How to Build a Backend for WatchOS?

introduction in this tutorial, you’ll discover how to build a backend for watchos apps using back4app whether you’re creating a watchkit extension for your iphone app or designing a standalone apple watch experience, back4app simplifies your work by providing essential tools you’ll integrate features like a secure database, cloud code functions, real time queries (live queries), and user authentication—all without managing your own servers you’ll also see how back4app’s quick startup routine and easy to use environment allow you to focus on your watchos apps functionality, rather than setting up servers along the way, you’ll learn to handle tasks such as scheduling jobs, setting up webhooks, and configuring push notifications by the end, you’ll have a solid foundation to extend your watch apps or ios applications for production level needs, all while delivering seamless data synchronization (over an internet connection ) between the watchkit app and your backend prerequisites a back4app account and a new back4app project getting started with back4app https //www back4app com/docs/get started/new parse app if you do not have an account, you can create one for free follow the guide above to get your project ready a watchos/xcode development environment you should have xcode installed with the watchos sdk you can run and build your watchkit extension on either a real apple watch or a simulator parse swift sdk use swift package manager https //github com/netreconlab/parse swift to install and configure the sdk for your watchos or combined ios apps familiarity with swift, xcode, and apple’s development ecosystem apple developer documentation https //developer apple com/documentation/ if you’re new to apple platforms, spend some time exploring the watchos and ios docs before starting make sure you meet these prerequisites before you begin having your back4app project set up and your local watchos environment ready will help you follow along smoothly step 1 – creating a new project on back4app and connecting why you need a back4app project a new back4app project is essential for storing all data and running cloud code for your watchos apps this serves as the foundation of your backend create your project log in to back4app click “new app” in the dashboard name your app (e g , “watchos backend tutorial”) install parse swift sdk add the parse swift dependency in your package swift or by using file → swift packages → add package dependency in xcode provide the url dependencies \[ package(url "https //github com/netreconlab/parse swift git", from "5 0 0") ] initialize parse in your watchos or shared code in your watchkit app’s startup code or in a shared file accessible by both your watchos and iphone app , initialize parse @main struct mywatchapp app { init() { task { do { try await parseswift initialize( applicationid "your app id", clientkey "your client key", serverurl url(string "https //parseapi back4app com")! ) } catch { print("error initializing parse \\(error)") } } } var body some scene { windowgroup { contentview() } } } at this point, your watchos app can communicate with the back4app backend whether it's an independent apple watch app or a watchkit extension paired with an iphone app , all backend data flows through the parse swift sdk step 2 – setting up the database 1\ creating a data model back4app uses parse server’s schema on write feature you can define tables (classes) in the back4app database section or let them be created automatically when objects are first saved for instance, if your watch apps track health data, you might have a “healthmetrics” class with fields like heartrate, steps, or workouttype 2\ creating a data model using the ai agent back4app’s ai agent lets you describe your schema in plain language open the ai agent in your app dashboard provide details like “please set up a watch metrics class with fields dailysteps (number), heartrate (number) ” the ai will create the schema for you automatically 3\ reading and writing data using the sdk below is an example of saving and querying data from a watchos app let’s suppose we have a healthmetrics struct import parseswift struct healthmetrics parseobject { var objectid string? var createdat date? var updatedat date? var acl parseacl? var originaldata data? var dailysteps int? var heartrate int? } // saving data func savemetrics(steps int, heart int) async { var metrics = healthmetrics() metrics dailysteps = steps metrics heartrate = heart do { let saved = try await metrics save() print("saved metrics \\(saved)") } catch { print("error saving \\(error)") } } // querying data func fetchlatestmetrics() async { let query = healthmetrics query() do { let results = try await query find() print("fetched \\(results count) items") } catch { print("error fetching \\(error)") } } 4\ reading and writing data using rest api if needed, your watchos or ios apps can also send rest requests curl x post \\ h "x parse application id your app id" \\ h "x parse rest api key your rest api key" \\ h "content type application/json" \\ d '{"dailysteps" 8000, "heartrate" 75}' \\ https //parseapi back4app com/classes/healthmetrics 5\ reading and writing data using graphql back4app also provides a graphql endpoint for instance mutation { createhealthmetrics(input { fields { dailysteps 7500 heartrate 70 } }) { healthmetrics { objectid dailysteps heartrate } } } 6\ working with live queries (optional) if you need real time data updates on your apple watch , enable live queries turn on live queries under server settings in back4app configure the live query url in your watchos code parselivequery configure(url url(string "wss\ //your subdomain b4a io")!) then subscribe to changes func subscribemetricsupdates() async throws { let subscription = healthmetrics query() subscribe() for try await event in subscription { switch event { case created(let newdata) print("new data \\(newdata)") case updated(let updateddata) print("updated \\(updateddata)") default break } } } step 3 – applying security with acls and clps 1\ brief overview back4app allows access control lists (acls) and class level permissions (clps) to secure your database for example, you might restrict certain metrics to the user who generated them or allow read access only to authenticated accounts 2\ step by step setup class level permissions go to