The Real Cost of Building an App: What Agencies Do Not Tell You Upfront

A founder reached out to us last year after getting three quotes for a mobile app. They ranged from $18,000 to $95,000 for what sounded like the same scope. All three agencies told her a different story about why theirs was the right number.

None of them explained what was actually in the price.

That is the problem with how most agencies quote software. The number looks concrete, but it is built on assumptions nobody spells out. This post explains what those assumptions usually are, so you can ask the right questions before you sign anything.

The Quote Only Covers One Phase

When an agency says "we'll build your app for $40,000," they almost always mean the initial build only. Design, development, testing for one platform, one set of features, one round of revisions.

What they are not quoting: ongoing hosting, third-party API costs, post-launch bug fixes, the second platform (if you start on iOS, Android comes later), any new features, or the time it takes to onboard your team and actually use the thing.

A $40,000 build can easily cost $80,000 over 12 months once you add those layers. Not because anyone was dishonest, but because "build cost" and "total cost of ownership" are two different numbers, and most agencies only give you one.

Design Is a Full Discipline, Not a Line Item

Good design takes time. A well-designed app for a real product involves user research, wireframes, multiple rounds of mockups, a design system, and handoff specs for developers. That is easily 80 to 150 hours of work depending on scope.

Some agencies include design. Some quote it separately. Some hand you a Figma template and call it done.

If your quote says something like "UI/UX: included" with no hours attached, ask how many hours are actually scoped. The answer tells you a lot about whether you are getting a real design process or a checkbox on a proposal.

Third-Party Services Add Up Faster Than You Think

Most modern apps depend on third-party services: authentication, push notifications, maps, payments, email, SMS, AI models, and so on. These are not free, and they are not included in your dev quote.

Twilio SMS can run $0.0079 per message. Fine at 100 messages a month. A different story at 50,000. Stripe charges 2.9% plus 30 cents per transaction. An AI API call for a features can cost $0.01 to $0.10 depending on the model and the prompt length.

These costs are hard to predict without understanding your actual usage patterns, but you should at least ask your agency to walk through every external dependency and give you a rough monthly estimate at your expected scale. Most will not do this unless you ask directly.

Platforms Are Not Interchangeable

"We need both iOS and Android" is often treated as a single bullet point in a scope document. In practice, it can mean 40 to 60% more development time.

React Native and Flutter help close the gap, but they do not eliminate it. Each platform has its own design conventions, review process, update cycle, and edge cases. A developer who is strong on iOS may be slower on Android, and vice versa.

If you are early stage, pick one platform. Ship it. Learn from real users. Add the second platform when you have validation and budget. This is the boring advice that saves companies tens of thousands of dollars.

Revisions Are Where Projects Get Expensive

Most project quotes include a round or two of revisions. What that actually means varies enormously.

One agency's "unlimited revisions" means feedback within the agreed scope. Another's "two rounds" means any change after the second review is a change order. Neither is wrong, but they produce very different project economics.

The cleaner thing to do: agree upfront on what counts as in-scope vs. a change order, and get that in writing. The agencies that resist this conversation are the ones you should be most careful with.

Post-Launch Support Is Real Work

Launching is not the end. After launch, you will have bugs. Some will show up in the first 48 hours once real users hit the app. Some will take weeks to surface. There will be app store updates that break something. There will be a dependency that goes out of maintenance.

Agencies handle this in a few different ways: a fixed retainer, a block of pre-paid hours, or ad-hoc billing. Some include 30 or 60 days of post-launch support in the initial contract. Many do not.

Ask what happens the first time something breaks after launch. The answer should not be a vague "we'll take care of it." It should be a clear process with a clear cost.

What Honest Pricing Actually Looks Like

A good agency should be able to give you two numbers: what the build costs, and what the total cost of ownership looks like over the first year. The second number includes hosting, third-party services, expected support hours, and a buffer for the things you will inevitably want to add.

It will be a higher number. That is fine. It is the real number, and making a decision with the real number is better than being surprised six months in.

At SimplyShip, we do not hide the second number. We think it is more respectful to your budget and more honest about what we are actually getting into together. If you are evaluating your options for a new project, we are happy to walk through what the full picture looks like for your specific case. No sales pitch, just the numbers.