Engineering teams that build, release and maintain iOS and Android apps, in Swift and Kotlin or with Flutter and React Native, and show that work on their own sites
Last updated: November 9, 2026. Written by Nick Babich.
A mobile app is not finished when the screens are approved. Someone has to write the Swift or Dart, connect the app to payments and accounts, survive App Review and the Google Play target API deadline, and keep shipping updates when the operating systems change every year. That is the work this page is about: hiring a mobile app development agency to build and run the app, not only to design it.
I built this shortlist for founders, product leaders and CTOs who are choosing an engineering partner for a new app, a rewrite or a migration to a cross-platform stack. An agency made the list only if its own website shows a named app it built, rebuilt or migrated, with the engineering scope described: platforms, frameworks, backend or SDK work, testing and release. A portfolio of beautiful app screens without development did not count. If you only need product and UX design, my separate list of mobile app UX design agencies is the better starting point.
Nine mobile app development companies passed. Very Good Ventures and LeanCode lead on Flutter, Callstack, Software Mansion, Infinite Red and thoughtbot on React Native, and Miquido, STRV and MindSea show native iOS and Android builds. Below: the proof behind each pick, my scores, costs, and how to choose.
Editorial note: No agency paid for placement, and I excluded agencies that currently pay app-development directories for sponsored or featured spots in this category. Scores are my editorial assessment out of 5, based on the evidence linked in each profile.
What I checked: published proof that the agency wrote and shipped the app, not only designed it. I read each agency's app cases on its own site, checked Clutch for prices and team size, and scored every team against eight development criteria.
The case had to name the client and the app and say what the team built: a new app, a rewrite, a module, a migration or a set of SDKs. A design case with no development scope earned no points on its own.
I gave credit for Swift, Objective-C, Kotlin and Java work and for platform features such as widgets, Live Activities, App Clips and native video, because cross-platform apps still need native code at the edges. Miquido's Skyscanner module and Software Mansion's Partiful work show this directly.
Flutter and React Native let one team ship both stores from one codebase. I looked for evidence that the agency shipped both platforms together and kept feature parity, as in Very Good Ventures' Hamilton app.
Most app problems come from the server side: accounts, payments, real-time data and third-party services. I scored agencies higher when they built or integrated the backend, such as STRV's client SDKs for Major League Soccer.
Many buyers are not starting from zero. I gave credit for moving an existing app to a new stack while it kept shipping, which Callstack documents for AutoZone.
Apple and Google both review what you ship. I looked for testing practice, beta channels such as TestFlight, and release discipline that keeps an app inside store rules.
An app needs updates every year when iOS and Android change. I gave credit for agencies that still run the apps they built or describe ongoing maintenance.
Banking, health and live-event apps add data residency, identity checks and traffic spikes. I scored agencies higher when their cases show they delivered under those constraints.
Each profile names the development work the agency publishes on its own site. Clutch figures come from Clutch profile text read on November 9, 2026; where a figure was not published, I say so.
Best for (mobile app development): companies that want a Flutter app on iOS and Android at the same time, and a team that keeps running it
Clutch: $100,000+ minimum, $150–199/hr, 10–49 people, 5.0 from 35 reviews
Very Good Ventures' Hamilton case is the clearest cross-platform build on this list. The official app for the musical had to open the daily ticket lottery on iOS and Android together, inside a fixed budget. VGV built it in Flutter in three months and launched both platforms the same day with full feature parity; the agency calls it the first commercial Flutter app outside Google. Firebase and Google Cloud run the backend, with Cloud Functions on lottery logic, merchandise and content. The case reports more than 100 million lottery entries, and VGV says it still runs the app.
Why I would shortlist Very Good Ventures
Same-day iOS and Android launch under a fixed budget is hard, and still running the app years later is rarer. That combination is what I want when Flutter has to carry a live consumer product, not a demo.