database → class → security to define defaults (e g , read only for all, write for owners) acls in code you can add acls to each object in your watchkit or shared code for instance if let user = user current { var acl = parseacl() acl setreadaccess(user user, value true) acl setwriteaccess(user user, value true) var metrics = healthmetrics() metrics acl = acl } this ensures only the logged in user can view or modify the healthmetrics objects they create step 4 – writing cloud code functions 1\ why cloud code cloud code helps you run complex or confidential operations server side, such as data validation, external api calls, or logging this setup is useful for minimizing watchos device workload and preserving battery life on the apple watch 2\ example function in your main js parse cloud define('processmetrics', async (request) => { const { dailysteps, heartrate } = request params; if (!dailysteps || !heartrate) { throw 'missing parameters '; } // example simple calculation return dailysteps heartrate; }); 3\ deployment use the back4app cli https //www back4app com/docs/local development/parse cli to deploy b4a deploy 4\ installing npm modules if you need external libraries in your cloud code add dependencies in package json (within your cloud code folder) use require('your lib') in main js step 5 – configuring authentication 1\ enable user authentication by default, the user class is ready in back4app make sure “enable class level permissions” is set correctly for user objects 2\ code samples in parse swift, you might sign up a user from your watchos code struct user parseuser { var objectid string? var createdat date? var updatedat date? var acl parseacl? var originaldata data? var username string? var email string? var emailverified bool? var password string? var authdata \[string \[string string]?]? } func signupnewuser(name string, pass string, mail string) async { var newuser = user() newuser username = name newuser password = pass newuser email = mail do { let signedup = try await newuser signup() print("sign up successful \\(signedup)") } catch { print("error signing up \\(error)") } } 3\ social login if you plan on integrating apple, google, or facebook login in your watchos or iphone app, you can do so with the relevant parse swift social login features see back4app docs https //www back4app com/docs/platform/sign in with apple for details step 6 – handling file storage 1\ setting up file storage if your watch apps need to upload images, logs, or small data files, you can rely on parsefile func uploadfile(data data, filename string) async { let file = parsefile(name filename, data data) do { let savedfile = try await file save() print("uploaded file \\(savedfile url ?? "")") } catch { print("error uploading file \\(error)") } } 2\ example you might store workout images or daily progress snapshots let snapshotdata = // some image data from watch screenshot task { await uploadfile(data snapshotdata, filename "workout jpg") } 3\ security considerations review your file acls by default, file urls are accessible if someone obtains the direct link you can secure or control file access via your parse server’s file configuration step 7 – email verification and password reset 1\ overview apple watch users may not always manage logins directly on the watch, but enabling email verification helps keep their data secure 2\ back4app dashboard configuration go to app settings → email turn on email verification customize templates as needed 3\ code/implementation for password resets do { try await user requestpasswordreset(email "example\@domain com") } catch { print("error requesting password reset \\(error)") } step 8 – scheduling tasks with cloud jobs 1\ what cloud jobs do cloud jobs let you automate background tasks like rotating old data or generating usage reports for your watchos analytics 2\ example in main js parse cloud job('cleanupmetrics', async (request) => { const query = new parse query('healthmetrics'); // for example, remove records older than 7 days const now = new date(); const cutoff = new date(now 7 24 60 60 1000); query lessthan('createdat', cutoff); const oldmetrics = await query find({ usemasterkey true }); await parse object destroyall(oldmetrics, { usemasterkey true }); return `deleted ${oldmetrics length} old records `; }); deploy your code go to app settings → server settings → background jobs and schedule it daily step 9 – integrating webhooks 1\ definition webhooks notify external services when certain events happen in your app for instance, you might want to ping a slack channel every time a new metric is recorded 2\ configuration in the back4app dashboard, go to more → webhooks add a webhook with an endpoint (like a slack url) choose the event (e g , “new record in healthmetrics”) 3\ example whenever a user adds a new dailysteps entry, your slack channel is notified you can also define more complex logic in cloud code to send custom payloads to your external services step 10 – exploring the back4app admin panel 1\ where to find it the admin panel is accessible via your back4app console under more → admin app enable it and create an admin user for web based data management if you need a straightforward interface for non technical stakeholders 2\ features view and edit data manage logs and cloud jobs track analytics or push notifications this is an easy way to collaborate on data without needing direct database or code access conclusion throughout this guide, you learned how to build a backend for watchos using back4app’s powerful features you set up a secure database schema, wrote cloud code, handled real time queries, and implemented user authentication now your watchkit app can store and sync data with minimal hassle next steps polish your watch apps by integrating advanced cloud functions for personalized notifications or data transformations explore additional ios applications functionalities, like background sync and caching strategies for your apple watch read the official back4app docs https //www back4app com/docs/ for more on advanced security, analytics, and performance optimize for the app store to distribute your watchos extension or standalone watch app by expanding your backend, you can deliver robust watchos apps that work seamlessly even with limited internet connection keep building and enjoy the power of back4app for your apple watch experiences!