If you’ve ever Googled this question, you’ve probably been met with a frustratingly vague answer: “it depends.” And while that’s technically true, it’s not particularly helpful when you’re trying to plan a budget, pitch an idea to stakeholders, or figure out whether your launch date is even realistic.
So let’s do better than “it depends.”
After 12 years building mobile apps for clients across a range of industries, here’s what we’ve actually learned about timelines — the honest version, not the sales pitch.
The First Question We Always Ask
When a new client gets in touch, one of the first things we ask is: “Do you have a fully formed plan, or do you need us to help you design and lay out the app?”
Most clients assume they’re arriving with a clear brief. In reality, the discovery and planning phase — the part where we figure out exactly what the app needs to do, how it should work, and how it connects to any existing systems — is often invisible to them before they arrive. They have an idea. Sometimes a great one. But an idea is not a specification.
This matters for timelines because design and planning isn’t a footnote — it’s one of the most time-consuming phases of the entire project. Getting it wrong, or rushing it, is one of the surest ways to blow your delivery date later.
The Simple Answer: Three Tiers of Complexity
Before we get into the nuance, here’s a rough rule of thumb based on real projects:
| App Complexity | Typical Timeline |
|---|---|
| Simple (on-device, no server) | ~3 months |
| Medium (some third-party integration) | 3 months – 6 months |
| Complex (server-side, multiple integrations, large feature set) | 6 months – 1 year+ |
These are not estimates pulled from thin air. They’re based on what we’ve actually seen. But as you’ll read below, these numbers assume everything goes smoothly — and something almost always doesn’t.
The Single Biggest Variable: Does Your App Talk to the Outside World?
One of the most underappreciated factors in app development timelines is whether your app operates entirely on the device, or whether it needs to communicate with a server or third-party services.
On-device apps — those that work purely with data stored locally on the phone — can move relatively quickly. There’s no API to integrate, no server to configure, no authentication flow to build. A good example from our own work is a comedy golf scorecard app we developed. It was a self-contained experience: all the logic lived on the device, no external services were involved, and we delivered it in around 3–4 months. For a medium complexity app, that’s a solid turnaround.
Apps that call out to third-party services or a backend server are a different beast entirely. Every integration point is a potential delay — whether that’s waiting on API documentation, dealing with authentication edge cases, or debugging issues that only appear in production. Add several of these together and you can easily double your timeline.
The Four Phases of an App Project
Our process breaks down into four stages, and each one contributes to the overall timeline in ways clients don’t always anticipate:
1. Free Project Review We start with a no-obligation conversation to understand your content, your systems, and what you need the app to do. This isn’t just pleasantries — it’s where we establish whether the project is feasible and what shape it actually needs to take.
2. Proposal & Plan You receive a clear, detailed proposal with timeline, investment, and exactly how your app will connect to what you already have. This is the stage where we catch the assumptions that would otherwise derail the build later.
3. Build & Launch We develop, test, and refine — then take it through the App Store and Google Play submission process. Note that “submission” is not the finish line. It’s a process in itself (more on that below).
4. Grow & Evolve Your app is not a one-off project. We stay connected, support new features, and help you scale as your audience grows. This phase is often completely absent from other timeline discussions — but the reality is that a good app evolves over time, and that takes ongoing time and resource.
App Store Submission: The Delay Nobody Plans For
Here’s a phase that almost every client forgets to factor into their launch timeline: app store review.
Google Play is generally relatively quick. The review process is straightforward, mainly automated and you can usually expect your app to go live without too much friction.
Apple is a different story. The App Store is significantly stricter, with a longer list of conditions & requirements and a mostly manual review process. It’s not unusual to go through multiple rounds of review and revision before Apple approves your submission. If your app has any complexity — in-app purchases, third-party logins, certain permissions — expect this to take longer than you think.
The lesson: don’t schedule your launch event for the same week you plan to submit to the App Store.
The Factor That’s Entirely Within Your Control (But Often Isn’t)
Here’s something we’ve learned that no technical article will tell you: the client is often the biggest variable in the timeline.
Slow feedback. Assets that arrive weeks late. Decisions that get revisited after the build has moved on. These things can grind a project to a halt just as effectively as any technical problem — sometimes more so.
If your developer sends you a set of screens to review and you sit on them for three weeks, that’s three weeks added to your timeline. It sounds obvious when stated plainly, but in the middle of a busy working life, it’s easy to let these things slip.
The best clients we’ve worked with are the ones who treat the project like a collaboration — responsive, decisive, and engaged. They get the fastest builds.
Don’t Forget Beta Testing
Another thing that gets compressed or forgotten when clients are chasing a deadline: beta testing.
Real-world testing — with actual users on actual devices — is not optional. It’s where you discover the things that didn’t surface in development: edge cases, performance issues, UX confusion, device-specific bugs. This phase needs to be built into your timeline, not bolted on at the end when everyone is under pressure.
We’ve seen projects where a client pushed hard to hit a trade show deadline, only to scramble through beta testing in the final two weeks and launch with issues that could have been caught earlier. The deadline was technically met. The launch wasn’t the success it should have been.
The Single Best Thing You Can Do to Keep Your Timeline on Track
If there’s one piece of advice we’d give to every client before a project begins, it’s this:
Define your minimum viable product — and stick to it.
An MVP is the smallest version of your app that still delivers genuine value to users. It’s not a compromise or a lesser version. It’s a discipline. It forces you to prioritise ruthlessly and resist the temptation to add features mid-build.
Scope creep is one of the most common reasons projects overrun. A client starts with a clear brief, then halfway through the build has an idea for “just one more feature.” Then another. Each addition, however small it seems, adds time — sometimes significantly, because it can require rethinking things that were already built.
The good news: you can always add to your app in future releases. Version 1.0 doesn’t have to do everything. Get the core product into users’ hands, see what they actually respond to, and iterate from there.
One Last Thing — And This One Might Sting
Before you start planning timelines and budgets, here’s the question we’d encourage every new client to sit with:
Have you checked if your app already exists?
The App Store and Google Play are crowded places. If something very similar to your idea is already out there, you need to ask yourself: are you willing to compete with it? Do you have a meaningful unique selling point?
If there’s competition, that’s not necessarily a dealbreaker — but it changes what you need to build and how you position it. There may be many apps that do the same thing, but does your idea do it better?
And if there’s no competition at all? If you’ve genuinely found a gap in the market?
Do it now!
