How to choose a web agency in the UK in 2026

The standard way of choosing a web agency is to send an RFP to four or five shops, compare the responses, review portfolios, take some intro calls, and pick the one whose pitch deck felt most polished and whose number sat in the middle. It's the way most procurement teams have been taught to run any vendor selection, and it produces the wrong result for web projects more often than it produces the right one.

The reason is that portfolios and price don't predict project success. The portfolio tells you what the agency was capable of when they had their best people on a project with a generous budget and a cooperative client. The price tells you what the commercial team thinks they can win the work for. Neither tells you who you'll actually be working with on Tuesday morning in week eight when something has gone wrong.

This guide is intended to give you everything you need to choose well — even if the agency you end up choosing isn't us. Read it end-to-end if you're about to start the selection process. Skim the questions list at the end if you're already in conversations and want to sharpen your evaluation.

Define what you actually need: the four types of web agency

The UK market has roughly four kinds of agency, and they're often pitched as if they're interchangeable. They aren't.

Full-service agencies offer design, development, strategy, content, and ongoing support under one roof. Their value is one point of accountability and a coherent thread from brand through to implementation. Their limitation is that they have to be reasonably good at many disciplines rather than excellent at one. They suit clients who want a primary partner across the full lifecycle of the site and don't want to coordinate specialists themselves. Budgets at the upper end of the market.

Design-led agencies are focused on brand, visual identity, and user interface. Engineering is usually present but secondary — they'll partner with a development shop or hand off a Figma file for someone else to build. They suit clients whose primary challenge is brand positioning and visual differentiation, and whose technical requirements are modest. Be careful: a design-led agency selling a complex build will often subcontract the engineering, and the seams show.

Development-focused agencies are the inverse. They build complex custom products, integrate with legacy systems, and write code at a level that brand-led shops can't match. They tend to be weaker on visual design and content. They suit clients who already have a strong brand system and a design partner, or whose primary challenge is technical (performance, scale, integration depth).

Platform specialists focus on a single platform — Shopify, WordPress, Webflow, Sanity. They go deep on the platform's idioms, plugins, and limitations. They suit clients whose project clearly belongs on that platform, or who want the productivity and ecosystem benefits of a popular stack. They struggle when the project pushes the platform's boundaries.

Before you talk to any agency, get clear on which of these you actually need. A common failure mode is approaching a development-focused agency for a brand-led project, or vice versa, and being disappointed that the work doesn't reflect the strengths you didn't ask for.

Treat agency evaluation like hiring — because it basically is. Source: Pexels

The eight things to evaluate

Once you've narrowed by type, here's how to evaluate the agencies in the shortlist.

Portfolio relevance: same industry, or same problem type?

Most buyers default to looking for industry experience. "Have you done a fintech site? Have you done healthcare?" That's the wrong filter most of the time. Industry experience matters for compliance-heavy verticals — finance, healthcare, gambling, defence. It barely matters anywhere else.

What matters more is problem-type experience. Have they done a re-platforming with a tight no-downtime window? Have they done a multilingual, multi-region rollout? Have they done a content-heavy site with editorial workflows? Have they done a high-traffic e-commerce build with subscription complexity? An agency that has solved your problem type in another industry will outperform one that has solved a different problem type in your industry.

Look at the portfolio with that lens. Ask: what's the hardest thing they've shipped that resembles what we need?

Team structure: who actually works on your project?

This is the single most important question and the one most agencies are slipperiest about. Ask explicitly: who will be on this project? Are they staff or contractors? Are they the same people pitching us? What percentage of their time will be on our work, and what percentage on other accounts simultaneously?

A reasonable answer to the last question is 25–50% across two or three concurrent projects. A red flag is anything that sounds like "we have a pool and we'll allocate based on availability." That means you'll get whoever isn't busy in the week your work hits the queue.

Ask if the senior who pitched you will be in the project from week one to launch. The honest answer in a small agency is usually yes. The honest answer in a large one is usually no, and the way it's phrased — "I'll be staying close to the work and supporting the team" — should tell you that someone you haven't met yet will be doing the actual delivery.

