Supabase C# Client: Fix InitializeAsync Hanging Issue

If your Supabase C# client InitializeAsync() is hanging indefinitely with no errors or exceptions—even in a try-catch—it’s typically due to mismatched credentials, network restrictions like IP bans, or the realtime auto-connect feature clashing with your setup. Double-check you’re using the correct project URL (e.g., https://yourproject.supabase.co) and anon/public key from Settings > API, not the Postgres connection string. A quick test: set AutoConnectRealtime = false in options and retry; if it works, realtime networking is the culprit.

Contents

• Supabase C# Client Connection Issues Overview
• Wrong URL or API Key: The Most Common Culprit
• Network Blocks and IP Bans
• Realtime Connection Hangs with AutoConnectRealtime
• Async Initialization Pitfalls in Services
• Debugging and Timeout Fixes
• Sources
• Conclusion

Supabase C# Client Connection Issues Overview

That silent hang on await _supabase.InitializeAsync(); drives developers nuts. No stack trace. No timeout. Just… nothing. From scouring Supabase docs and community threads, this pops up in C# more than you’d expect, often tied to how the client probes endpoints during init.

Why C# specifically? The official Supabase C# docs stress pulling SUPABASE_URL and SUPABASE_KEY from env vars, then initializing with options like AutoConnectRealtime. But if the URL points to your raw Postgres host (db.project.supabase.co:5432) instead of the API gateway, it dead-ends. Same for mixing service_role keys client-side—they’re for server-only ops.

Quick checklist before diving deeper:

• Environment vars set? Test with hardcoded values temporarily.
• IPv4 confirmed in dashboard > Connect? IPv6-only can flake.
• Proxy/firewall nuking outbound HTTPS to *.supabase.co?

Hang tight—most fixes are straightforward.

Wrong URL or API Key: The Most Common Culprit

Ever grabbed the “Host” from Connect and jammed it into the client? Big mistake. Supabase C# expects the project API URL—https://<project-ref>.supabase.co—paired with the anon key (public, from Settings > API). The Postgres string (with port 5432) is for direct DB tools like pgAdmin, not the client library.

Here’s your code tweaked for sanity:

var url = Environment.GetEnvironmentVariable("SUPABASE_URL"); // https://xyz.supabase.co
var key = Environment.GetEnvironmentVariable("SUPABASE_ANON_KEY"); // anon/public only!

var options = new SupabaseOptions
{
 AutoConnectRealtime = false // Disable first for testing
};

var supabase = new Client(url, key, options);
try 
{
 await supabase.InitializeAsync();
 Console.WriteLine("Connected!"); // Or log success
}
catch (Exception ex)
{
 Console.WriteLine($"Failed: {ex.Message}");
}

Pro tip: Log the URL/key (redact key) right before init. Mismatch? That’s 80% of cases, per Supabase troubleshooting.

Service keys tempt for power, but expose them server-side only—GitHub warns they’ll leak auth holes.

Network Blocks and IP Bans

No credentials drama? Your IP might be persona non grata. Supabase’s Fail2ban auto-bans after 2-3 bad password guesses (or auth fails). Symptoms: ECONNREFUSED on port 5432, but silent hangs on API calls.

Check dashboard > Reports > Failed logins. Banned? Wait 30 mins or ping support with your IP. Corporate firewalls love blocking Supabase domains too—test from home VPN-off.

IPv4 vs IPv6 trips folks: Dashboard Connect shows if IPv4’s live. No? Direct connections only, or beg support.

From connection refused guide, whitelist *.supabase.co on 443/80. Curl test:

curl -I https://yourproject.supabase.co/rest/v1/ # Should 401 (expected)

Fails? Network’s blocking.

Realtime Connection Hangs with AutoConnectRealtime

AutoConnectRealtime = true is convenient but deadly if realtime endpoints flake. It spins up WebSocket during init, and network hiccups? Infinite wait.

Toggle it off:

var options = new SupabaseOptions { AutoConnectRealtime = false };

Works? Realtime’s jammed. Enable manually post-init: await supabase.Realtime.ConnectAsync();. Docs hint realtime needs separate perms—wiki confirms.

Deadlocks lurk too: Async calls in auth callbacks freeze the client, per troubleshooting. No awaits in onAuthStateChange.

Async Initialization Pitfalls in Services

Constructor init? Can’t await there—async void hell. Services like this hang:

// BAD - hangs in DI container
public class MyService 
{
 private readonly Client _supabase;
 public MyService() // No async ctor!
 {
 _supabase = new Client(url, key, options);
 _ = _supabase.InitializeAsync(); // Fire-and-forget disaster
 }
}

Fix: Factory pattern or lazy init.

public class MyService 
{
 private Client? _supabase;
 private readonly SemaphoreSlim _initLock = new(1,1);

 public async Task<Client> GetSupabaseAsync()
 {
 if (_supabase != null) return _supabase;
 await _initLock.WaitAsync();
 try 
 {
 _supabase ??= new Client(url, key, options);
 await _supabase.InitializeAsync();
 }
 finally { _initLock.Release(); }
 return _supabase;
 }
}

GitHub issue nails it—async init demands proper async handling.

Debugging and Timeout Fixes

Still stuck? Crank logging. No built-in verbose, but wrap in Task.Run with timeout:

var initTask = _supabase.InitializeAsync();
if (await Task.WhenAny(initTask, Task.Delay(TimeSpan.FromSeconds(30))) == initTask)
{
 // Success
}
else
{
 throw new TimeoutException("Init timed out");
}

Long queries? Session timeouts cap at 60s—bump compute or use SET statement_timeout = '120s';.

Reddit/StackOverflow echo: Permissions gatekeep post-init pulls. Test .From<T>().Get() early.

Exhausted options? Postgres connect docs table it out.

Sources

1. C# API Reference | Supabase Docs
2. Connect to your database | Supabase Docs
3. Why is my supabase API call not returning? | Supabase Docs
4. Timeouts | Supabase Docs
5. Avoiding timeouts in long running queries | Supabase Docs
6. Initialize supabase client · Issue #3 · supabase-community/supabase-csharp
7. GitHub - supabase-community/supabase-csharp
8. Home · supabase-community/supabase-csharp Wiki
9. Error: “Connection refused” when trying to connect to Supabase database | Supabase Docs

Conclusion

Most Supabase C# client hangs boil down to URL/key mixups or realtime/network snags—swap to anon key and AutoConnectRealtime = false, then layer back features. Async service init needs lazy loading to avoid deadlocks. Test incrementally, log everything, and you’ll connect reliably. If it’s deeper (bans, perms), dashboard + support sorts it fast. Happy coding—no more staring at spinners.