Mobile App Development Company: Custom App Creation Services

Updated September 2026 · Written and maintained by the Progression Agency strategy team

Progression Agency is a New York City app development company building iOS, Android and cross-platform apps for businesses across the United States. We plan, design, build, launch and maintain mobile apps and the backends behind them — and because we are also a marketing agency, we build the launch plan that gets an app installed alongside the app itself. This page explains what our mobile app development services cover, how a project runs from first call to store release, what drives cost and timeline, and how to compare any app development company you are considering.

What does an app development company do?

An app development company designs, engineers, tests, publishes and maintains mobile applications for iPhone, iPad and Android devices, usually together with the backend services and admin tools that make the app work. A full-service firm also handles discovery before the build and store optimization and user acquisition after it.

In practice that means a cross-functional team: a product lead who turns business goals into a feature list, UX and interface designers, mobile engineers for iOS and Android or a cross-platform framework, backend engineers for accounts, data and integrations, and QA specialists who test on real devices. Progression Agency puts all of those roles under one engagement so you have a single accountable partner rather than a chain of freelancers.

Our mobile app development services

Native iOS app development

We build iPhone and iPad apps in Swift and SwiftUI following Apple’s Human Interface Guidelines, so the app feels at home on the platform and passes App Store review cleanly. Native iOS is the right call when an app depends on deep hardware access — camera pipelines, HealthKit, Apple Pay, widgets, Live Activities — or when your audience is overwhelmingly on iPhone, which is common for US consumer products.

Native Android app development

Our Android work uses Kotlin and Jetpack Compose and is tested across the range of screen sizes and manufacturers Android users actually carry. Android matters most for field and logistics apps running on rugged devices, for products aimed at international markets, and for any business whose customer base skews toward Android.

Cross-platform app development

For most business apps we recommend a cross-platform build in React Native or Flutter: one codebase, both stores, near-native performance and a materially lower cost to build and maintain. Our detailed comparison of the two frameworks lives on the cross-platform app development page.

Backend, API and admin development

The backend is frequently the larger half of an app: user accounts and authentication, databases, file storage, payments, notifications, third-party integrations and the admin panel your team uses to run things. We scope it as its own line item so it is never a surprise, and we build it on managed cloud infrastructure that scales with usage.

AI features inside your app

Assistants, natural-language search, document and image understanding, recommendations and automated support are now practical to build into business apps. Our AI app development service covers model selection, retrieval over your own data, cost control and the guardrails that keep answers on-brand.

App UX and UI design

Design is where adoption is won. We map the flows users will actually take, design the interface to each platform’s conventions and hand you a clickable prototype to put in front of real users before a line of production code is written.

App maintenance and support

Apple and Google ship major operating-system releases every year and periodically raise the minimum build targets the stores accept, so every live app needs ongoing care even if its features never change. Our maintenance plans cover OS compatibility, dependency and security updates, crash monitoring, bug fixes with agreed response times and small feature work.

App launch, store optimization and marketing

This is the service that separates us from a pure development shop. We set up analytics and attribution before launch, write and test store listings for App Store and Google Play search, and run the paid social and search campaigns that drive installs. See our mobile app PR and performance marketing services for the growth side.

Native vs cross-platform: which should you build?

Choose cross-platform for most business, commerce and content apps because one codebase reaches both stores faster and for less. Choose native when the app’s core value depends on platform-specific hardware, graphics performance or features that cross-platform frameworks reach only through extra native modules.

How our app development process works

Seven stages: discovery, scope and estimate, UX and interface design, sprint development, QA, store submission and launch-and-growth. Each sprint ends with a build you can install on your own phone, so progress is visible every two weeks.

Discovery: deciding what the first release must do

We start by identifying the single job the app must do exceptionally well for its first users, then the minimum set of features that job needs. Everything else goes on a roadmap. A tightly defined first release reaches the stores sooner, costs less and gives you real usage data to decide what comes next.

Sprints you can hold in your hand

Development runs in two-week sprints. At the end of each one you receive an installable build through TestFlight or a Google Play test track, plus a short written summary of what shipped and what is next. Direction changes are cheap when they happen early, and this rhythm makes sure they do.

Store submission without the surprises

Both stores review apps before publication. We prepare privacy disclosures, screenshots, review notes and test accounts in advance, and we handle any reviewer feedback. New personal Google Play developer accounts must now run a closed test with at least 12 testers opted in for 14 continuous days before production release, and we plan that window into the schedule.

How long does it take to build an app?

A focused first release commonly takes three to four months; a moderately complex two-platform business app with a custom backend commonly takes five to seven months; enterprise apps with many integrations or regulated data can run longer. Scope, integrations and approval cycles drive the schedule far more than raw coding time.

How much does app development cost?

As a planning range, a focused first release commonly lands between roughly $40,000 and $100,000, a full-featured two-platform business app between roughly $100,000 and $250,000, and complex marketplace or enterprise apps above that. Ongoing maintenance is commonly budgeted at around 15-20% of the build cost per year.

The biggest cost drivers are the number of platforms, the size of the backend, third-party integrations, the number of distinct user types, and whether the app handles regulated data. Store fees are small by comparison: the Apple Developer Program costs $99 per year and a Google Play developer account carries a one-time $25 registration fee. For the full breakdown, see how much it costs to build an app.

Why choose Progression Agency as your app development company?

