Receive webhooks hub C# (.NET) (standard library)
Guide

How to receive webhooks in Azure Functions C# (.NET) receiver + reliable processing

A minimal Azure Functions endpoint is easy to add. Production reliability (verification, retries, idempotency, backpressure) is the hard part — and Hooque makes that part simple.

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Prefer the “no framework” version? Read receive webhooks in C# (.NET).

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TL;DR

  • Treat “receive webhooks in Azure Functions (C# (.NET))” as an ops problem, not just a route handler.
  • Verify the request before parsing/side effects (use a verifySignature(...) stub, then implement provider verification).
  • Return 2xx quickly; move work to a worker/queue to avoid timeouts and retries.
  • Assume retries and design idempotency (dedupe by event id + unique constraints).
  • Log + store raw payloads for replayable debugging.
  • If you need one workflow across many providers, centralize ingest + standardize consumption.

Want the standard-library version and shared pitfalls? Read receive webhooks in C# (.NET) .

Anti-patterns

  • Doing business logic inline in the Azure Functions (C# (.NET)) request handler.
  • Parsing/transforming the body before verification (breaks signing inputs).
  • Returning 2xx before authenticity is proven.
  • Skipping idempotency (retries become double side effects).

Need deeper implementation details? Start with Webhook API.

Table of contents

  1. Why it's hard
  2. Minimal receiver
  3. With Hooque
  4. REST loop
  5. SSE loop
  6. FAQ

Why it's hard in production

Frameworks help you build endpoints. They don’t solve retries, replay attacks, or backpressure by default.

Verify authenticity + stop replays

Use a verifySignature(...) stub here, then implement real verification + replay defense for each provider.

Read the guide

Assume retries (duplicates are optional)

Treat every delivery as at-least-once and make side effects idempotent (DB constraints, dedupe keys).

Read the guide

Don’t do work in the request path

Ack fast, process async. Otherwise timeouts, deploys, and spikes turn into missed webhooks.

Read the guide

Debug with real payloads

Save the exact body + headers so you can replay deterministically after a fix.

Read the guide

Add monitoring + alerts early

Track delivered vs rejected, processing latency, queue depth, and error rates.

Read the guide

Iterate locally without losing events

Tunnels help, but durable capture + replay removes the “my laptop was asleep” problem.

Read the guide

Minimal receiver (Azure Functions)

Keep verification as a stub here, then implement provider-specific verification + replay protection in the webhook security guide . For the standard-library version and shared pitfalls, see receive webhooks in C# (.NET) . 

using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;

public static class WebhooksFn
{
  static void VerifySignature(IHeaderDictionary headers, byte[] body)
  {
    // don't compromise on security
    // TODO: implement provider-specific signature verification
  }

  static void ProcessData(byte[] body)
  {
    // TODO: your business logic (DB writes, external API calls, etc.)
  }

  [FunctionName("Webhooks")]
  public static async Task<IActionResult> Run(
    [HttpTrigger(AuthorizationLevel.Function, "post", Route = "webhooks")] HttpRequest req)
  {
    using var ms = new MemoryStream();
    await req.Body.CopyToAsync(ms);
    var body = ms.ToArray();
    
    VerifySignature(req.Headers, body);

    // What happens if it fails or times out?
    // Most providers retry -> duplicates unless you designed idempotency.
    ProcessData(body);

    // IMPORTANT: ack fast to avoid timeouts and duplicate deliveries.
    return new ContentResult { Content = "ok", ContentType = "text/plain", StatusCode = 200 };
  }
}

Hooque turns any webhook into a reliable queue.

Jump to REST Jump to SSE

Non-obvious scenario: you can’t expose a port

In real deployments, the hardest part is often “where does this endpoint run?” (NAT, corporate networks, locked-down environments, short-lived preview deployments). Hooque decouples inbound receiving from processing so your Azure Functions app doesn’t need to be the public receiver.

The easy path: receive with Hooque + consume forever

Receive once (durably), then process from a queue. Your Azure Functions app doesn’t have to be the public receiver.

  • Centralize provider-specific verification and reduce “raw body” pitfalls.
  • Buffer spikes and deployments so you don’t drop deliveries.
  • Use explicit Ack / Nack / Reject to control retries.
  • Replay from the UI after a fix (no guessing what payload was sent).

Want the generic patterns? Read Webhook API and migrate to queue-based processing.

Hooque REST polling loop (runs forever)

Poll the queue forever and handle each event outside the provider’s request path. 

