Feature spec
IntermediateCategory
maps-location
Build with AI
3–6 hours with Lovable or FlutterFlow
Custom build
3–5 days custom dev
Running cost
$0–$5/mo up to 1K users
Works on
Everything it takes to ship Geolocation — parts, prompts, and real costs.
Geolocation needs a permission request layer, a location provider (Geolocation API on web, geolocator package in Flutter), and a Supabase table with PostGIS for storing and querying coordinates. With Lovable or FlutterFlow you can ship a working implementation in 3–6 hours for $0–$5/month up to 1,000 users. The only costs that appear are reverse geocoding (converting coordinates to addresses) and Supabase Pro beyond the free tier.
What Geolocation Actually Is in an App Context
Geolocation gives your app the user's physical coordinates — latitude, longitude, and accuracy radius. On web it calls navigator.geolocation.getCurrentPosition(); on Flutter it uses the geolocator package. Those coordinates then power everything else: centering a map on the user, filtering nearby listings, checking in at a location, or querying which delivery zone someone is in. The positioning itself is a solved, free problem. The product decisions that matter are accuracy versus battery life, what to do when the user says no, and how to store coordinates so PostGIS can answer proximity queries like "find listings within 5km" without a full table scan.
What users consider table stakes in 2026
- Permission is requested before any location read, with a clear explanation of why the app needs it
- A spinner or 'Acquiring location…' state is shown during the 2–60 second GPS cold-start window
- When permission is denied, a manual city or address input fallback appears immediately — no blank screen
- The last known position is cached so the app can show something useful on relaunch before a fresh fix arrives
- Accuracy radius is displayed so users know whether they're seeing a precise GPS fix or a rough cell-tower estimate
- Battery-friendly low-accuracy mode is used for non-precision features like region detection or content filtering
Anatomy of the Geolocation Feature
Five components — two of which AI tools generate reliably, two that commonly break, and one (the reverse geocoder) that requires an Edge Function to hide the API key.
Permission request layer
UIPrompts the user for location permission before any position read. On web this is the browser's native permission dialog triggered by navigator.geolocation.getCurrentPosition(). On Flutter, the geolocator package combined with permission_handler (pub.dev) handles the request and auto-wires AndroidManifest.xml and Info.plist entries.
Note: Never request location on page load without context. Trigger the prompt from a clear user action (tap 'Find nearby', tap 'Check in') to maximise acceptance rates. On iOS, the permission prompt must include a usage description string or Apple rejects the app build.
Location provider
BackendReads the actual coordinates from GPS, Wi-Fi triangulation, and cell towers. On web: navigator.geolocation.getCurrentPosition({ enableHighAccuracy: true, timeout: 10000 }). On Flutter: geolocator.getCurrentPosition(desiredAccuracy: LocationAccuracy.high) for precise features, LocationAccuracy.low for background or battery-sensitive use cases.
Note: High accuracy draws more battery. For features like region detection or content personalisation, LocationAccuracy.low (cell + Wi-Fi only) is adequate and significantly kinder on battery life.
Position store
DataA Supabase table user_locations with columns user_id, lat, lng, accuracy, and recorded_at. Storing coordinates enables history screens, proximity queries via PostGIS ST_DWithin, and audit trails for deliveries or field workers.
Note: PostGIS extension must be explicitly enabled before adding geography columns or running ST_DWithin queries. Run CREATE EXTENSION IF NOT EXISTS postgis; in the Supabase SQL editor before applying the schema.
Reverse geocoder
ServiceConverts raw lat/lng coordinates into a human-readable address string ('123 Main St, Austin, TX'). Options: Google Maps Geocoding API ($5 per 1,000 requests after $200/mo free credit) or Mapbox Geocoding API (100,000 requests/mo free, then $0.75 per 1,000 approx). Always called via a Supabase Edge Function — never directly from the client — to keep the API key secret.
Note: Cache geocoding results in your database. Most apps re-geocode the same addresses repeatedly; one cached lookup per location saves hundreds of API calls.
