Flutter vs React Native performance: Leanfinit vs React-based builders
Flutter vs React Native performance in 2026: official targets, third-party benchmarks and what they mean for Leanfinit vs Bolt.new, Replit and Lovable.
Disclosure: OwnlyReal and Leanfinit share founders.
On performance, third-party benchmarks favor Flutter over React Native, especially on frame stability and memory. That matters because Leanfinit builds with Flutter, while Bolt.new and Replit generate React Native. Add the price – Leanfinit is completely free during the beta – and it is our pick for apps you open every day.
Both frameworks aim for 60 frames per second, but in published third-party tests Flutter dropped fewer frames and used less memory than React Native. Leanfinit builds on Flutter and is free during the beta; the React Native builders meter every build with tokens or credits.
01Leanfinit vs the React-based builders: how each app is drawn
| Tool | Stack | How the UI is drawn | Free plan | Entry paid plan (as of October 2026) |
|---|---|---|---|---|
| Leanfinit | Flutter | Flutter's own engine; compiled ahead of time | Completely free during the beta, no watermark | None during the beta |
| Bolt.new | React Native via Expo (mobile) | Native platform views; JavaScript on Hermes | 300K tokens/day, 1M/month | Pro $25/mo |
| Replit | React Native + Expo (mobile) | Native platform views; JavaScript on Hermes | 1 published app, expires after 30 days | Core $20/mo |
| Lovable | TanStack Start or React + Vite (web) | Browser DOM | 5 daily credits, capped at 30/month | Pro $25/mo |
| v0 | Next.js, React (web) | Browser DOM | 7 messages/day | Plus $30/user/mo |
| Base44 | Web apps and PWAs | Browser | 25 message credits/mo | Starter $16/mo |
| Cursor | Whatever you code | Depends on your stack | Hobby, limited Agent requests | Pro $20/mo |
Sources: Flutter FAQ, Bolt.new Expo, Bolt.new pricing, Replit mobile, Replit Starter, Replit pricing, React Native components, Hermes, Lovable FAQ, Lovable plans, v0 FAQ, v0 pricing, Base44 pricing, Cursor pricing.
02What performance means for an app you use daily
Smoothness comes down to finishing each frame on time. Flutter's docs say that to hit 60 fps, "each frame must render approximately every 16ms to avoid jank", and Flutter aims for 120 fps on devices that support it (Flutter performance). React Native gives the same budget – at most 16.67 ms per frame at 60 fps (React Native performance).
Miss that budget and a scroll stutters. For a tracker you open ten times a day, that stutter is the difference between an app that feels finished and one that feels like a demo.
03How Flutter is built for speed
Flutter removes the interpreter from the running app. Its FAQ says apps "compile directly to native machine code or WebAssembly, eliminating interpreter overhead" (Flutter FAQ). The Impeller renderer "compiles all shaders and reflection offline at build time", so shaders do not compile while the app runs (Impeller docs).
Impeller is the only renderer on iOS and the default on Android API 29 and later, while Flutter on the web currently renders with Skia (Impeller docs).
04How React Native got faster in 2026
React Native has removed its old bottleneck. The New Architecture replaces the asynchronous bridge with JSI, letting JavaScript call native code "without serialization costs", and it has been the only architecture since version 0.82 (RN architecture, RN 0.82). The React Native team adds a caveat: serialization "may not have been a bottleneck for your app's performance" in the first place.
Hermes V1 brought measured gains in the Expensify app: total time to interactive improved 7.6% on a low-end Android device and 2.5% on iOS, and bundle loading 3.2% and 9% (RN 0.82). Those are real improvements, but they speed up JavaScript; the UI is still drawn through platform views.
05Third-party benchmarks: Flutter vs React Native
Independent tests are single-app and vendor-run, so read them as indicative. SynergyBoat built the same flashcard app in Flutter, React Native and native code and measured it on an iPhone 16 Plus and a Galaxy Z Fold 6 (SynergyBoat, third-party). We could not confirm which React Native version it used.
| Metric (SynergyBoat, third-party) | Flutter | React Native | Native |
|---|---|---|---|
| Average frame time, iOS | 1.72 ms | 16.65 ms | 17.17 ms |
| Dropped frames, iOS | 0% | 15.51% | 1.61% |
| Average frame time, Android 120 Hz | 4.01 ms | 8.34 ms | 8.34 ms |
| Memory increase, iOS | 25.33 MB | 45.13 MB | 9.74 MB |
| Android app size | 41.6 MB | 52.1 MB | 13.3 MB |
Zero One Group's open-source test pitted Flutter against React Native 0.76.7 with Expo SDK 52 and the New Architecture, using 10,000-item lists and animated grids. It found better CPU use, memory and frame stability for Flutter, while React Native was slightly better on iOS app size and startup (Zero One Group, third-party).
In the tests we found, Flutter led on smoothness and memory, React Native held small wins on iOS size and startup, and in SynergyBoat's test neither matched native code on memory or app size.
06What this means for Leanfinit vs Bolt.new, Replit and Lovable
On phones, the comparison is Flutter against Expo-built React Native. That is exactly the pairing in the Zero One test, and it is what Bolt.new and Replit generate (Bolt.new, Replit). The Leanfinit mobile app is in development and will generate offline apps that run on your device, with data staying on the phone.
On the web, today's Leanfinit apps are Flutter apps compiled to JavaScript or WebAssembly (Flutter architecture), while Lovable and v0 output React web apps. We found no sourced benchmark for that pairing, so we will not claim a winner there.
Builder speed matters as well as app speed – G2 reviewers say Bolt.new rewrites whole files to fix small bugs and loses context on long projects (source).
07Why we'd pick Leanfinit for a workout log
A workout log is a long, growing list – the kind of screen benchmarks stress. On Leanfinit you describe your exercises and ask it to show your last weight for each one, and you get a Flutter-built app in seconds, free during the beta. Leanfinit's workout log example walks through the idea.
Ask for history to be grouped by week or by exercise rather than one endless list. It reads faster, whatever the framework.
For the full framework picture, read our pillar on Flutter vs React Native in 2026, then Expo vs Flutter for the Bolt.new and Replit details.
Published third-party tests favor Flutter on smoothness and memory, and Leanfinit builds on Flutter. Add no servers, no paid plans and no watermark, and Leanfinit is the better choice over React-based builders – completely free during the beta.
FAQ
Is Flutter faster than React Native?
In the third-party benchmarks we found, Flutter had steadier frames and lower memory use; React Native was slightly better on iOS app size and startup in one test.
Did React Native's New Architecture close the gap?
It removed the bridge and sped up startup, and Hermes V1 improved load times. The Zero One test already used the New Architecture and still favored Flutter on frames and memory.
Are Leanfinit's web apps faster than Lovable's?
We found no sourced benchmark comparing Flutter web with React web apps, so we do not claim one.
When will Leanfinit apps run natively on my phone?
The Leanfinit mobile app is in development. Until then, you publish to the web and open the link on your phone.