Process transparency

Ask them to walk you through their delivery process on a ten-minute call. Discovery, design, build, QA, launch, post-launch. If they can't do it without a deck, that's a flag. If the answer is heavy on jargon and light on specifics, that's a flag. If the process they describe doesn't have a discovery phase, that's a major flag — it means they're going to start building before they understand the problem.

Good agencies have a process they've genuinely sharpened over years. They can describe it in plain English, name the artefacts that come out of each phase, and tell you what the client's role is at each stage.

Technical credibility

This is where a lot of buyers undersell themselves. You don't need to be a developer to ask sharp technical questions. You need a short list of the questions that separate competent shops from cosmetic ones.

Ask: how do you approach Core Web Vitals? You're looking for an answer that names specific metrics (LCP, CLS, INP), names specific techniques (image optimisation, font loading strategy, server-side rendering decisions, JS budgeting), and ideally references a target — "we aim for LCP under 2.0 seconds on a mid-range Android over 4G."

Ask: how do you handle accessibility? A weak answer is "we follow best practices." A strong answer names WCAG 2.2 AA as the baseline, mentions axe-core or similar in their QA pipeline, and can talk about colour contrast, focus management, and keyboard navigation as concrete deliverables rather than buzzwords.

Ask: what's your testing strategy? You're listening for some combination of unit tests, end-to-end tests, manual cross-device QA, and a defined regression process. "We test thoroughly" is not an answer.

Ask: what happens if a third-party API we depend on goes down at 2 AM on a Sunday? You're looking for genuine engagement with the reliability question — fallbacks, monitoring, alerting, a published response policy if they offer ongoing support.

Communication model

How they communicate during the pitch is exactly how they'll communicate during the project. If responses to your initial questions take five days, that's the rhythm. If the project lead is hard to get on a call, that's the rhythm.

Ask explicitly: what's the communication cadence? Weekly demos? Daily standups (rare and usually unnecessary for agency work)? Async updates via what tool? Slack channel? Notion workspace? Email summaries? Are clients invited into the working environment, or held outside it?

The honest answer for most projects is a weekly working session of 45–60 minutes, async updates two or three times a week through a shared tool, and direct access to the senior team via a Slack channel or similar. Agencies that wall the client off — "all communication through the project manager" — are usually managing a layer of inefficiency they don't want you to see.

Pricing model

We wrote a separate piece on fixed-price vs T&M (here), so I won't repeat the analysis. What I'll say in this guide is what the pricing model signals about the agency.

Agencies that only quote T&M for build work — without offering a fixed alternative — are usually pricing for their own risk transfer rather than the client's needs. Agencies that only quote fixed-price are usually disciplined estimators but can be inflexible mid-project. Agencies that offer both and recommend the right model for your specific project are usually the most sophisticated, because they've thought about commercial structure as a tool rather than a default.

Ask what their hourly rate is even if you're buying fixed-price. It tells you what change orders will cost.

References

Every agency will give you references. They've curated them. That doesn't make them useless — it just means you have to ask the right questions to get past the polished version.

Don't ask "were you happy with the work?" That's a softball. Ask:

• What was the hardest moment in the project, and how did the agency handle it?
• Did the final invoice match the original quote? If not, why not?
• Who actually worked on your project on a daily basis? Was it the same team throughout?
• If you were doing the project again, what would you do differently? What would you ask the agency to do differently?
• Did anything ship late? Why?
• Would you hire them again for a different project? Have you?

A reference call that produces no critical feedback at all is itself a flag. Every project has hard moments. References who can't name one are either too gracious to be useful or weren't close enough to the work to know.

Post-launch support

Ask what's included in the first 30 days after launch. The honest answer is some kind of warranty period covering bugs found in the work as delivered, usually 30 to 90 days, usually at no extra cost.

