C# / .NET WebSocket client

Answer: use System.Net.WebSockets.ClientWebSocket, set x-api-key via Options.SetRequestHeader, connect to wss://pinnfeed.io/v1/stream, subscribe, and reply to ping. Builder (€99/mo).

Sketch#

using var ws = new ClientWebSocket();
ws.Options.SetRequestHeader("x-api-key", Environment.GetEnvironmentVariable("PINNFEED_KEY"));
await ws.ConnectAsync(new Uri("wss://pinnfeed.io/v1/stream"), CancellationToken.None);
// SendAsync UTF-8 JSON subscribe; on ping send {"type":"pong"}

Related: TypeScript, docs.

Trial CTA#

Builder (€99/mo) for the live + prematch WebSocket and closing history. 3-day trial; card required, charged after day 3 unless cancelled. Free delayed REST: signup. Related: answers hub, docs, pricing.

Questions people ask#

Does this work on .NET Framework?#

Prefer modern .NET with ClientWebSocket. Older stacks may need a third-party WS library that can set headers.

Can I use SignalR?#

Not required — the feed is a plain WebSocket, not a SignalR hub.

Is this educational content for adults?#

Yes (18+).