Most founders pick a web development company the same way they pick a restaurant on a road trip: whoever has the best pictures and the closest exit. That works for lunch. It does not work for a $50,000 to $500,000 build that your business depends on for the next three years.
The good agencies and the bad ones look identical from the outside. Same testimonials, same case studies, same "trusted by" logo wall. The difference shows up in how they answer specific operational questions before money changes hands. Below is the exact 12-point checklist we'd run an agency through if we were the buyer, with the answers that should make you confident, and the ones that should make you walk away.
If you're earlier in the process and still deciding between an agency, freelancers, and an in-house team, read our breakdown on when to hire an agency vs build in-house first. The guide below assumes you've already decided an agency is the right fit.
1. Who, exactly, will write the code?
Sales pitches show you the senior leadership. Builds get done by whoever the agency assigns. There's a multiplier effect of 5 to 10x in productivity between a senior engineer and a recently-hired junior. Get specific names, ask for their LinkedIn, and ask whether they're full-time staff or contractors brought in for your project.
Good answer: "Here are the three engineers we'd put on this. Two are full-time, one is a long-term contractor we've worked with for two years." Plus links.
Red flag: "We have a team of 50+ developers." That's a sentence designed to avoid the question.
2. What does your build process look like, week by week?
You're not asking for a Gantt chart. You're asking whether they have one. A real agency will describe their cadence: discovery doc → design sprint → 2-week build sprints → demo every Friday → bug-fixing buffer → handoff. A bad agency will say "we're flexible," which translates to "we figure it out as we go."
3. How many demos will I see, and when?
This is the single most predictive question for whether a project will go off the rails. Founders who see working software every 1 to 2 weeks catch scope drift early. Founders who see "almost ready" PowerPoints for three months end up with a product that doesn't fit their business. Demand bi-weekly demos, in writing, in the contract.
4. What happens if I want to change something mid-build?
Two patterns. (a) "We have a change-request process. Small changes are absorbed; bigger ones get re-quoted before we touch them." (b) "We just charge by the hour, so anything is fine." The second sounds friendly and is actually how budgets explode. Pattern (a) protects both sides.
5. Show me your last three projects' Lighthouse scores
This is a quick technical-quality litmus test. A competent web development agency in 2026 should ship Lighthouse Performance scores in the 85 to 100 range on real-world pages, not just the marketing homepage. If they can't show you, or the numbers are in the 40s and 50s, performance is not part of how they think. That'll bite you on Core Web Vitals and SEO from launch day. We covered why that matters in our technical SEO checklist for SaaS sites.
6. Who owns the code and assets when we're done?
The contract should say "client owns all source code, design files, and credentials at project completion, including for any abandoned features." If the agency hesitates here or wants to retain "exclusive rights," walk. You can never effectively migrate to another vendor if you don't actually own what was built.
7. What's the post-launch support model?
Most projects need 5 to 15% of build cost annually for maintenance, bug fixes, dependency upgrades, small feature requests. Ask: do they offer a support retainer? At what hourly rate? With what SLA on response time? An agency without a clear post-launch model is signaling they want the upfront money and don't want to think about you again.
8. Can I talk to one current and one past client?
Not a curated reference list. Specifically: their oldest active client, and one client whose project was completed 12+ months ago. Past clients are the truth tellers, they're past the contract, no longer dependent on the relationship, and will tell you whether the work held up.
9. What's your hiring/QA process?
You're trying to surface whether they have one. The answer should mention: technical interviews, paired-programming tests, code review on every PR, automated testing in the deploy pipeline. If the answer is "we hire who we trust," that means there's no consistent quality bar.
10. Show me the staging environment for a current build
Polished case studies on a portfolio site are PR. A live staging URL of work in progress is reality. The good agencies are happy to show this (with NDA where appropriate). The agencies that hide everything until launch are usually hiding something.
11. What's not included in this quote?
Get an explicit list. Common surprises: third-party API costs (Twilio, Stripe, SendGrid), hosting and CDN, SSL certs and domains, app store fees, design system creation if not in scope, content writing and image sourcing, post-launch training. A good agency volunteers these. A bad one lets you discover them via invoices.
12. What size of project do you NOT want to take on?
This is a trap question, on purpose. Every honest agency has a sweet spot. We typically don't take on six-month enterprise rebuilds where we can't pick the team or the stack. An agency that says "we love every project of every size" is either lying or struggling for work.
The two-page test
Beyond the questions, there's a simpler tell. After the discovery call, ask the agency to send you a short two-page summary of their understanding of your project. Treat it like a job interview write-up. The good agencies send something specific to your business. The mediocre ones send a recycled template with your name dropped in.
You can run this whole 12-point check in two calls and a 30-minute review of the deliverables. It is the cheapest insurance you'll ever buy on a software build.
What we'd do at DevEntia
If you're evaluating web and software development agencies for a 2026 build, we're happy to be one of the names on the spreadsheet. We answer all 12 questions above directly, on the first call, in writing where it matters. Drop us a brief here and we'll send you the two-page summary within 48 hours, no strings.