How Android Apps Handle Real-Time Local Processing
Android's on-device machine learning stack lets apps run inference, image recognition, and text processing locally without sending data to servers, reducing latency and protecting privacy.
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79 posts about Android. Every summary links to the original.
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Getting started with Flutter authentication
This tutorial shows how to add Google authentication to a cross-platform Flutter application using the Supabase SDK for Flutter. It explains OpenID Connect as a protocol built on OAuth 2.0, then configures Google Cloud client IDs for iOS, Android, and web, with Supabase using the web client ID to verify the supplied identity token. The sample initializes Supabase, starts Google sign-in through google_sign_in, passes the resulting access and ID tokens to signInWithIdToken, and listens for signed-in events to navigate from LoginScreen to ProfileScreen. The profile reads avatar_url and full_name from Supabase userMetadata, while a sign-out action returns the user to the login screen, producing a basic personalized app.
Native Mobile Auth Support for Google and Apple Sign in
Supabase has expanded its authentication support for native Apple and Google sign-in on iOS and Android, addressing a flow that previously required developers to send users through a web browser. Native apps built with Flutter or React Native can use OS-provided authentication dialogs across Apple platforms including iOS, macOS, tvOS, and watchOS, while Android support covers all Android variants. Behind these methods, ID tokens issued by Apple or Google are validated by Supabase Auth to create accounts or link existing accounts based on email similarity. The same signInWithIdToken() method also enables Sign in with Apple JS, Google One Tap, and authentication in Chrome extensions; the Google One Tap example passes the provider’s credential and a matching nonce when one is supplied via data-nonce.
How to Add Authentication to .NET MAUI Apps
This tutorial shows how to add Okta-based authentication to a .NET MAUI application, covering project setup, OpenID Connect configuration, sign-in, sign-out, and platform integration. It uses IdentityModel.OidcClient, an OktaClient wrapper, an OktaClientConfiguration class, and a WebBrowserAuthenticator implementation to connect the application to Okta’s browser-based authorization flow. The walkthrough creates a native OIDC client with the Okta CLI, registers redirect and logout URIs using myapp://callback, configures dependency injection, and updates the UI to display claims after login. For Android, it adds a WebAuthenticationCallbackActivity with an intent filter for the myapp scheme and enables Custom Tabs visibility in AndroidManifest.xml. The post includes troubleshooting for NuGet configuration and runtime-pack errors, but notes that the Okta CLI was deprecated and the original instructions no longer work exactly as written after the May 2025 plan change.
Securing your Flutter apps with Multi-Factor Authentication
The tutorial presents a Flutter app that requires multi-factor authentication before users can view its content, using email and password login followed by authenticator-app verification. It uses Supabase for authentication, supabase_flutter for client integration, go_router for routes and redirects, and flutter_svg to display a QR code for authenticator enrollment. During signup, users confirm their email through a deep link, enroll MFA, and then verify a code; login applies a similar second step. iOS and Android deep-link configuration directs the confirmation callback to the enrollment route, while routing checks the session and authenticator assurance level to send users to registration, enrollment, or verification as appropriate. The stated outcome is that only users who have signed in via MFA can access the home page, while optional MFA is identified as a possible future variation.
Supporting Passkeys in Shop's Authentication Flows
Shop Pay and the Shop app began deploying passkeys in December 2022 across web and native app authentication, initially as an additional method for existing users and as a replacement for email and SMS verification. Passkeys use public-key cryptography: the private key remains on the device, while the service stores a public key, with platform or roaming authenticators providing options such as biometrics or hardware keys. Built on Ruby on Rails, Shop used webauthn-ruby to store a server challenge during registration, verify the allowed domain and challenge, and save the credential identifier; login looks up that identifier and verifies authentication while updating the sign count. The team also integrated passkeys into an iframe-capable login component for use across Shopify interactions, including merchant storefronts. Domain scoping, authenticator settings, challenge handling, Conditional UI, and cross-device interoperability are identified as important implementation considerations.
Geo Queries with PostGIS in Ionic Angular
This tutorial shows how to build an Ionic Angular cross-platform app that stores and queries store locations with Supabase and PostGIS. It enables PostGIS, defines a stores table with a geography(POINT) location, adds a GiST spatial index, creates storage policies, and seeds example coordinates. SQL functions named nearby_stores and stores_in_view calculate distances or select stores inside a coordinate box, while Ionic uses Capacitor Google Maps and geolocation to display markers and query nearby data. The app also uploads store images to Supabase Storage, retrieves them with a 300-pixel contain transformation, and opens store details in an Ionic bottom-sheet modal after marker selection. The completed code is provided on GitHub and requires project and Google Maps credentials plus the included SQL.
