existing redirects and high-value backlinks.
• Core Web Vitals for representative templates.
• Conversion events and form completion.
• Known crawl, canonical and structured-data issues.

Document the dates and tools used for every baseline metric. A result with no measurement window attached is hard to evaluate honestly, so don’t skip this.

Designing the ACF content model

Instead of handing editors an unrestricted blank canvas, the new CMS used structured fields aligned to the design system. Content types included [VERIFIED TYPES], with reusable fields for [VERIFIED EXAMPLES].

The model kept content separate from presentation. Editors controlled the information and approved variants, the frontend controlled spacing, responsive behaviour and accessibility. That cut down layout drift and made components genuinely reusable across the site.

We tested the content model against real edge cases before migration, not just the happy path. Long titles, missing images, unusual data combinations and legacy content all exposed assumptions that a perfect sample page would have hidden completely.

Building the frontend

The frontend was built around reusable components, shared design tokens and typed content contracts. We built representative pages first, to test the hardest content combinations, rather than starting with the homepage because it’s the obvious one.

We added preview support, error handling and fallback behaviour, so editors could review unpublished changes, and the public site would fail safely if an API request ever came back empty.

Accessibility and performance checks were built into the component workflow itself, so quality was repeatable rather than something checked for at the end, after every page had already been assembled.

Protecting SEO during migration

The migration plan included the following controls:

• Exported and reviewed every indexable legacy URL.
• Preserved strong URLs wherever possible.
• Created one-to-one redirects for merged or retired pages.
• Migrated page titles, descriptions, canonical rules and social metadata.
• Validated headings, internal links, structured data and image alt text.
• Generated XML sitemaps and checked robots directives.
• Tested status codes and rendered HTML before launch.
• Monitored Search Console, analytics and server errors after release.

Avoid claiming rankings were “protected” unless the evidence actually backs that up. A safer statement rests on measured organic clicks, impressions, indexed pages and landing-page performance over a defined window, numbers, not adjectives.

Quality assurance and launch

QA covered content parity, responsive layouts, keyboard navigation, forms, analytics, redirects, API failures and performance across representative templates. We launched through [VERIFIED RELEASE METHOD], with a rollback plan and named owners for WordPress, frontend hosting and external services.

The launch checklist should also record:

• DNS and SSL ownership.
• Cache invalidation and publishing triggers.
• Error-monitoring destinations.
• Backup and restoration ownership.
• Form and transactional-email tests.
• Search Console and analytics access.
• A named contact for the first post-launch review window.

The results

Replace this section with verified evidence.

Add a client quotation only after approval:

“[VERIFIED QUOTE ABOUT THE OUTCOME, EDITOR EXPERIENCE OR DELIVERY].”

A useful results section covers trade-offs as well as improvements. If the new architecture added deployment complexity or changed how editors worked day to day, say so, and explain how it was managed.

What we learned

• Headless is valuable when it solves a defined product or publishing constraint.
• Content modelling should happen before frontend components are finalised.
• Preview and editorial workflows deserve the same attention as public performance.
• Migration success depends on URL and content discipline, not only technical deployment.
• Clear ownership across CMS, frontend and integrations is essential after launch.
• Baseline evidence should be captured before development begins, not reconstructed afterwards.

Was headless worth it?

For [CLIENT], the architecture was justified because [VERIFIED SUMMARY OF VALUE]. We kept WordPress where it was strong and replaced the frontend where the organisation needed more control. What came out the other end wasn’t just a new website, it was a clearer content and delivery system underneath it.

Next step: Considering a WordPress-to-headless migration? Trisec can audit the current content model, frontend constraints, SEO risk and operational ownership before recommending whether headless ACF is the right move.

Frequently Asked Questions

Can a headless migration preserve existing rankings?

It can preserve and even improve search performance when valuable content, URLs, metadata, rendered HTML and redirects are all handled carefully. No agency should guarantee rankings though, and the launch needs close monitoring regardless.

Do editors still use WordPress?

Yes. WordPress stays the editorial backend. The project has to provide preview and publishing workflows that actually make sense for the content team using them day to day.

Should every WordPress redesign become headless?

No. A conventional custom theme is simpler and more cost effective for most marketing websites. Headless earns its place when it solves a specific frontend, channel or product requirement, not as a default upgrade.

What facts must this case study include before publication?

Client permission, project dates, actual scope, architecture, baseline metrics, result metrics, measurement windows and a truthful description of Trisec’s responsibilities.