// .NET 8+ (HttpClient)
// Runs forever: poll /next, ack/nack/reject explicitly.
using System;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Net.Http.Json;
using System.Text.Json;
using System.Threading.Tasks;

var nextUrl = Environment.GetEnvironmentVariable("HOOQUE_QUEUE_NEXT_URL")
  ?? "https://app.hooque.io/queues/<consumerId>/next";
var token = Environment.GetEnvironmentVariable("HOOQUE_TOKEN") ?? "hq_tok_replace_me";

using var client = new HttpClient();
client.Timeout = TimeSpan.FromSeconds(30);

while (true)
{
  var msg = await GetNextMessageAsync();
  if (msg == null)
  {
    await Task.Delay(1000);
    continue;
  }

  try
  {
    await ProcessDataAsync(msg.Payload, msg.Meta);
    await AckAsync(msg);
  }
  catch (Exception e)
  {
    await NackAsync(msg, e);
  }
}

async Task<Msg?> GetNextMessageAsync()
{
  try
  {
    using var req = new HttpRequestMessage(HttpMethod.Get, nextUrl);
    req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);

    using var resp = await client.SendAsync(req);
    if (resp.StatusCode == System.Net.HttpStatusCode.NoContent) return null;
    
    var body = await resp.Content.ReadAsStringAsync();
    if (!resp.IsSuccessStatusCode)
    {
      Console.WriteLine($"next() failed: {(int)resp.StatusCode} {body}");
      await Task.Delay(2000);
      return null;
    }

    var metaRaw = resp.Headers.TryGetValues("X-Hooque-Meta", out var vals) ? (vals.FirstOrDefault() ?? "{}") : "{}";
    var meta = JsonDocument.Parse(metaRaw).RootElement;

    return new Msg(body, meta);
  }
  catch (Exception e)
  {
    Console.WriteLine($"Worker connection err: {e.Message}");
    await Task.Delay(2000);
    return null;
  }
}

async Task ProcessDataAsync(string payload, JsonElement meta)
{
  Console.WriteLine($"event: {meta.GetProperty("messageId").GetString()}");
}

async Task AckAsync(Msg msg)
{
  if (msg.Meta.TryGetProperty("ackUrl", out var ackUrl))
  {
    await PostAsync(ackUrl.GetString()!, null);
  }
}

async Task NackAsync(Msg msg, Exception e)
{
  string? url = null;
  if (msg.Meta.TryGetProperty("nackUrl", out var nackUrl)) url = nackUrl.GetString();
  else if (msg.Meta.TryGetProperty("rejectUrl", out var rejectUrl)) url = rejectUrl.GetString();

  if (url != null)
  {
    await PostAsync(url, e.Message);
  }
}

async Task PostAsync(string url, string? reason)
{
  using var req = new HttpRequestMessage(HttpMethod.Post, url);
  req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
  if (reason != null)
  {
    req.Content = JsonContent.Create(new { reason });
  }
  await client.SendAsync(req);
}

record Msg(string Payload, JsonElement Meta);

Hooque SSE stream consumer (runs forever)

Stream events in real time and reconnect forever on disconnects. 

// .NET 8+ — SSE consumer (HttpClient)
// Runs forever: connect to /stream, handle "message" events, ack/nack/reject explicitly.
using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Net.Http.Json;
using System.Runtime.CompilerServices;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

var streamUrl = Environment.GetEnvironmentVariable("HOOQUE_QUEUE_STREAM_URL")
  ?? "https://app.hooque.io/queues/<consumerId>/stream";
var token = Environment.GetEnvironmentVariable("HOOQUE_TOKEN") ?? "hq_tok_replace_me";
using var client = new HttpClient { Timeout = Timeout.InfiniteTimeSpan };

while (true)
{
  try
  {
    await foreach (var msg in GetMessageStreamAsync())
    {
      try
      {
        await ProcessDataAsync(msg.Payload, msg.Meta);
        await AckAsync(msg);
      }
      catch (Exception e)
      {
        await NackAsync(msg, e);
      }
    }
  }
  catch (Exception e)
  {
    Console.WriteLine("stream error: " + e.Message);
    await Task.Delay(2000);
  }
}

async IAsyncEnumerable<Msg> GetMessageStreamAsync([EnumeratorCancellation] CancellationToken cancellationToken = default)
{
  using var req = new HttpRequestMessage(HttpMethod.Get, streamUrl);
  req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
  req.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("text/event-stream"));