• One team from idea to installs. Strategy, design, engineering, launch and marketing under one engagement.
• You own everything. Source code, repositories, developer accounts and signing credentials sit in your name from day one.
• Fixed, written scope. A named first-release feature list and estimate before development begins.
• Visible progress. An installable build every two weeks, with a written summary.
• Launch built in. Analytics, store optimization and acquisition planned before release, not after.
• New York based, nationwide. Headquartered in New York City and working with clients across all 50 states.

How to choose an app development company

Compare firms on ownership terms, how they scope the first release, how they handle the backend, what maintenance covers, how often you see working builds, and whether they have a plan for getting the app installed. Portfolios matter, but these six answers predict how the project will actually go.

App development in New York and across the US

Progression Agency is headquartered in New York City, and we meet NYC clients in person for discovery and design workshops. Most of our app clients are elsewhere in the United States, and the process runs just as well remotely. If you are specifically looking for a local partner, see our app development company NYC page.

Related software development services

Apps rarely live alone. Many of our app projects sit alongside custom software development, web application development, website design and development and AI automation. We plan them together so the data, accounts and branding line up across every surface your customers touch.

Apps we build for every industry

The table lists the app we are most often asked to build in each industry we serve. For the wider software picture in each industry see custom software development.

Mobile app creation services for companies

Progression Agency provides end-to-end mobile app creation services for companies: strategy, design, iOS and Android development, backend, launch and maintenance under one contract. App development for companies differs from consumer app work because it has to fit existing systems, brand standards, security reviews and internal approval chains.

As a US mobile app development company we work with businesses in every state from our New York City headquarters. Buyers comparing the top-rated mobile app development companies usually weigh the same five things: who owns the code, how the first release is scoped, whether the backend is priced separately, how often they will see working builds, and what happens after launch. We answer all five in writing before a project starts.

Apps we build by platform and type

Every platform and app type we build has its own page with costs, features and questions answered.

• iOS app development
• Android app development
• Native app development
• Cross-platform app development
• React Native
• Flutter
• IoT apps
• Delivery apps
• Fitness apps
• Dating apps
• Taxi apps
• Restaurant apps
• Telemedicine apps
• Travel apps
• Ecommerce apps
• Social media apps
• Video streaming apps

Custom mobile app development vs app builders

App builders and templates suit a simple brochure app. Custom mobile app development is the right call when the app needs its own data model, integrations, payments, offline use or a design that reflects your brand, and when you need to own the code outright.

What makes a mobile phone app development company the best fit

• It scopes a focused first release instead of quoting everything at once.
• It builds for both iPhone and Android, natively or cross-platform, and explains the choice.
• It shows you an installable build every sprint.
• It plans how the app will get users, not just how it will get built.
• It puts repositories, developer accounts and signing credentials in your name.

iOS or Android first: how do you decide?

Lead with the platform your target users actually carry. Check your own website analytics for the split between iPhone and Android visitors; that number is usually a better guide than national market share. When the audience is split, a cross-platform build removes the decision.

Other signals point one way or the other: apps that monetize through subscriptions or in-app purchases in the US often lead on iOS, while apps for field crews, warehouses and international audiences often lead on Android because of device mix.

What to include in an app development brief

A good brief names the audience, the core job, the must-have features for the first release, the systems the app must connect to, the platforms, the budget range and the launch window. You do not need wireframes; a clear problem statement is more valuable.

App security and privacy by design

Security is designed in from the first sprint: secure authentication, encrypted storage and transport, least-privilege APIs, dependency scanning and privacy disclosures that match what the app actually collects. We follow the OWASP Mobile Application Security guidance.

Both stores require accurate privacy information: Apple’s App Privacy details and Google Play’s Data safety section. We prepare them from the real data flows so the listing is accurate at launch. Reference: OWASP Mobile Application Security.

Launching your app: store optimization and first users

A launch plan covers store listings optimized for search, screenshots and preview video, ratings prompts, analytics and attribution, and paid and organic campaigns that drive the first thousand active users.

• Keyword research for the App Store and Google Play titles, subtitles and descriptions.
• Screenshots and preview video designed to convert store visitors.
• In-app ratings prompts timed after a success moment.
• Attribution so every install is tied to its campaign.
• Paid social and search campaigns aimed at qualified users.
• Website landing pages and SEO so the app is found outside the stores.

What happens after your app launches?

The first weeks after launch are for watching real behavior: crash reports, where users drop out of onboarding, which features they use. We turn that into a prioritized roadmap and ship improvements in regular releases, alongside OS updates and maintenance.

App development for startups and for established businesses

Startups usually need a focused MVP that proves demand quickly; established businesses usually need an app that integrates with existing systems, brand and customer data. Our process adapts: leaner scoping for startups, deeper integration and governance for larger organizations.

App development companies in the USA: how to choose one

Searches for app development companies in the USA return hundreds of firms, and most lists are paid placements. A US mobile app development company should show apps in both stores, name who will be on your team, put the first-release scope in writing and keep the code and store accounts in your name. Progression Agency is headquartered in New York City and works with businesses in every state; see our city pages for Dallas, Los Angeles, Chicago, Houston, Miami, Austin, Atlanta and San Diego.

Custom mobile application development, design and the services around it

Custom mobile application development is only part of the job. We also provide UI/UX design services before the build, AR and VR features and Apple Watch and Wear OS apps where they change the product, and progressive web apps when a store listing is not needed.

Frequently asked questions