React Native staff augmentation
React Native developers who treat mobile as its own discipline, not a side effect of knowing React
· Average time to first PR: 12 days
Most teams do not need another JavaScript developer who has tried React Native on a weekend project. They need someone who has actually shipped to the App Store on a Sunday night, debugged a gradle build that broke three hours before release, and knows what a stuck Hermes bundle looks like in production.
That is the kind of engineer we place. Siblings Software is a small Argentine firm that has been staffing mobile teams for companies in the US, Canada, UK, and Spain since 2014. This page is for you if you are evaluating whether to hire us, so it is written to answer the questions buyers actually ask — rates, process, tradeoffs, and where we are honestly not the best fit.
Who actually hires React Native developers from us
Four buyer profiles account for about 90% of the engagements.
Product companies with a growing app and one overwhelmed mobile lead
Your web team is five to fifteen engineers, but mobile is a single person who started the app and now cannot ship features fast enough. You do not need another body — you need a mid or senior engineer who can pair with your lead, take ownership of a feature area, and not drag them into code reviews all day.
Funded startups that raised to build a mobile product and do not have a CTO who wants to hire mobile
Classic Series A or seed-extension situation. The founders know the domain, not Swift. You want a small squad that can take a Figma file and a backend and turn it into a shipped app — stores included — in under five months, without you having to interview for three months.
Agencies and consultancies that sold a mobile project and do not want to bench staff
You win a fixed-scope mobile build twice a year. Hiring in-house React Native people means paying them between projects. We are your flex capacity — you keep the client relationship, we plug one to four engineers into your delivery squad.
Established companies modernizing an old native iOS / Android stack
You have an app written in Objective-C in 2016 and a separate Android app nobody wants to touch. Leadership has agreed React Native is the answer, and now someone has to do the actual work — usually in parallel with the old apps still being maintained. We have done this migration four times and can tell you what will go wrong before it does.
If none of those sound like you, we will probably still take a discovery call, but it is fair to tell you in the first fifteen minutes if we are the wrong vendor.
What these engineers actually do day-to-day
The short version is "whatever your mobile roadmap says." The longer version is worth reading, because the skill gap between a React developer who has used React Native and a real mobile engineer shows up here.
Native modules and the bridge
Writing Swift or Kotlin when JavaScript runs out. Typical tickets: wrapping a biometric library that only ships native SDKs, exposing a BLE peripheral API, piping a camera frame through ML Kit without copying it three times. They understand the old bridge, the new TurboModule architecture, and when it makes sense to migrate.
Release engineering
Fastlane or Expo Application Services (EAS) pipelines, certificate and provisioning profile hygiene, phased rollouts, TestFlight groups, internal testing tracks, and the phone calls you make when Apple flags 4.3 (a) for the third time on a Friday. Boring work. Critical work.
Performance and memory
Measuring with Flipper, React DevTools Profiler, Xcode Instruments, and Android Profiler. Common fixes we ship: replacing FlatList with FlashList on dense lists, moving image decoding off the JS thread, memoizing selectors, tracking down memory leaks in native modules, and getting cold-start under two seconds on mid-range Android devices.
Offline-first and sync
Most serious mobile apps need to work on a subway. That means local-first data stores (MMKV, WatermelonDB, SQLite), conflict resolution when the user comes back online, and background sync that survives OS restrictions. React developers from the web rarely think about this until week three.
Platform differences that bite
Push notification payload limits, iOS background execution windows, Android Doze mode, the three different ways deep links work, WebView edge cases, keyboard avoidance that is genuinely different on the two platforms. Not glamorous, but each one is a half-day bug hunt if the engineer has not seen it before.
OTA updates without shipping broken apps
Expo Updates, CodePush, or EAS Update for shipping JavaScript fixes without a store review. We use them, but we also know when Apple considers an OTA an app resubmission under the App Store Review Guidelines. The line is real.
Every developer we place has shipped at least one React Native app end-to-end on both stores. That is the minimum bar. Most have three or more, across fintech, health, retail, and media.
Engagement models and what they cost
We publish ranges because secret pricing is a waste of everyone’s time. The final number depends on seniority, English level (some clients pay a premium for engineers who are genuinely fluent), and whether you need a specific native module specialist.
Single engineer, month-to-month
One vetted React Native developer integrated into your team. You run standups, sprints, and reviews. We handle contracts, equipment, and replacements if needed.
Notice to end: 15 days after the first month.
Small squad with QA
Two engineers plus a mobile QA who tests on real devices. Works well when you are launching or rescuing an app and want coordinated output rather than three separate contributors.
Minimum: 3 months to justify ramp-up.