Best fit
Verify before hiring
Score: 4.9
Best for (mobile app development): enterprises moving existing iOS and Android apps to React Native without pausing releases
Clutch: minimum and hourly rate not shown in the profile text I read; most common project size $50,000–$199,999 (2 reviews); 50–249 people
Callstack's AutoZone case covers replacing two native codebases while the app keeps shipping. AutoZone, a retailer with more than 7,000 stores, could not match its web feature pace with separate iOS and Android teams. Callstack migrated incrementally, starting with the least dependent modules, and built a custom bridge so React Native and remaining native screens could share data. It shipped a redesign, push and payments inside a two-week release cycle. The case says the 18-month migration missed no releases, the Google Play rating rose from 4.2 to 4.6 and later 4.7, and the mobile user base more than doubled. These are agency-published figures.
Why I would shortlist Callstack
Most React Native rewrite pitches assume a freeze. AutoZone kept a two-week release cycle for 18 months. That release discipline is the proof I care about for a live retail app.
Best fit
Verify before hiring
Score: 4.8
Best for (mobile app development): consumer platforms that need a native iOS and Android module built to the standard of a large existing app
Clutch: $25,000+ minimum, $50–99/hr, 50–249 people, 4.9 from 51 reviews
Miquido's Skyscanner case describes a car rental module built from scratch for iOS and Android. The first version converted poorly and felt like a desktop UI, so Miquido rebuilt it natively in Objective-C and Java. Location led the search via MapKit and the Google Maps API, with filters across 30,000 locations and last-minute booking. The architecture worked as a standalone app and as a module inside Skyscanner's travel app. Miquido states the module brought more than one million new users and grew into a third of Skyscanner's business; treat those as the agency's figures.
Why I would shortlist Miquido
Rebuilding a weak module inside a flagship consumer app, natively on both platforms, is a different skill from shipping a greenfield MVP. The dual standalone-and-embedded architecture is what I look for when your product already has a large audience.
Best fit
Verify before hiring
Score: 4.8
Best for (mobile app development): media, sports and consumer brands that need iOS, Android, backend and QA engineers in one team
Clutch: $100,000+ minimum, $100–149/hr, 50–249 people, 4.8 from 60 reviews; most common project size $200,000–$999,999
STRV's Major League Soccer case lists a full delivery team: product, design, iOS, Android, backend and QA. Engineers first stabilized a legacy app under demand — refactoring the codebase and adding rigorous QA so fans got real-time updates without crashes. STRV then rebuilt the experience and shipped three client SDKs for real-time stats and consent-aware user data, the content catalog, and secure fan identity, plus an integration with MLS's real-time data pipeline and Sidekick AI (retrieval-augmented). The case publishes no performance metrics, so ask for crash and release data.
Why I would shortlist STRV
Sports and media apps fail on the backend as often as on the UI. One team covering iOS, Android, SDKs, identity and QA is the shape of engagement I want when live scores and fan accounts cannot go down on match day.
Best fit
Verify before hiring
Score: 4.8
Best for (mobile app development): banks and regulated companies that need a large Flutter team inside a multi-vendor program
Clutch: $25,000+ minimum, $50–99/hr, 50–249 people, 5.0 from 40 reviews; most common project size $50,000–$199,999
LeanCode's Credit Agricole case covers CA24 Mobile, a retail banking app for iOS and Android built in Flutter. The bank ran twelve squads with several vendors on backend, infrastructure and testing. LeanCode led the Flutter chapter; its team of 14 Flutter developers implemented the bank's design system and parts of the customer journey, including Know Your Customer account opening and the product cards on the dashboard. Design and backend came from other vendors, so this proves Flutter engineering at scale in a regulated program rather than end-to-end ownership.
Why I would shortlist LeanCode
Banking apps are rarely built by one vendor. Leading a 14-person Flutter chapter inside a twelve-squad bank program is the proof I want when your compliance and backend already sit elsewhere.