Permission state manager
UITracks the three possible states: granted, denied, and undetermined (not yet asked). Renders the appropriate UI for each: the map or nearby content for granted, a manual city/address input picker for denied, and a permission request button for undetermined. On Flutter, the permission_handler package exposes a PermissionStatus enum covering all three states.
Note: The manual fallback for the denied state is skipped by most AI-generated builds. Always include it explicitly in your prompt — a blank screen when geolocation is denied is one of the most common first-build failures.
The data model
One table captures location history with full PostGIS support for proximity queries. Run this in the Supabase SQL editor after enabling the PostGIS extension:
1-- Enable PostGIS (run once per project)2CREATE EXTENSION IF NOT EXISTS postgis;34create table public.user_locations (5 id uuid primary key default gen_random_uuid(),6 user_id uuid references auth.users(id) on delete cascade not null,7 lat float8 not null,8 lng float8 not null,9 accuracy float4,10 source text default 'gps',11 recorded_at timestamptz not null default now()12);1314alter table public.user_locations enable row level security;1516create policy "Users can view own locations"17 on public.user_locations for select18 using (auth.uid() = user_id);1920create policy "Users can insert own locations"21 on public.user_locations for insert22 with check (auth.uid() = user_id);2324create index user_locations_user_idx25 on public.user_locations (user_id, recorded_at desc);2627create index user_locations_geo_idx28 on public.user_locations using gist (29 st_point(lng, lat)::geography30 );Heads up: The GiST index on the geography column is what makes ST_DWithin proximity queries fast at scale. Without it, a 'find users within 5km' query does a full table scan. The source column lets you distinguish GPS fixes from manual city picker entries — useful for analytics on accuracy quality.
Build it — pick your path
Each tool fits this feature differently. Switch tabs to compare fit, time, the exact steps, and a copy-paste prompt.
FlutterFlow's geolocator integration is first-class — the Action editor wires permission requests, accuracy settings, and AndroidManifest/Info.plist entries automatically, making this the best path for any mobile-first geolocation feature.
Step by step
- 1In the Action editor, add a 'Request Permission' action and select Location; FlutterFlow auto-adds ACCESS_FINE_LOCATION and ACCESS_COARSE_LOCATION to AndroidManifest.xml and NSLocationWhenInUseUsageDescription to Info.plist
- 2Add a 'Get Current Location' action (wraps geolocator.getCurrentPosition) after the permission grant; store the result in a page state variable of type LatLng
- 3Wire conditional visibility: show the spinner widget while location is null, show the location display once LatLng is populated, and show the manual input widget when permission is denied (check PermissionStatus via permission_handler)
- 4Add a Supabase Insert action writing user_id (from Supabase Auth), lat, lng, accuracy, and recorded_at to the user_locations table
- 5Test on a physical device via the FlutterFlow mobile app — the web preview does not access native GPS
Where this path bites
- Background location tracking (rides, deliveries) requires a custom code block with Workmanager; FlutterFlow's built-in action reads location once on tap
- PostGIS ST_DWithin proximity queries require a Supabase custom RPC function called via the REST API; FlutterFlow cannot build the SQL query visually
- App Store submission requires a specific NSLocationWhenInUseUsageDescription string — 'we need location' phrasing causes rejection; be specific
Third-party services you'll need
The location read itself is free. Costs appear only if you convert coordinates to readable addresses (reverse geocoding) or store and query them at scale in Supabase.
| Service | What it does | Free tier | Paid from |
|---|---|---|---|
| Google Maps Geocoding API | Convert lat/lng to human-readable address string | $200/mo credit (covers ~40K geocoding requests) | $5 per 1,000 requests after credit |
| Mapbox Geocoding API | Reverse geocoding alternative with generous free tier | 100,000 requests/mo free | $0.75 per 1,000 requests after free tier (approx) |
| Supabase + PostGIS | Store user_locations table, run proximity queries, enforce RLS | Free tier: 500MB DB, 2 projects | Pro $25/mo (8GB DB, unlimited projects) |
Swipe the table sideways to see pricing.
