Mobile App Development Company
Who builds your mobile app and keeps it alive after launch?
ETREXIO is a software studio based in the United States and Türkiye that designs, builds and operates iOS and Android apps together with the backends behind them. Two senior builders lead a human-in-the-loop AI workforce, supported by our in-house products DigiSapiens and StackWatch. We have shipped 50+ products, hold a 4.7 rating on Clutch, and our average client stays 5 years. Retainers start at $5,000 per month and cover design, development, deployment and 24/7 operation.
The mobile app market punishes neglect. An app that ships and then sits still starts dying the day iOS updates, a new device family launches, or a store policy changes. Most agencies price the build and treat everything after launch as someone else's problem. We price the lifecycle: the same retainer that ships your app keeps it reviewed, updated, monitored and improving for years.
We have shipped consumer apps with 100,000+ users, two-sided apps where a parent and a driver see different products, and app-plus-backend systems where the app is only the visible tip. The common thread is that we never build the app alone. APIs, admin panels, notifications and payments ship alongside it, because an app without its system is a screenshot, not a product.
Post-launch is where our in-house products earn their keep. StackWatch watches crashes, API errors and performance around the clock; when Dr. Moku's language apps needed their crash rates cut, that monitoring loop did the work, and the improved stability lifted their store rankings. Apps are ranked by how they behave in the wild, and we are the team still watching when yours misbehaves at 3 a.m.
What we build
An app is a system, not a screen.
iOS and Android from one codebase.
Cross-platform apps that feel native, shipped to the App Store and Google Play, going native where performance genuinely demands it.
The app is the tip of the system.
APIs, admin panels, notifications, payments and analytics built alongside the app, so you launch a product, not just a client.
Store releases without drama.
Review submissions, staged rollouts, crash monitoring and hotfixes handled by us, on a release cadence your users can trust.
Alive long after launch day.
StackWatch watches crashes, API errors and performance 24/7. OS updates, new devices and store policy changes are our problem, not yours.
How we approach it
How we take an app from idea to the stores, and keep it there.
The build is the first 90 days. The product is the years after. Our process covers both.
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Scope to a shippable core.
We cut the first version to the loop users repeat daily and defer everything else. Kidu's parent app, driver app and admin shipped in 3 to 4 months because scope was ruthless, not because corners were cut.
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Design for the actual user, including the five-year-old.
Interfaces are shaped by who really uses them. For Kidu that meant a child-friendly emoji UI; for Dr. Moku it meant learning flows that work offline on a plane or a subway.
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Build the backend as a first-class citizen.
APIs, admin panels, push infrastructure and payment flows are built with the app, so the day the app ships, the business behind it works too.
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Release through the stores without drama.
Review submissions, staged rollouts and rollback plans are our responsibility. Store rejections get resolved by people who have shipped 50+ products through review.
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Operate, measure, improve.
Crashes, API errors and performance stream into StackWatch 24/7. Fixes and features flow through the same monthly retainer, which is how client apps keep climbing rankings years after launch.
Real work
Apps we built and still operate.
Consumer scale, safety-critical logistics and a funded gaming product, all named and verifiable.
Language apps with 100,000+ users, five years and counting.
Bob Byrne's Dr. Moku teaches Japanese, Korean, Chinese and Arabic to 100,000+ users. We built the offline learning feature that lifted sales 36 percent, and StackWatch-driven fixes cut crash rates and lifted store rankings. Dr. Moku has been a client for 5 years, which is the real review of an app operations partner.
Safe rides for kids, three apps, one small team.
Kidu, a Sabancı intrapreneurship venture led by Sevim Örs, needed safe school rides parents could trust. We shipped the parent app, driver app and admin in 3 to 4 months with a 2-person client team: route deviation alerts for parents, a child-friendly emoji UI for kids. Kidu went on to receive a $150k investment from Sabancı.
Shipped fast enough to save the company.
Fundle came to us with months of runway after an in-house build had failed. We shipped their game library app fast enough to matter, and in 2024 Fundle raised at a $5M valuation. CEO Alican Karaman's math: without us he would have needed 6+ hires overnight.
The offline feature alone lifted our sales by 36 percent. ETREXIO built it, shipped it, and kept the apps stable enough that our store rankings went up.
Questions
What founders ask about mobile apps.
How much does mobile app development cost with ETREXIO?
Monthly retainers from $5,000, covering design, development, deployment and 24/7 operation of both the app and its backend. No separate maintenance contract.
Native or cross-platform: which do you recommend?
Cross-platform for most products, because one codebase ships faster and costs less to operate. We go native for the specific screens or features where it truly pays.
Do you keep updating the app after launch?
Yes, that is the point of the retainer. OS updates, store policy changes, crash fixes and new features all flow through the same monthly engagement. Dr. Moku has been running this way with us for 5 years.
Can you take over an app another team built?
Yes. We audit the code and the store accounts, stabilize the riskiest parts, put it under StackWatch monitoring, and continue development from there. Fundle came to us exactly this way, after an in-house build failed with months of runway left.
How long does it take to get an app into the stores?
A focused first version typically reaches the stores in 8 to 14 weeks, including backend and review cycles. Kidu's parent app, driver app and admin shipped in 3 to 4 months as a set.
Do you build the backend and admin panel too?
Always. APIs, admin panels, notifications, payments and analytics ship with the app. For Kidu that meant a parent app, a driver app and an admin working as one system from day one.
Can you build apps for children or safety-critical use?
Yes. Kidu is safe transportation for kids: route deviation alerts for parents, a child-friendly emoji UI, and driver-side tooling built around accountability. Safety and privacy constraints are design inputs, not afterthoughts.
How do you improve an app's store ranking?
Stability first: store algorithms punish crashes and ANRs. StackWatch monitoring plus fast fix cycles cut Dr. Moku's crash rates, and their rankings rose as a result. We pair that with store listing and review-prompt optimization.
What if we only have a small team on our side?
That is our normal client. Kidu shipped three apps with a 2-person team on their side, and Fundle avoided 6+ overnight hires. We bring the engineering organization; you bring the product decisions.
Do you handle offline functionality and sync?
Yes, and it is often underrated: the offline learning feature we built for Dr. Moku lifted sales 36 percent. Local-first storage, conflict-safe sync and graceful degradation are standard tools in our builds.
Client perks
Clients unlock up to $250,000 in tool perks.
Client perks include
Perk availability depends on provider eligibility at the time of engagement.
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