Ask what an ongoing maintenance plan looks like. If they don't offer one, that's a real flag in 2026 — a modern web stack needs continuous attention or it degrades. We wrote about why here. If they do offer one, ask what's in it: dependency updates, monitoring, monthly performance reviews, security scanning, content audits. Anything less than that is hosting, not maintenance.

A portfolio without outcomes is decoration, not evidence. Source: Pexels

🎬 Watch: The first call, the part most people skip

Process transparency shows up in the first 10 minutes — or doesn't.

Red flags that should end the conversation

There's no discovery phase in their process. They want to start building from your brief. That's not how good work gets made.

They can't explain their pricing in plain English. If the proposal has line items that don't reconcile to deliverables, or if the "investment" number drops out of a slide without any structure underneath, you're not buying a project — you're buying a black box.

They tell you they can start next week on a twelve-week project. Good agencies are booked out four to eight weeks. An agency with no backlog in 2026 either just lost a major client (which is fine but you should know) or hasn't been winning work, which is itself a signal.

Their portfolio is screenshots without results. Beautiful sites with no case study, no metric, no description of what changed for the client. That's a vanity book. You want to see "before this site, X. After, Y." If they can't measure their own work, they can't measure yours.

They badmouth a previous client to you on the first call. They'll do the same to you on someone else's first call.

Ten questions to ask in the first call

If you take nothing else from this guide, take this list.

1. Who will be on this project, week one to launch?
2. What does your discovery process produce, and how long does it take?
3. Walk me through how you'd approach our project at a high level, in five minutes.
4. What's your fixed-price vs T&M position, and why?
5. How do you handle Core Web Vitals and accessibility as part of QA?
6. What's included in your post-launch warranty, and what do ongoing plans look like?
7. Tell me about a project that didn't go to plan. What happened and how did you handle it?
8. Can you give me references from clients in years two or three of working with you, not just freshly launched ones?
9. What would make you turn down this project?
10. What's the smallest engagement you take on, and what's the largest? Where are we in that range?

The last three are the ones agencies don't expect, and the answers tell you the most.

The right agency for you might not be the most polished one in the room. Source: Pexels

How to compare quotes when they're wildly different

You'll get quotes that vary by a factor of three for what looks like the same brief. That isn't because two of the agencies are ripping you off and one is fair. It's because they're proposing materially different work, even when the surface specification looks similar.

Strip the quotes back to deliverables, hours, and team seniority. A £35,000 quote with 80 hours of senior time and 200 hours of junior time isn't the same as an £85,000 quote with 280 hours of senior time and 60 hours of junior time, even if both produce "a website." Ask each agency to break out hours by seniority. The reputable ones will. The ones that won't are usually the ones who don't want you to see the staffing model.

Look at what's missing. Does the cheaper quote include performance optimisation, or is it an add-on? Does it include accessibility QA, or "best efforts"? Does it include analytics setup, or hand-off to "your team"? Does it include a CMS configuration with editorial training, or just a generic admin panel? The gap between the quotes is usually buried in the things the low quote left out.

And look at the timeline. A 12-week timeline and a 22-week timeline for the same brief tell you different things. The shorter one is either more efficient or under-scoped. Ask which.

How Nexus answers these questions

We're a two-person senior team. We take ten engagements a year. The people on your pitch call are the people building your site, end-to-end. We have a discovery phase that produces a written SOW and an architectural plan; nothing gets quoted firm until that's done. We work fixed-scope with built-in flex post-launch. We hit Core Web Vitals as a contractual baseline. WCAG 2.2 AA is non-negotiable on anything we ship. We hold weekly demos with whoever's running it on your side, and we give you direct access to both of us via a shared Slack channel.

We don't pitch every brief. We turn down work that isn't a fit, and we'll tell you on the first call if we think you'd be better served somewhere else.

If you've worked through this guide and want to shortlist us, start with a 30-minute call. We'll talk about your project, give you an honest read on whether we're the right agency for it, and if we are, we'll send you a discovery proposal within a week.

Start the conversation.