Supabase Mobile Proxies: Auth, Realtime and Edge From a US Phone
A Supabase project is a Postgres database, Auth, Storage, Realtime and Edge Functions behind one API, and your app talks to it from wherever the user is. For US users that is a phone on a carrier network. Auth providers and OTP flows, Realtime WebSockets and Edge Function cold starts all behave differently on mobile latency and from a mobile address than from your laptop. A Mobile Proxies US line gives the US mobile client position: one carrier SIM in one metro, HTTP(S), SOCKS5 and VLESS endpoints, exit IP and rotation in an API.
What changes when the client is on a US carrier
Auth: phone sign-in and OTP via your SMS provider, OAuth redirects through providers that score the source address, captcha challenges on signup. Realtime: WebSocket reconnects under cellular handovers and carrier NAT timeouts. Storage: large uploads and signed-URL downloads at mobile bandwidth. Edge Functions: latency from a US mobile address to your chosen region, including cold starts.
Your own server-side jobs and migrations are unaffected and stay on your usual addresses. The line is only for the client side.
Testing Auth flows from the line
Run your web app in a browser profile behind the line's HTTP endpoint, or the mobile build in an emulator behind SOCKS5. Sign up with your own test accounts and numbers. Observe captcha frequency, OAuth provider behaviour and OTP delivery timing as a US mobile user experiences them. A hosting address inflates captcha frequency; the carrier address shows the real rate.
Log exit IP and carrier from the API per attempt. Auth providers occasionally treat carrier ranges differently; the log makes that visible.
Realtime and Edge Functions under mobile conditions
Subscribe to a Realtime channel through the line and leave it running. Then rotate the line on purpose: the modem re-attaches, the socket drops, and your reconnection and replay logic is exercised against a genuine carrier event rather than a simulated one. Measure how long presence and subscriptions take to recover.
For Edge Functions, time calls from the line to each region you consider deploying to. A US mobile client's latency to a US region versus elsewhere is a deployment decision, and this is how to measure it with real numbers.
Per-IP limits under carrier NAT
Supabase Auth applies some of its rate limits per IP, and a carrier address is shared by many subscribers behind NAT. On a real network, several of your users can arrive from one address. Reproduce that from the line: run your normal sign-in and token-refresh traffic from several test accounts through one exit IP and watch for the limit responses, then decide whether your project's settings suit a mobile audience.
If your Edge Functions log the client address from the forwarded header, compare it with ip from GET /proxy/status to confirm the function sees the carrier address and not a hop in front of it. Then subscribe to proxy.ip_changed: its timestamp marks exactly when a Realtime client should begin reconnecting, which gives you a true start point for measuring recovery. Record how many accounts shared the address during each run, because that count is what the limit reacts to.
Rotation and terms
Rotate deliberately: between test runs for a fresh address, or during a Realtime test to simulate a network change. Confirm the new exit IP through an echo request before relying on it.
Use your own Supabase project, your own test accounts and your own SMS and OAuth credentials within Supabase's and each provider's terms. Data on the line is not metered; a fair-use rule concerns only lines moving 60 GB in a UTC day repeatedly.
Setting up a Supabase proxy on Mobile Proxies US
- Buy a line in the US metro closest to your users, or one per metro you care about.
- Read endpoints from the API; configure a browser profile (HTTP) or emulator (SOCKS5) for your app.
- Verify the exit IP is a carrier address and matches ip from GET /proxy/status.
- Run Auth, Storage, Realtime and Edge Function checks; log exit IP, carrier and timings per case.
- Rotate during a Realtime session to test reconnects; rotate between runs for fresh addresses.
Supabase proxy questions
Should my server-side Supabase calls go through the line?
No. Server calls stay where they are. The line represents the end user's phone.
How do I simulate a network change for Realtime?
Rotate the line by API mid-session. The modem re-attaches and the socket drops, as on a real handover.
Can I measure Edge Function latency by region?
Yes. Time calls from the line to functions deployed in each candidate region. The line sits on a US carrier network, so the numbers reflect a US mobile user.