Tech lead owning mobile
A senior lead plus two to four engineers. The lead owns architecture, release cadence, and hiring decisions. Best when you have no internal mobile capability and do not want to build one right now.
Minimum: 4 months.
Numbers assume 40-hour weeks, senior and mid-level mix, and include recruiting, laptops, benefits, and local taxes. They do not include third-party services like Sentry, RevenueCat, or App Store developer program fees — those stay on your accounts so you control them.
How the hiring process actually runs
From the first email to a merged pull request in about two weeks.
- Discovery (day 1 to 2). 45-minute call. We ask about your app (Expo or bare? Architecture? Native modules?), the team shape, seniority, time zones, and what success looks like in 90 days. If the fit is wrong, we say so here.
- Shortlist (day 3 to 5). You get 2 to 3 profiles with written background notes and a Loom from the engineer walking through a recent React Native project. No "anonymous resumes," no wasted interviews.
- Your interview (day 5 to 8). You run it the way you want — live coding, system design, culture chat, or all three. We join the first one if helpful, otherwise we stay out. Decision in 48 hours.
- Onboarding (day 8 to 12). Laptop, repo access, Apple Developer invite, Android signing keys, Sentry, Firebase, CI credentials. We have a checklist so nothing is missed. Engineer pairs with yours on the first ticket.
- First PR merged (day 12 to 15). Something real: a bug fix, a small feature, an infrastructure improvement. The point is to validate the workflow, not to impress.
- Replacement window (first 14 days). If the match is wrong, we swap at no cost and carry the overlap. After that, 15-day notice either way. Contracts are month-to-month beyond any agreed minimum.
Siblings vs freelancers vs in-house vs generic offshore
Most of our prospects have already tried at least one of the other options. Here is an honest comparison. If a row does not match what you are seeing on your own, tell us — we will adjust.
Where freelancers win
Short, well-scoped tasks. A single native module, a tricky animation, a performance audit. If you know exactly what you need and it is under 80 hours, a specialist freelancer is often cheaper and faster than anyone else.
Where freelancers hurt
Anything that needs continuity. They take vacations without warning, juggle three other clients, and rarely do the unglamorous work — release pipelines, documentation, runbooks — because it is not billable in an obvious way.
Where in-house wins
Core product ownership. If mobile is your permanent center of gravity, a full-time employee who will be there in five years is irreplaceable. We have clients who start with us and then hire from their own team once they know what "good" looks like. That is fine.
Where in-house hurts
Time and regret. In the US market, a senior React Native hire is a three-to-four-month process, often failing the first time. Meanwhile the roadmap stalls. And if the hire turns out to be the wrong fit, you are looking at a severance conversation.
Real hiring scenarios we see repeatedly
These are composites from actual engagements — specifics anonymized, numbers rounded. They are here because buyers often want to know "is my situation a thing you have seen before."
Scenario A — the crashing fintech
Context: US consumer lending app, 400k monthly active users, crash-free rate under 97% on Android. Two in-house devs, one on parental leave.
What we did: Placed one senior within 9 days. First 30 days: read-only, instrumented with Sentry and Firebase Performance, wrote a runbook. Days 30 to 90: rewrote the flaky lending flow, fixed three native-module memory leaks, moved image handling off the JS thread.
Outcome: Crash-free rate to 99.6% on Android, 99.9% on iOS, p95 cold start from 3.8s to 1.9s on a Pixel 6a.
Scenario B — the MVP that needed to ship
Context: Seed-funded logistics startup, Figma ready, backend half built, zero mobile engineers. Investors promised an app by Q2.
What we did: Small squad — one senior, one mid, one mobile QA — plus 10% of a tech lead for architecture reviews. Expo bare workflow, EAS for builds.
Outcome: 19 weeks from kick-off to both stores live. TestFlight beta at week 11. Post-launch, squad reduced to one engineer for maintenance.
Scenario C — the legacy replatform
Context: European retailer with an Objective-C iOS app from 2016 and a Java Android app that only one person understood. Leadership wanted one codebase.
What we did: Tech lead plus three engineers over 10 months. Brownfield React Native embedded in the old apps, screen by screen, using RCTRootView. The native apps kept shipping while new features moved to RN.
Outcome: 82% of screens on React Native at hand-off, with their own team continuing migration. Two of our engineers were hired directly by the client at the end — we do not have non-competes.
Scenario D — the agency overflow
Context: US-based digital agency had sold a 4-month React Native build and their senior mobile person had just quit.
What we did: Two engineers under their delivery lead, white-labeled on their side (our contract with the end client was never visible). Daily standups in the agency’s Slack, PRs in their GitHub.
Outcome: Project shipped on the original deadline. Agency brought us back three more times in the following 18 months.
