What a $5M-$100M+ ecommerce brand should expect from a Shopify Plus agency

The expectation gap

Most brands hire a Shopify Plus agency hoping for a partnership and end up with a vendor relationship. The disappointment usually shows up around month three: the agency is delivering what was scoped, but the strategic input you expected isn't materialising. The PM is responsive but reactive. Nobody's pushing back on bad ideas. Nobody's surfacing opportunities. You're getting hours of work for your money, not outcomes.

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This is the most common pattern we see when brands move between agencies. They were paying for delivery and assumed strategy was included. It usually isn't.

What you should actually expect

Strategic discovery, not just requirements gathering

A good Shopify Plus agency starts with discovery, not design. That means asking the questions you haven't asked yourself: where's your conversion bottleneck, what's your real customer LTV, which pages drive the most revenue, what's your roadmap looking like 18 months out? Before they touch a wireframe, they should have a clear picture of what success actually looks like for your business.

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Watch for agencies that skip this and go straight to scoping. They're treating you like a website project, not a commerce business. Read our piece on hidden migration costs. If an agency wants to skip discovery and start designing, they're either confident they'll find issues mid-build (and bill for them) or they don't realise what they're missing.

A specific point of view on architecture

You're at $5M-$100M+. Your store needs to be making explicit architectural decisions: classic Shopify Plus or headless? Native search or Algolia? Native CMS or Sanity? Native subscriptions or Recharge?

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An agency at your scale should have a clear default stack and clear reasons for it. Not because every brand needs the same stack, but because if they don't have one, they're not making informed recommendations: they're recommending whatever the last project used.

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At Flux, our default stack is Hydrogen, Sanity, and Algolia. We can articulate exactly why and exactly when we'd recommend something different. That's the level of clarity you should expect from any agency you're considering.

People who'll push back

The agency you want is one that will tell you when you're wrong. When your scope is bloated, when your timeline is unrealistic, when your design direction is going to hurt conversion, when the third-party app you've fallen in love with is going to create technical debt.

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Pushback is a sign of investment in outcomes. Agencies that say yes to everything are usually optimising for short-term revenue, not your long-term success. The conversations that feel uncomfortable in week three are the ones that prevent disasters in week thirty.

Ongoing performance accountability

The launch isn't the goal. The goal is sustained business growth on the platform. A good agency stays accountable for outcomes after launch: tracking conversion rate trends, flagging performance regressions, surfacing optimisation opportunities, and ensuring the technology investment continues to pay back.

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This is where the difference between a project shop and a strategic partner becomes obvious. Project shops disappear after launch. Strategic partners stay engaged because the relationship is the asset, not the project.

Pricing reality

Initial builds

For a brand at $5M-$100M+ scale, expect a Shopify Plus build to cost $80K-$300K depending on complexity. The variables that move it: catalogue size, integration count, design complexity, custom functionality requirements, and whether you're going classic Plus or headless.

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Headless adds 50-100% to the build cost compared to classic Plus, but for many brands at this scale, the performance and flexibility gains justify it. We covered the trade-offs in detail in the real cost of going headless.

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Platform migrations from Magento, WooCommerce, or BigCommerce add 20-30% to any of these ranges. Data migration, redirect mapping, and integration rebuilds all carry overhead that fresh builds don't have.

Ongoing retainers

Post-launch retainers typically run $5,000-$25,000 per month depending on what's included. At the lower end, you're getting bug fixes and minor feature work. At the higher end, you're getting strategic optimisation, continuous improvement, performance monitoring, and proactive opportunity identification.

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The retainer rate is less important than what's covered. A $25K retainer that includes strategy, design, dev, and analytics is often better value than a $10K retainer that's pure dev hours.

What to be sceptical of

If an agency quotes a fixed price for a $5M+ brand without doing real discovery, walk away. They've either underscoped (you'll get hit with change orders) or they're going to deliver to spec, not to outcomes.

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If they can't articulate a specific architectural recommendation in your first meeting, walk away. They're not bringing experience: they're bringing capacity.

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If their pricing is dramatically below the ranges above, ask why. Either they're inexperienced (and you'll pay for the learning curve), based offshore in ways that may create timezone or quality issues, or they're underpricing to win the deal and will scope-pad to make it profitable.

Questions to ask in the pitch

The questions that separate strategic agencies from delivery shops:

• What's your default Shopify Plus tech stack and why?
• What's your last failed project and what did you learn?
• How do you decide when to recommend headless vs classic Plus?
• What's your typical post-launch performance trajectory for a brand at our scale?
• Who specifically will be working on our project? What's their experience level?
• What's your retainer structure, and what's actually covered?
• How do you handle scope creep mid-project?
• What's the worst part of working with you? (Yes, ask this directly. The answer tells you a lot.)

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The quality of the answers matters more than the questions. Vague answers, defensive answers, or rehearsed sales answers all suggest you're talking to a sales-led organisation. Specific, honest, sometimes self-critical answers suggest you're talking to people who actually do the work.

The relationship structure that works

The strongest Shopify Plus agency relationships at the $5M-$100M+ scale typically follow this structure:

Discovery first, then build

A paid 2-4 week discovery phase before any build commitment. This is where strategic alignment happens, where the architecture decisions get made, and where the real scope reveals itself. It's also where you find out whether you actually like working with the agency.

Fixed-scope core build

The core build is fixed-scope. Everyone knows what's being delivered, when, and for how much. Change orders happen, but they're explicit and documented, not hidden in an hourly model.

Retainer for ongoing work

Post-launch, the relationship moves to a retainer that covers continuous optimisation, new feature development, and strategic input. Hours roll forward, not back. There's a clear quarterly review on outcomes, not just hours used.

Annual strategic review

Once a year, the agency steps back and assesses the platform, the architecture, and the roadmap with you. Not selling new work, not renewing the retainer, just looking at where you are and where you should be heading. This is the input that prevents the slow drift that kills most agency relationships.

The bottom line

At your scale, the cost of choosing the wrong agency isn't the project fee. It's the 18 months of suboptimal decisions, the conversion rate that should have been 0.5% higher, the technical debt that compounds with every release, the strategic opportunities you didn't see because nobody was paying attention.

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The right agency is one that treats your store like the revenue infrastructure it is, brings strategic thinking to every conversation, and stays accountable for outcomes long after launch. That's the standard. If you want to know what that looks like in practice, talk to us.