What it costs to run
Drag through the tiers to see how your monthly bill scales with users — no surprises later.
Estimated monthly running cost
Supabase free tier easily handles location rows at this scale. Mapbox free geocoding covers all reverse geocoding calls. Location read itself is free.
Estimates use verified 2026 pricing and assume typical usage per user. Your real bill depends on activity, storage, and third-party plans.
What breaks when AI tools build this
The failures people actually hit on their first build — the symptom, why it happens, and the exact fix.
Lovable preview returns no location — silently
Symptom: The browser security policy denies geolocation to cross-origin iframes. The Lovable preview pane is embedded in an iframe, so navigator.geolocation.getCurrentPosition() executes but the success callback never fires — no error, no result, no indication anything is wrong.
Fix: Always test geolocation on the published production URL, not the preview. In Lovable, click Publish and open the live URL on your phone. Add a temporary lat/lng override constant (e.g. lat: 40.7128, lng: -74.006) during development so you can verify the rest of the feature before testing the actual GPS read.
Permission denied shows a blank screen with no fallback
Symptom: AI-generated code typically checks navigator.permissions or the error code in the getCurrentPosition error callback, but renders nothing when the user denies. The user is left staring at an empty div with no way to proceed.
Fix: Explicitly prompt for a manual city/address input fallback that renders when permissionDenied state is true. The component should have four states in code: idle, loading, success, and denied — each with distinct UI. Never leave denied as a blank render.
FlutterFlow crashes on Android 12+ without COARSE location permission
Symptom: The geolocator package requires both ACCESS_FINE_LOCATION and ACCESS_COARSE_LOCATION in AndroidManifest.xml on Android 12+. When only FINE is declared, the permission dialog sometimes fails silently and the app crashes on position read.
Fix: In FlutterFlow, go to Settings → App Permissions and explicitly enable both Fine Location and Coarse Location. FlutterFlow sometimes omits COARSE when only FINE is requested in the Action editor. Verify both appear in the generated AndroidManifest.xml before building a release APK.
Supabase INSERT exposes all user locations without RLS
Symptom: AI-generated code often creates the user_locations table and inserts rows correctly but skips enabling Row Level Security. Anyone with the anon key can then run SELECT * FROM user_locations and see every user's coordinates — a serious privacy violation.
Fix: Enable RLS on user_locations immediately after creating the table. Add two policies: SELECT USING (auth.uid() = user_id) and INSERT WITH CHECK (auth.uid() = user_id). Test by querying the table with a different user's session to confirm rows are invisible.
GPS cold start takes 30–60 seconds with no feedback
Symptom: On the first position read after a device restart, GPS needs time to acquire satellite lock. navigator.geolocation defaults to returning a cached position that may be hours old and kilometres off. geolocator on Flutter returns a cached fix immediately with low accuracy. If the UI transitions to 'success' on the first result without checking accuracy, it shows the wrong location.
Fix: Always check the accuracy value on the first position result. Set a threshold (e.g. reject readings with accuracy > 100m) and continue showing the 'acquiring' state with a progress message until a sufficiently accurate fix arrives. Set a forceAndroidLocationManager: false flag in Flutter and pass a timeout so the app doesn't wait indefinitely.