Mini case study
How one engineer cut a telemedicine app’s video setup time in half
Client. A Series B telemedicine company serving around 90,000 monthly consultations across the US. Their React Native app was stable but users consistently abandoned video calls in the first 15 seconds — roughly 11% churn at that single funnel step.
Brief. Hire one senior React Native engineer who could live inside the mobile pod for six months, own video call reliability, and not need hand-holding on native code.
What we did. Placed a senior with prior WebRTC work. First two weeks: instrumented the call flow end-to-end with custom Sentry breadcrumbs, discovered that 38% of failures came from iOS camera permission prompts being triggered too late and 22% from Android audio focus conflicts. Rewrote the pre-call permissions flow as a native module (Swift on iOS, Kotlin on Android), cached device capabilities, and moved WebRTC initialization off the JS thread.
Result over 90 days. Abandonment at the video connect step went from 11% to 4.2%. Median time from "start call" to "first video frame" dropped from 6.3 seconds to 2.9 seconds. Customer support tickets tagged “video not working” fell by about 60%.
Honest caveat. A chunk of the win came from just instrumenting properly — something their team could have done if they had the capacity. The value we added was having an engineer who knew where to look on day three.
At a glance
Industry: Telehealth
Engagement: 1 senior, 6 months
Stack: React Native 0.73, Expo bare, WebRTC, Swift, Kotlin, Sentry
Abandonment: 11% → 4.2%
Time to first frame: 6.3s → 2.9s
Support tickets: -60% for video issues
The risks of hiring React Native developers, and how we handle them
Any vendor who tells you staff augmentation is risk-free is either lying or new. Here are the four things that actually go wrong, and what we do about them.
Risk: the engineer looks great on paper and stalls in week three
How we handle it. Two-week replacement window, free. Our vetting includes a live pair session on a real mobile bug, not a Leetcode problem. And our account lead checks in with you at day 14 specifically to ask: "if this was a full-time hire, would you keep them?"
Risk: knowledge walks out when the engagement ends
How we handle it. Documentation is a non-negotiable line item, not a favor. Every native module gets a README. Every tricky decision gets an ADR. Runbooks for release pipelines live in your repo. If you end the engagement tomorrow, your team has the map.
Risk: the React Native version you are on becomes unsupported
How we handle it. Before we sign, we check your current version against the official React Native release page. If you are more than two minor versions behind, we will flag it and propose an upgrade path — usually incremental, using the community upgrade helper, not a big-bang rewrite.
Risk: App Store rejection on a critical release
How we handle it. Release notes, privacy manifests, and tracking domain declarations are prepared a sprint in advance, not the night before submission. Our senior engineers have each handled multiple rejections under guidelines 2.1, 3.1.1, and 5.1.1 — the three that trip up most React Native apps — and know what Apple typically accepts.
Why Siblings Software specifically
Decide based on facts, not slogans.
11+
Years staffing mobile teams
Founded 2014 in Córdoba, Argentina
40+
Apps shipped on both stores
Across fintech, health, retail, logistics
GMT-3
Argentina timezone
Overlaps fully with US Eastern
We are deliberately small. There is no sales org pushing headcount. The founders — one of them, Javier Uanini, still does most discovery calls personally — review every engagement. Our engineers speak to clients directly from week one. That is the actual reason onboarding is fast: there is nobody in the middle translating.
Things buyers usually get wrong when shopping for a vendor: asking for an hourly rate before explaining the work (you will be quoted the lowest possible number and the real cost will arrive later), insisting on seeing full CVs before any call (we will not share personal data before you have signed a basic NDA, and neither should you want us to), and believing that a bigger agency means more reliable delivery (in mobile, small and specialized beats large and generic almost every time).
Frequently asked questions from buyers
Our standards
Mobile done like it is the main product, not a side quest.
- Real devices, every sprint. Simulators lie about performance. Our QAs keep a small rack of iPhones, Pixels, and a deliberately underpowered Android to catch the issues affluent users never see.
- Instrumentation from day one. Sentry, Firebase Performance, or your tool of choice, configured before the first feature ships. You cannot fix what you are not measuring.
- Releases as a product. Pipelines, changelogs, staged rollouts, and store metadata are owned by the squad, not assumed to be "someone else’s problem."
- Written artifacts. ADRs for architectural decisions, READMEs for every native module, runbooks for common production incidents. This is what makes the handover painless if we ever leave.
- Honest escalation. If a timeline is slipping or a technical choice was wrong, we will say so in the weekly update, not at the end of the sprint.
Talk to Siblings Software
Tell us about your app. We will reply within one business day, or say so if we are the wrong fit.