Best fit
Verify before hiring
Score: 4.7
Best for (mobile app development): React Native apps that need native iOS and Android features nobody else has packaged yet
Clutch: $10,000+ minimum, $100–149/hr, 250–999 people, 4.8 from 24 reviews
Software Mansion's Partiful case shows the native work inside a React Native app. Partiful wanted iOS and Android feature parity. Software Mansion built transparent Android video with a custom TextureView and OpenGL, replaced costly blur with a gradient, and added iOS Live Activities via WidgetKit and custom Swift / SwiftUI modules. It also shipped an App Clip under 50 MB, refactored a monolithic data context that caused re-renders, and supported Expo upgrades, with end-to-end testing across targets. Partiful's store awards belong to the client, not the agency.
Why I would shortlist Software Mansion
When React Native hits a wall — Live Activities, App Clips, custom OpenGL video — you need engineers who write the native modules, not only the JavaScript. That is the gap this case fills.
Best fit
Verify before hiring
Score: 4.7
Best for (mobile app development): established brands that want a React Native MVP built with discovery and user testing, then handed over
Clutch: $10,000+ minimum, $150–199/hr, 50–249 people, 4.9 from 39 reviews
thoughtbot's Harvard Business Review case, published on its own site, describes a new app for a publisher whose younger, more global readers expected a premium mobile experience. The old app was disconnected from HBR's systems. thoughtbot ran discovery and user testing, then built a React Native app that unifies payment and subscription with the website and HBR's vendors. Its mobile director chose React Native for cost, speed and maintainability. The nine-month engagement used designers who also write code and gradual knowledge transfer so HBR owns the product afterward. No usage metrics are published.
Why I would shortlist thoughtbot
Many studios ship an MVP and leave. A nine-month engagement with discovery, vendor coordination on payments, and deliberate knowledge transfer is the shape I want when your internal team must own the app next year.
Best fit
Verify before hiring
Score: 4.6
Best for (mobile app development): companies with a popular app that needs a React Native rewrite without losing its users
Clutch: $100,000+ minimum, $200–300/hr, 10–49 people, 2 reviews (no rating shown on the profile text I read)
Infinite Red's GasBuddy case covers a full rewrite of a widely used fuel-price app, ten years after its last overhaul. GasBuddy's engineers chose React Native and wanted senior specialists to move every user to the new app safely. Infinite Red worked with GasBuddy's mobile team every day to prioritize, implement and test the iOS and Android rewrite, and tuned performance so the polish stayed. GasBuddy's CTO credits them with avoiding the "dark alleys" of state management, performance and third-party modules. This is team augmentation, not a turnkey build, and the case gives no date or metrics — ask for both.
Why I would shortlist Infinite Red
Rewriting a popular app is where users leave if performance dips. Pairing senior React Native specialists with the client's own mobile team every day is the model I want when you cannot pause the product.
Best fit
Verify before hiring
Score: 4.6
Best for (mobile app development): health companies that need a native app plus clinician and patient portals, with data stored in the right country
Clutch: $10,000+ minimum, $150–199/hr, 10–49 people, 5.0 from 47 reviews; most common project size $50,000–$199,999
MindSea's Constant Health case is a weight-management program built with a bariatric medical institute. MindSea shipped a native iOS app for food logging, goals, recipes and clinician phone or video calls, plus two React portals: one for patients to sign up, pay and book, and one for coaches and dieticians to set goals, review progress, message patients and view analytics. Patient data had to stay on Canadian servers. Navigation followed Apple's Human Interface Guidelines for a non-tech-savvy primary user, with design, user testing, launch and post-launch in scope. The case is iOS only — ask for Android references if you need both.
Why I would shortlist MindSea
Health products rarely stop at the phone. A native patient app plus clinician and patient portals, with data residency called out up front, is the shape of delivery I want in regulated care workflows.