Best practices
Request location permission from a clear user action, not on page load — explaining why before the prompt doubles acceptance rates
Cache the last known good position in Supabase and display it immediately on relaunch while a fresh fix acquires
Always build the manual city/address input fallback before shipping — denying location permission is common on mobile, especially on first launch
Use low accuracy mode (cell + Wi-Fi) for non-precision features like region detection — it responds in under a second and drains far less battery
Geocode addresses once and cache the result in your database — re-geocoding the same coordinates on every request wastes API quota and adds latency
Log accuracy values alongside coordinates — knowing whether your users are getting GPS-quality fixes or cell-tower guesses helps diagnose proximity feature failures
Never hardcode geocoding API keys in frontend code — always proxy through a Supabase Edge Function using Deno.env.get()
Enable the PostGIS GiST index before you need it — retrofitting it on a table with millions of rows locks the table and causes downtime
When You Need Custom Development for Geolocation
AI tools handle single-read location features well. These scenarios require a custom build:
- Background location tracking for rides, deliveries, or field workers — requires Workmanager on Android, background mode entitlement on iOS, and App Store justification that adds weeks to review
- Geofencing: triggering notifications or workflows when users enter or exit a defined zone — needs flutter_geofence or native Geofencing APIs that go beyond what FlutterFlow exposes without custom code blocks
- Proximity search across millions of records at sub-50ms latency — PostGIS GiST indexing and query optimisation require hands-on PostgreSQL expertise
- Accuracy below 10 metres for sports tracking, navigation, or precision field operations — standard mobile GPS APIs plateau here; external GNSS hardware integration is needed
RapidDev builds these features for production
Real auth, database, and payments — fixed price, delivered in weeks. You own 100% of the code.
Frequently asked questions
Does geolocation work in Lovable preview?
No. The Lovable preview pane runs inside a cross-origin iframe, which browsers block from accessing geolocation for security reasons. navigator.geolocation.getCurrentPosition() executes silently with no result and no error. Publish your app and test on the live HTTPS URL from a real phone — geolocation works correctly there.
How do I store user locations in Supabase?
Create a user_locations table with columns for user_id (FK to auth.users), lat (float8), lng (float8), accuracy (float4), and recorded_at (timestamptz). Enable Row Level Security and add a policy so users can only read and insert their own rows. For proximity queries, enable the PostGIS extension and add a GiST index on the geography column — this makes ST_DWithin queries fast even across millions of rows.
What happens when a user denies location permission?
Your app should immediately show a manual city or address input field — never a blank screen. Store the user's manually entered location the same way you'd store a GPS result, just with a different source value. On web, after a user denies, the browser often blocks future permission prompts from the same origin, so the fallback is the only path back.
How accurate is web geolocation compared to native mobile?
Web geolocation (navigator.geolocation) uses whatever signals the browser can access — GPS if the device has it and permission is granted, then Wi-Fi positioning, then cell tower triangulation. In practice, a phone browser with GPS on achieves 5–15m accuracy, similar to native. The key difference is that native apps (via geolocator in Flutter) can access background location and continuous updates, while web can only read location when the page is in the foreground.
How do I convert coordinates to an address?
Use a reverse geocoding API: Mapbox Geocoding API is the best free option (100K requests/mo free), and Google Maps Geocoding API offers $200/mo credit then $5/1K requests. Always call the geocoding API from a server-side function (Supabase Edge Function or Next.js API route) rather than directly from the client — your API key would be exposed in browser network requests otherwise. Cache every result in your database to avoid repeat calls.
Is location data stored securely?
Only if you enable Supabase Row Level Security. Without RLS, anyone with your anon key can query every user's coordinates. Enable RLS on user_locations and set a policy of USING (auth.uid() = user_id) — this ensures each user can only access their own location history. Never store precise GPS trails without user consent disclosure in your privacy policy.
Can I track location in the background on mobile?
Yes, but it requires custom development beyond what AI tools generate. On Flutter, Workmanager handles background Dart isolates; on iOS, you need the Location background mode capability and a convincing App Store justification. Background location is the feature most likely to trigger App Store review requests or rejection — budget an extra 2–4 weeks for that process.
How much does reverse geocoding cost at scale?
Mapbox gives 100,000 geocoding requests per month free — enough for roughly 3,000 daily active users who each trigger one geocode per session. Beyond that, $0.75 per 1,000 requests (approx). The way to keep costs near zero is to cache: store the geocoded address in your database the first time, and serve the cached version for all future reads of the same coordinates.
Need this feature production-ready?
RapidDev builds geolocation into real apps — auth, database, payments — at $13K–$25K.
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