Choosing a Shopify Plus agency is a bigger decision than most brands treat it as. You're not buying a website. You're picking the team that will own your commerce infrastructure for the next few years, whether you renew with them or not.
Every agency site looks the same. Clean portfolio, client logos, a few case studies with impressive-sounding stats. That tells you almost nothing about whether they'll be good to work with. Here's what actually matters, and how to check it before you sign anything.
Shopify Plus experience, specifically
A lot of "Shopify experts" have built five stores on standard Shopify and none on Shopify Plus. Plus has its own complexity: checkout extensibility, B2B, multi-market, higher API limits, and the operational weight of running a store doing real volume. Ask how many Plus builds they've shipped, not Shopify builds in general. Ask to see two or three of them live, not just in a case study screenshot.
How they price
Open-ended hourly billing is a red flag for a build of any real scope. You want a fixed-price Phase 1 that scopes the actual build, with a clear roadmap for what comes after. If an agency can't give you a number until they've billed 40 hours of discovery, that's not confidence, that's a lack of process. Ask what's included in Phase 1, what triggers a change order, and how they handle scope that grows mid-build. Every serious agency has a clear answer to that last one because it happens on almost every project.
What happens after launch
This is the question most brands forget to ask. Sites need ongoing work: bug fixes, new features, integration maintenance, performance tuning. Ask what the retainer looks like, how fast they turn things around, and whether the same team that built it sticks around to support it. A lot of agencies hand off to a junior support team the day after launch, and response times quietly stretch from hours to weeks.
Who's actually doing the work
The person in your sales call is rarely the person writing your code. Ask directly who will be on the build, what their experience looks like, and whether you'll have access to them during the project. If the answer is vague, that's your answer. Bigger agencies especially tend to staff the pitch with seniors and the delivery with whoever's free. Ask for names, not job titles.
How they handle communication
Ask what a normal week looks like. Weekly calls? Async Loom updates? A shared Slack channel? Mismatched communication styles cause more agency relationships to sour than bad code does. If you need frequent check-ins and they run lean async updates, that friction will show up fast. Match the cadence to how you actually work, not how it sounds in a pitch.
Red flags worth walking away from
- Can't name specific Shopify Plus projects when asked directly
- Won't commit to a fixed price without weeks of paid discovery first
- Vague about who's actually doing the engineering
- No clear answer on post-launch support or response times
- Pushes you toward the most expensive option before understanding your actual problem
Talk to actual clients
Case studies are marketing. A 15-minute call with a past client tells you more than any portfolio page. Ask about communication, whether timelines held, how they handled scope changes, and what they'd do differently if they started again. If an agency hesitates to connect you with a reference, that hesitation is information too.
The agencies worth hiring won't flinch at any of these questions. The ones that dodge them are telling you something too.
Still deciding whether an agency is the right call at all? See our breakdown of Shopify Plus agency vs in-house team for the fuller cost and control trade-offs.
How much does a Shopify Plus agency cost?
Custom builds typically run from $40K to $150K+ depending on scope. Theme-based builds with integrations sit at the lower end. Headless architecture with custom backend logic and complex integrations sits higher.
Should I choose an agency with a big team or a smaller specialist shop?
Depends on your needs. Bigger agencies offer more bench strength for large, complex builds. Smaller specialist shops often give you more senior attention and faster decisions. Neither is automatically better, ask who's actually on your project either way.
How long does a Shopify Plus agency engagement typically last?
Most builds run 10 to 20 weeks. Many brands then move to an ongoing retainer for continued development and support after launch.
What questions should I ask in the first sales call?
Ask how many Shopify Plus builds they've shipped, who specifically will work on your project, how pricing works, and what post-launch support looks like. Vague answers to any of these are worth probing further before you commit.
Should I get quotes from multiple agencies?
Yes. Two or three quotes gives you a sense of realistic pricing and lets you compare how each agency scopes the same problem. Wildly different quotes usually mean wildly different assumptions about scope, worth clarifying before you decide.
What's a reasonable response time for post-launch support?
For anything urgent, same-day acknowledgement is reasonable. For non-urgent requests, a few business days is normal. If an agency can't tell you their typical turnaround, that's worth asking about directly before signing.
Can a Shopify Plus agency work with our existing developers?
Most good agencies can, especially for larger builds where an in-house team handles day-to-day changes and the agency handles major projects. Ask how they'd structure the handoff and documentation if this is your plan.
How do I know if an agency actually built what's in their case studies?
Ask for the live site and check it yourself. Ask specific questions about the build (what platform, what integrations, what the biggest challenge was) and see how detailed and confident the answers are.
Flux is a Shopify Plus Agency for AI Search, Design & Engineering
- Check for Shopify Plus specific experience, not general web dev
- Ask how pricing works: fixed-price phases beat open-ended hourly
- Look at what happens after launch, not just the build
- Ask who's actually doing the work, not who's in the pitch
- Reference calls matter more than case study PDFs
