Google APIs — Verification Checklist

Before connecting any Google API to real app features, verify each one independently. A problem caught here takes 2 minutes to fix. The same problem discovered halfway through building a feature takes 30 minutes to trace back to the API setup.

Work through each section in order. Do not skip ahead.

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Google Cloud Setup

These are prerequisites. If any of these are not done, the API calls will fail regardless of how correctly your code is written.

• Google Cloud project exists — you can see it in the top dropdown at console.cloud.google.com
• Billing account is attached — console.cloud.google.com → Billing → confirm a billing account is linked to the project (a payment method is required even for the free tier)
• Billing alert is set — Billing → Budgets & Alerts → a budget alert exists at $10 or similar, so you receive an email before any unexpected charge
• Maps JavaScript API is enabled — APIs & Services → Enabled APIs → "Maps JavaScript API" appears in the list
• Places API is enabled — "Places API" appears in the Enabled APIs list
• Geocoding API is enabled — "Geocoding API" appears in the Enabled APIs list
• Generative Language API is enabled — "Generative Language API" (Gemini) appears in the list

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API Key Configuration

• An API key exists — APIs & Services → Credentials → at least one API key is listed
• The Maps/Places/Geocoding key has domain restrictions set — click the key → "Application restrictions" → "HTTP referrers" → your domains are listed (e.g. localhost:* for development, your Vercel domain for production)
• The Maps key is in your .env file — your web project's .env or .env.local contains NEXT_PUBLIC_GOOGLE_MAPS_API_KEY=AIzaSy... (or VITE_GOOGLE_MAPS_API_KEY= for Vite projects)
• The Gemini key is in Supabase secrets — run npx supabase secrets list → GEMINI_API_KEY appears (do NOT put the Gemini key in .env)
• .env is in .gitignore — confirm your environment file is not tracked by git (git status should not show .env as a new or modified file)

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Maps JavaScript API

Test: a map renders in your app.

Create a test page or component with the minimal map code from the Maps API page. Open it in your browser.

• No console errors — open the browser DevTools console (F12 → Console tab). There should be no red errors. Common errors at this stage:
  • Google Maps JavaScript API error: RefererNotAllowedMapError → your domain isn't in the key's HTTP referrer restrictions — add localhost:* for development
  • Google Maps JavaScript API error: ApiNotActivatedMapError → the Maps JavaScript API isn't enabled in Cloud Console
  • Google Maps JavaScript API error: InvalidKeyMapError → the key in your .env doesn't match what's in Cloud Console
• Map renders visually — you can see the Google Maps tiles (the actual map image) in the browser
• Map is interactive — you can click and drag to pan, scroll to zoom
• A marker appears — if you added a <Marker> component, the pin is visible at the correct coordinates

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Places API (Address Autocomplete)

Test: the autocomplete shows suggestions when you type.

Add the AddressAutocomplete component from the Places & Geocoding page to a test page. Type a partial address.

• Suggestions appear after 2–3 characters — typing "Ban" should show suggestions like "Banjara Hills, Hyderabad, Telangana, India"
• Suggestions are restricted to India — you should not see results from the UK, USA, or other countries (confirms componentRestrictions: { country: 'in' } is working)
• Selecting a suggestion fires the callback — click a suggestion and confirm your onAddressSelected callback receives the { formatted, lat, lng } object (log it to the console to verify)
• Coordinates are numbers, not strings — typeof lat === 'number' should be true. If you get "17.4126" (a string in quotes) instead of 17.4126, check whether you are calling .lat() as a function (for the Autocomplete component) vs reading .lat as a property (for the mobile library)

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Geocoding API

Test: converting an address string to coordinates.

Run the geocodeAddress function from the Places & Geocoding page (or use the edge function test below) with a known address.

Quick browser test (paste into DevTools console, after the Maps SDK has loaded):

Expected output:

• Status is OK — any other status (ZERO_RESULTS, REQUEST_DENIED, OVER_QUERY_LIMIT) indicates a setup problem
• Coordinates are in the expected range for India — latitude should be between 8 and 37, longitude between 68 and 98
• Edge function geocoding works — if you have built the server-side geocoding edge function, test it with supabase functions serve locally and call it with a test address

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Gemini API

Test: the edge function returns AI-generated text.

Use supabase functions serve to run your edge function locally, then call it with test data.

Local test (run in a new terminal after npx supabase functions serve):

Expected response:

• The edge function starts without errors — supabase functions serve output should show the function loaded, not a Deno compile error
• The API call succeeds — response HTTP status is 200
• GEMINI_API_KEY is accessible in the function — if you get a TypeError: Cannot read properties of undefined on the genAI line, the secret is not set. Run npx supabase secrets set GEMINI_API_KEY=your_key_here and restart functions serve
• The response contains a bio — the returned text is coherent, professional, and relevant to the input
• The function requires authentication — call it without the Authorization header and confirm you receive a 401 response (not a 200)

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Mobile (React Native / Expo)

If you are working on the Expo mobile app:

• react-native-maps renders a map — the MapView component shows Google Maps tiles on Android
• API key is in app.json under expo.android.config.googleMaps.apiKey
• react-native-google-places-autocomplete shows suggestions — typing in the autocomplete input shows Place suggestions
• fetchDetails={true} returns coordinates — selecting a suggestion logs both the description and the geometry.location object

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Common Failure Modes (Reference)

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Before Moving On

All items above should be checked before connecting any Google API to a real feature in your app. A working API call in isolation is the proof that your setup is correct. Problems discovered at this stage are configuration problems — fast to fix. The same problems discovered while building a feature are buried under layers of component code and take much longer to find.

Once all checks pass, you are ready to use these APIs in real features.