Mobile app development in New York
New York's buildings are run by supervisors and technicians who spend the day in basements, boiler rooms and stairwells, where the signal drops and a paper work order is still the tool that never fails. Property managers who try to replace it learn the same lesson quickly: an app that needs a connection to save a note is abandoned within weeks.
We build React Native apps for both stores that save first and sync later. Work orders, photos and sign-offs are stored on the phone and sent when the connection returns, with conflicts settled by agreed rules rather than by whoever saved last. We know the shape of this work: FM360, the facilities platform in our case studies, has a mobile app for supervisors on the floor and a phone page for technicians, on the same backend as the office web app. The backend expects clients that run an old version for months, because nobody updates an app halfway through a shift.
Most software bought in New York is bought by companies that do not think of themselves as software companies. Banks, insurers, asset managers, publishers, agencies, fashion houses and property firms all run on systems that sit beside the real business: a client portal, a pricing engine, a reconciliation job, a content pipeline. Those systems rarely start from nothing. They connect to a vendor platform, a core system older than the team, and a folder of spreadsheets someone updates by hand, and the brief is usually to make all three agree.
What those companies need built follows the industry. Asset managers and insurers need client portals where a family office sees two funds and not a third, and overnight jobs that reconcile custodian, market data and order feeds before the market opens. Publishers and ad-tech firms need event pipelines whose delivery numbers agree across vendors, and front ends that stay fast under the ad stack. Property firms need apps for technicians working in basements with no signal. And founders who left one of these industries need a first version in front of a pilot customer before the interest cools.
Hiring is the constraint. Engineers here are courted by banks, big tech offices and funded start-ups at the same time, and Built In puts the average software engineer base salary in the city at about $160,000 before bonus. The shape this produces is a small in-house team that keeps the core systems running, and behind it a list of well-defined projects that nobody on that team will reach this year. That list is where we are useful: each project is a defined piece of work, it starts with a fixed-price two-week piece, and the code belongs to you from the first commit.
We are in Bengaluru and move our working day for New York. Four hours of every working day overlap with your morning in Eastern time, stand-up included, so decisions and code review happen live with the engineer who writes the code. Runbooks and architecture notes are written as we go, so your in-house team can run what we build long after the project is finished.
We are the right fit for the defined projects your in-house team is too stretched to reach this year: a client portal, a reconciliation job, an event pipeline, a first version for a pilot customer. Senior capacity starts within days, the first piece is a fixed-price two-week engagement, and agencies can ship the work under their own name.
Four ways this arrives.
And crashes on the ones your users own. We add crash reporting with readable stack traces, find the handful of devices and OS versions causing most of the crashes, and fix those before anyone touches a feature.
Signing keys on a laptop, a manual build, store notes written at midnight. We move builds and signing into CI, add over-the-air updates for JavaScript-only fixes, and write down exactly how a release goes out.
A Bluetooth device, a vendor SDK, a camera pipeline, a background task the OS keeps killing. We write the native module in Swift and Kotlin, expose a small typed interface to React Native, and keep it isolated so upgrades stay possible.
Forms that vanish, actions that send twice. We decide what must work offline, keep it on the device, queue writes with idempotency keys the backend understands, and show the user plainly what is still waiting to sync.
Our own React Native app on Android, with retraction built into the client because moderation can pull a message after it has been sent.
Read the write-up →Asked by New York teams.
How do you work with teams in New York?+
We are in Bengaluru and move our working day for New York, so four hours of every working day overlap with your morning in Eastern time, stand-up included. Calls, reviews and decisions happen in that window, and the rest of the conversation runs in your tools: Slack, GitHub, Linear. The person on every call is the engineer who writes your code, and the code sits in your repositories from the first commit.
Do you build for New York financial firms?+
Yes. The work is usually the systems beside the trading or underwriting desk: overnight jobs that reconcile custodian, market data and order feeds before the open, client portals where investors, brokers and their accountants each see exactly what they should, and internal tools that replace a pricing or renewals workbook only one person understands. We build them to be idempotent and traceable, so every figure can be followed back to the file it came from.
How does your rate compare to hiring in New York?+
Built In puts the average software engineer base salary in New York City at about $160,000, before bonus and benefits. Our published rate is $35/hour, or $5,400 a month for an embedded engineer, with a $5,000 minimum. There is no recruiting time and no employment overhead, and work starts within days of the call. The first piece is a fixed-price two-week engagement at $2,800, so you judge us on working code.
Can you take over a system another vendor built?+
Yes. In New York that is often a client portal or an internal tool built by an agency that has since moved on, with nobody in-house who knows how it runs. We start by reading the code and running it, then write down how it works and where it is fragile before changing anything. A good first two-week piece makes the riskiest part safe and leaves your team runbooks it can use.
React Native or fully native?+
React Native for most products: one codebase, one team, both stores. Fully native makes sense when the app is mostly the hard native part, such as heavy camera or audio processing, complex background work, or a platform feature React Native does not support yet. We will tell you which side of that line you are on, and write the native parts by hand either way.
Expo or bare React Native?+
Expo, in almost every case now. Development builds and config plugins removed most of the old reasons to eject, and EAS handles builds and signing. We go bare only when a native dependency genuinely cannot live inside a config plugin, and we will explain why before doing it, because it makes every future upgrade more work.
Can you take over an app someone else built?+
Yes. We start by getting it to build on a clean machine, which is often the hardest step, then bring React Native and its dependencies up to a supported version before adding features. We tell you what state the app is in, including where the store listings, signing keys and accounts actually live, before quoting anything larger.
Who handles App Store and Play Store submission?+
We do, from your developer accounts, not ours. We prepare the builds, the privacy disclosures and the notes for the reviewer, and deal with rejections when they come. The accounts, signing keys and listings stay in your name, so you can change developers later without asking anyone's permission.
Does our backend need to change for a mobile app?+
Often, a little. A mobile client stays on old versions for months, retries on bad networks, and cannot be fixed by a server deploy. That means versioned endpoints, idempotent writes, and a way to tell an old client it must update. We check the backend for those before the first screen is built, because retrofitting them after launch is slower.