Catching Anomalies Early in Mobile App Releases
Nextdoor deploys weekly mobile updates across iOS and Android using phased rollouts starting at 1% adoption to minimize blast radius. Standard aggregate observability cannot reliably detect early regressions because early adopters skew significantly more active than average users, obscuring silent drops in overall metric noise. To overcome this selection bias, Nextdoor built App Release Anomaly Detection using difference-in-differences causal inference. The methodology verifies pre-adoption trends with standard deviation bounds and fits a linear regression model to estimate the effect against an unobserved counterfactual. During a rollout of iOS version v1.234.5, this model identified a statistically significant app session decline at 1% adoption, isolating the regression 10 days earlier than week-over-week metrics.
Building Obsidian, Tinder’s Design System
As Tinder scaled over a decade, maintaining visual consistency across its client applications became unsustainable and increased engineering overhead. To address this, the UI Platform team developed Obsidian, a unified design system combining design tokens, reusable components, and documentation. Designers define base and context tokens in Figma using the Tokens Studio plugin, which are then transformed by Style Dictionary into native artifacts for iOS, Android, and Web. Web developers integrate these tokens using Atomizer to generate static stylesheets, while a Zeroheight documentation portal and a custom token lookup tool assist legacy migrations. The ongoing migration has streamlined collaboration between designers and engineers, resolved styling ambiguities, and improved color contrast accessibility across platforms.
Migrating our Largest Mobile App to React Native
Shopify’s largest mobile app, Shopify Mobile, had 300 screens per platform and more than six years of development, making a full rewrite impractical because it could take at least three years and halt feature work. The team first adopted React Native incrementally, but migration was projected to take four to five years while requiring three design-system implementations, three architectures, and costly native interoperability. It then switched to “Iterative Porting”: engineers were trained through the five-milestone RN Accelerator, surfaces were inventoried and prioritized with a RICE-based score, and eligible features were migrated behind flags, tested, monitored for two weeks, then completed by removing the native version. The effort also introduced Native Routes, modal deeplink handling on iOS, and component-level Safe Area fixes; with root screens ported and infrastructure in place, the team reports that ports are accelerating, although substantial work remains.
Flutter Authorization with RLS
This tutorial extends a Flutter real-time chat app by adding authorization and one-to-one conversations backed by Supabase. It introduces a rooms page for starting conversations and listing existing rooms, while flutter_bloc coordinates profile and message data across the rooms and chats pages. The database changes add rooms and room_participants tables, connect messages to rooms, expose create_new_room for reusing or creating a two-user room, and register deep links for email confirmation on iOS and Android. SQL RLS policies then restrict room, participant, and message reads to participants and require message inserts to use the caller's profile ID, producing a real-time chat app with authentication and authorization.
Lessons From Building iOS Widgets
Shopify’s widget team describes a third-generation redesign for iOS and Android after the original iOS widgets offered only two metrics and consumed substantial space. The widgets target merchants who need fresh shop analytics, using native SwiftUI on iOS because WidgetKit extensions have memory constraints, serialize SwiftUI view hierarchies to disk, and lacked official React Native support. Independent widget-side fetching uses shared session-management code and tokens; repeated update callbacks caused duplicate network requests and token-refresh races, so the team introduced a short-lived, widget-specific cache. Replacing existing widgets also exposed migration limits: changing widget kind identifiers could blank or remove installed widgets, leading Shopify to deprecate old widgets while releasing new ones and guide merchants through the transition. The team planned further customization and integration with iOS 16 features, including watch and lock-screen complications and live activities.
Lessons From Building Android Widgets
Shopify revisited its Android widgets alongside an iOS widget effort, aiming to give merchants faster access to frequently changing business metrics. The team chose native Android development because React Native lacked official RemoteViews support, while widget configuration data was persisted with shared preferences and used to build requests. Because Android could invoke onUpdate() multiple times per cycle, they added a one-minute, short-lived cache keyed by widgetID and mindful of configuration such as locale. This reduced redundant network calls, system load, and incorrect analytics, while the widget rollout also exposed migration limitations between old fixed-size widgets and new space-responsive ones, leading Shopify to deprecate the old widgets rather than transform them.
Instant Performance Upgrade: From FlatList to FlashList
Shopify’s React Native Foundations team created FlashList as a faster, easier alternative to React Native’s FlatList, targeting frame drops, blank cells, and high memory use across a wide range of devices. FlatList creates new views during updates, while FlashList recycles already-allocated cells and moves some layout operations to native, using a 250-pixel default buffer to reduce memory footprint and load times. Its API is nearly the same as FlatList, so an existing list can be swapped by changing the component name and optionally adding estimatedItemSize, with features such as type-specific recycling, flexible column spans, and FPS and blank-cell metrics. Extensive Android testing found performance of 60 FPS or greater even on low-end devices, and Shopify Mobile uses FlashList as its default while Shop moved search to it.