  using var resp = await client.SendAsync(req, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
  resp.EnsureSuccessStatusCode();

  using var stream = await resp.Content.ReadAsStreamAsync(cancellationToken);
  using var reader = new StreamReader(stream);
  string? evt = null;
  var data = new StringBuilder();

  while (!reader.EndOfStream)
  {
    var line = await reader.ReadLineAsync(cancellationToken);
    if (line == null) break;
    if (line.StartsWith(":")) continue;
    if (line.Length == 0)
    {
      if (evt == "message" && data.Length > 0)
      {
        using var doc = JsonDocument.Parse(data.ToString());
        var meta = doc.RootElement.GetProperty("meta").Clone();
        yield return new Msg(data.ToString(), meta);
      }
      evt = null;
      data.Clear();
      continue;
    }
    if (line.StartsWith("event:")) evt = line.Substring(6).Trim();
    if (line.StartsWith("data:"))
    {
      if (data.Length > 0) data.Append('\n');
      data.Append(line.Substring(5).TrimStart());
    }
  }
}

async Task ProcessDataAsync(string payload, JsonElement meta)
{
  Console.WriteLine($"event: {meta.GetProperty("messageId").GetString()}");
}

async Task AckAsync(Msg msg)
{
  if (msg.Meta.TryGetProperty("ackUrl", out var ackUrl))
  {
    await PostAsync(ackUrl.GetString()!, null);
  }
}

async Task NackAsync(Msg msg, Exception e)
{
  string? url = null;
  if (msg.Meta.TryGetProperty("nackUrl", out var nackUrl)) url = nackUrl.GetString();
  else if (msg.Meta.TryGetProperty("rejectUrl", out var rejectUrl)) url = rejectUrl.GetString();

  if (url != null)
  {
    await PostAsync(url, e.Message);
  }
}

async Task PostAsync(string url, string? reason)
{
  using var req = new HttpRequestMessage(HttpMethod.Post, url);
  req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
  if (reason != null)
  {
    req.Content = JsonContent.Create(new { reason });
  }
  await client.SendAsync(req);
}

record Msg(string Payload, JsonElement Meta);

FAQ

Answers tailored to Azure Functions, plus shared webhook production guidance.

How do I get the raw request body in Azure Functions?

General: Signature verification typically requires the raw body bytes (before JSON parsing). Ensure your middleware stack does not transform the body before verification.

How Hooque helps: With Hooque, provider delivery goes to a managed ingest endpoint. Your worker consumes from a queue using REST or SSE, so the “raw body vs parsed body” pitfall is mostly confined to ingest configuration.

What status code should I return for webhooks in Azure Functions (C# (.NET))?

General: Usually return a fast 2xx after validating authenticity and basic schema. Timeouts and 5xx commonly trigger retries.

How Hooque helps: Hooque acknowledges ingest immediately and persists the payload. Your worker acks/nacks/rejects explicitly after processing.

Do I need signature verification in Azure Functions (C# (.NET))?

General: Yes, unless the sender is fully trusted and on a private network. A public endpoint without verification is easy to forge and easy to replay.

How Hooque helps: Hooque can verify at ingest for supported providers or using generic strategies. Either way, your worker receives a normalized meta object and can stay focused on processing.

Why do I see duplicate webhook events in Azure Functions (C# (.NET))?

General: Retries are normal: timeouts, transient network failures, and 5xx responses all produce duplicates. Design idempotency around event ids and side-effect boundaries.

How Hooque helps: Hooque makes delivery outcomes explicit (ack/nack/reject) and provides replay/inspection so you can fix issues without guessing what was received.

How do I test webhooks locally in Azure Functions (C# (.NET))?

General: You can use a tunnel, but local dev still breaks on sleep, VPNs, clock skew, and signature-byte mismatches.

How Hooque helps: With Hooque you can avoid inbound locally: receive events into a durable queue and pull/stream to your laptop, then replay from the UI after changes.

Should I use REST polling or SSE streaming for webhook processing?

General: Use REST polling for simple batch workers and environments without long-lived connections. Use SSE for low-latency “process as it arrives” flows.

How Hooque helps: Hooque supports both: `GET /next` for polling and `GET /stream` for streaming. Both include meta with ready-to-call ack/nack/reject URLs.

Start processing webhooks reliably

Use Azure Functions for your app, and keep webhook processing as a simple run-forever consumer loop with explicit ack/nack/reject control.

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