Best fit
Verify before hiring
Score: 4.5
The chart scores all nine agencies on five development criteria and an overall score, each out of 10. Very Good Ventures and Callstack lead on shipped build proof, cross-platform delivery and release discipline, Miquido and Software Mansion lead on native iOS and Android depth, and STRV and Very Good Ventures lead on backend and integrations.
Hire a native team when the app depends on platform features, heavy graphics or the newest Apple and Android APIs on day one; hire a Flutter or React Native team when you need both stores from one codebase and one team. Most agencies here work in one stack first, so choose the stack before you choose the agency.
Native (Swift and Kotlin or Java). Two codebases give full access to each platform and the fewest workarounds, at the cost of two teams for the life of the app. Miquido's Skyscanner module and MindSea's Constant Health app are native builds.
Flutter. One Dart codebase renders its own interface on both platforms, which suits brand-heavy apps and design systems that must look the same everywhere. Very Good Ventures and LeanCode are Flutter specialists.
React Native. One JavaScript or TypeScript codebase uses native components and can be introduced screen by screen into an existing native app. Callstack, Software Mansion, Infinite Red and thoughtbot all publish React Native work.
A quick test: if your web team already writes React and you have an existing native app, a React Native migration partner is usually the shortest path. If you are starting fresh and the interface is the product, compare Flutter teams. If one platform feature is the whole business, stay native.
Choose the agency whose published builds match your stack and situation (new app, rewrite, migration or new module), then test how it handles backend work, releases and the year after launch.
A new consumer app, a migration of a large native app and a module inside an existing platform need different teams. Very Good Ventures fits new cross-platform launches, Callstack and Infinite Red fit migrations and rewrites, and Miquido fits modules inside large apps.
Find out whether the agency builds the API, integrates yours or expects another vendor to do it. STRV's SDK work and Very Good Ventures' Firebase backend are owned by the agency; LeanCode's banking work relied on other vendors' backend services.
Ask how often the agency ships, how it uses TestFlight and Play testing tracks, and what happened in its last rejected submission. Callstack's AutoZone case is a useful benchmark: no pause in a two-week release cycle during a long migration.
iOS and Android change every year, and Google Play sets a minimum target API level for new apps and updates. Ask who handles OS upgrades, crash monitoring and dependency updates, and whether the same engineers stay on.
Some teams here, such as thoughtbot and MindSea, design and build. Others, like LeanCode on the bank's program, implement an existing design system. Decide before you compare quotes.
A strong proposal names the stack and why, the backend and integration plan, the testing and release process, and who supports the app after launch. Expect these items:
Mobile app projects differ more by build type than by industry: a Flutter launch, a native module and a React Native migration need different skills. The table maps eight build types to the engineering focus, a question to settle before hiring, and agencies to start with.
With these agencies, a focused build or feature sprint starts around $10,000 to $25,000, and a full app or flagship program usually starts at $50,000 to $100,000 or more, based on Clutch minimums read in November 2026. Treat these as planning floors, not quotes.
Costs rise with a second native platform, every integration (payments, identity, real-time data), regulated data handling and the support period after launch. Fixed price suits a clearly scoped MVP slice; a dedicated team or retainer suits an app that ships every sprint; time and materials suits migrations and rewrites, where the unknowns sit in the old code. Very Good Ventures, for example, publishes a fixed fee for a first "quick win" scope and effort-based pricing for projects and ongoing partnerships.
A mobile app development project starts with technical discovery and ends with an app that someone keeps updating after it reaches the stores.
These four graphs show how each agency works, not how it ranks, on 0–10 axes: marketing-driven vs product-focused (brand and design studio vs engineering firm), ideation vs execution (discovery and strategy vs build and release), usability vs aesthetics (task research and platform conventions vs visual craft), and low vs high price (published minimums and rates).
Walk away from an agency that shows only app screens and no shipped builds, or that cannot tell you who will maintain the app after launch.
Key Takeaways
Got questions? We've got answers.
Contact us
If you have any questions or you want your agency to be considered for listing with us, please feel free to contact us.
The form has been successfully submitted.