Supabase Flutter SDK 1.0 Developer Preview
Supabase released the Developer Preview of version 1.0 for its Flutter SDK, prioritizing improvements to developer experience across Dart applications. The new version eliminates the need for boilerplate state classes, automating authentication state persistence and deep link processing directly after initialization. To better align with Dart conventions, the SDK now throws exceptions across auth, storage, and Postgrest instead of returning error objects, while also deprecating the .execute() method for database queries. Switching to the app_links library expands deep linking support to macOS and Windows alongside existing mobile and web platforms. Supabase also introduced a companion Auth UI library for prebuilt authentication interfaces and announced plans to integrate the Multiplayer Realtime engine in the stable release.
Flutter Tutorial: building a Flutter chat app
Developers can construct cross-platform real-time chat applications for iOS, Android, and web by pairing Flutter with Supabase. The architecture relies on Supabase to manage authentication and provide direct SDK access to a Postgres database without requiring custom backend server code. The database schema defines profiles with regex validation constraints and a messages table configured for live subscriptions through Postgres publication settings. Flutter clients capture user input, insert new records into the messages table, handle database exceptions, and format chat bubbles with dynamic timestamps. While this initial setup implements user registration and message broadcasting in a shared room, securing chat rooms requires subsequent row-level security configuration.
React Native Skia—For Us, For You, and For Fun
React Native Skia brings Skia’s cross-platform 2D drawing primitives to React Native, with the stated goals of improving its limited graphical capabilities and aligning designers and developers around capabilities comparable to Figma. The integration uses React Native’s JavaScript Interface (JSI), enabling direct JavaScript-to-native communication through C++ rather than asynchronous messages, and exposes an API described as virtually 100% compatible with Flutter’s. On top of the imperative API, a declarative layer uses the React Reconciler to diff internal representation states and send changes to the Skia engine, supporting composable drawings and declarative optimizations. The library includes image filters, shaders, SVG, path operations, vertices, text layouts, mesh gradients, shadows, backdrop blur, and animations, with a direct connector to Reanimated 2; the authors expect it to address a major React Native pain point and describe the work as just beginning.
How telematics helps Grab to improve safety
Grab developed an in-house telematics engine to monitor driver-partner habits, detect crashes, and improve ride safety beyond passenger feedback. The mobile telematics SDK collects accelerometer, gyroscope, and GPS readings, running on-device processing for immediate accident detection while batching ride data for post-trip safety reports. Because triaxial sensor sampling rates vary independently across diverse devices, the SDK synchronizes data through interpolation to a uniform time grid followed by decimation to an output data rate. Telematics signals are transformed to the frequency domain using Fourier Transform for local compression before backend upload. Grab also combines telemetry with spatial data to identify dangerous road zones and plans to expand on-device event detection across all platform verticals.
Remote rendering: Shopify’s take on extensible UI
Shopify describes a UI extension architecture designed to give third-party code consistent, accessible, cross-platform experiences without allowing it to compromise the host application. Its remote-rendering approach separates UI definition from rendering, with extensions communicating with hosts through MessageChannel-based message passing; hosts are implemented in JavaScript, Kotlin, and Swift. The open-source remote-ui library supplies RPC for passing callbacks across postMessage, automatic memory management, a DOM-like RemoteRoot that serializes updates as JSON, and receivers that map remote components to DOM or React components. A sandbox isolates untrusted extension code and controls exposed APIs across web workers, Android web views, and iOS JsCore. The system powers product-subscription and post-purchase extensions, while a DOM-based version began releasing in July 2025.
Perspectives on React Native from Three Shopify Developers
Three Shopify developers—web developer AJ Robidas, Android developer Michelle Fernandez, and iOS developer Ash Furrow—describe how React Native changes mobile development for people from different backgrounds. They say its React-based model lets web developers build for iOS and Android, helps native developers create interfaces faster and reach a wider audience, and supports collaboration across web, Android, and iOS teams. The developers discuss surprises including React Native’s small set of building blocks, fast UI feedback, native bridge modules, existing SDK integration, and apps that can be difficult to distinguish from Swift or Objective-C software. They also identify challenges such as mobile-specific performance concerns across the RN Bridge, the Metro and Node ecosystem, and the large dependency stack. At Shopify, Visual Studio Code, command-line tooling, internal foundations, workshops, and cross-disciplinary teams support adoption.
Reflecting on the Five Years of Bug Bounty at Grab
Grab launched a private bug bounty programme on HackerOne before opening it publicly in 2017 to complement internal product security efforts. Prior to going public, the team conducted security sweeps, established policies, and expanded the testing scope to prepare for an influx of reports. Operationally, the team opted to pay full bounties immediately upon report triage rather than waiting for vulnerability resolution to incentivize security researchers. Noise reduction was handled using HackerOne Triage, Human-Augmented Signal, and by blocking automated scanning networks targeting Grab's infrastructure. In addition, rotating security engineers weekly and integrating HackerOne APIs with PagerDuty ensured fast initial response times.
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