Add PostHog export documentation and images for Cloudflare Workers observability

- Introduced a new guide on exporting OpenTelemetry logs to PostHog, detailing prerequisites, configuration steps, and troubleshooting tips.
- Added two images to illustrate the PostHog logs view and the Cloudflare destination configuration for logs.
- Updated the existing documentation to include PostHog as a supported observability provider.

Author: rafaeelaudibert

src/assets/images/workers-observability/posthog-example-destination-modal.png

@@ -28,6 +28,7 @@ Below are common OTLP endpoint formats for popular observability providers. Refe
 | [**Grafana Cloud**](/workers/observability/exporting-opentelemetry-data/grafana-cloud/) | `https://otlp-gateway-{region}.grafana.net/otlp/v1/traces`   | `https://otlp-gateway-{region}.grafana.net/otlp/v1/logs`[^1] |
 | [**Axiom**](/workers/observability/exporting-opentelemetry-data/axiom/)                 | `https://api.axiom.co/v1/traces`                             | `https://api.axiom.co/v1/logs`                               |
 | [**Sentry**](/workers/observability/exporting-opentelemetry-data/sentry/)               | `https://{HOST}/api/{PROJECT_ID}/integration/otlp/v1/traces` | `https://{HOST}/api/{PROJECT_ID}/integration/otlp/v1/logs`   |
+| [**PostHog**](/workers/observability/exporting-opentelemetry-data/posthog/)             | Not supported                                                | `https://us.i.posthog.com/i/v1/logs`                         |
 | [**Datadog**](https://docs.datadoghq.com/opentelemetry/setup/otlp_ingest/)              | Coming soon, pending release from Datadog                    | `https://otlp.{SITE}.datadoghq.com/v1/logs`                  |
 
 :::note[Authentication]

src/assets/images/workers-observability/posthog-example.png

@@ -0,0 +1,161 @@
+---
+pcx_content_type: how-to
+title: Export to PostHog
+sidebar:
+  order: 5
+---
+
+import {WranglerConfig} from "~/components";
+
+PostHog is a product analytics platform that helps you understand user behavior and debug issues. By exporting your Cloudflare Workers application telemetry to PostHog, you can:
+
+- Correlate logs with user sessions, events, and error tracking data
+- Query and filter logs by severity, attributes, and custom properties
+- Connect application logs to session replays for full debugging context
+
+![PostHog logs view with attributes expanded and a timeline view at the top](~/assets/images/workers-observability/sentry-example.png)
+
+This guide will walk you through configuring your Cloudflare Worker application to export OpenTelemetry-compliant logs to PostHog.
+
+## Prerequisites
+
+Before you begin, ensure you have:
+
+- An active [PostHog account](https://app.posthog.com/signup) (free tier available)
+- A deployed Worker that you want to monitor
+- Your PostHog project API key
+
+## Step 1: Get your PostHog project API key
+
+1. Log in to your [PostHog account](https://app.posthog.com/)
+2. Navigate to the [**Project settings**](https://app.posthog.com/settings/project#selectedSetting=variables&setting=variables)
+3. Find your **Project API key** in the project details section
+4. Copy the API key - this is the same key used for capturing events and exceptions
+
+The API key should look something like: `phc_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx`
+
+## Step 2: Determine your PostHog region endpoint
+
+PostHog has different endpoints depending on your data region:
+
+| Region | Logs Endpoint |
+| ------ | ------------- |
+| **US** (default) | `https://us.i.posthog.com/i/v1/logs` |
+| **EU** | `https://eu.i.posthog.com/i/v1/logs` |
+
+You can find your region in your PostHog project settings or by checking the URL when logged into PostHog (either `us.posthog.com` or `eu.posthog.com`).
+
+## Step 3: Configure Cloudflare Logs destination
+
+:::caution
+Cloudflare Workers Observability only supports exporting **logs** to PostHog at this time. Exporting **traces** to PostHog is not currently supported.
+:::
+
+Now you'll create a destination in the Cloudflare dashboard that points to PostHog.
+
+1. Navigate to your Cloudflare account's [Workers Observability](https://dash.cloudflare.com/?to=/:account/workers-and-pages/observability/pipelines) section
+2. Click **Add destination**
+3. Configure your logs destination:
+   - **Destination Name**: `posthog-logs` (or any descriptive name)
+   - **Destination Type**: Select **Logs**
+    - PostHog does not support importing Cloudflare traces at this time.
+   - **OTLP Endpoint**: Your PostHog logs endpoint (e.g., `https://us.i.posthog.com/i/v1/logs` or `https://eu.i.posthog.com/i/v1/logs`)
+   - **Custom Headers**: Add the authentication header:
+     - Header name: `Authorization`
+     - Header value: `Bearer <your-project-api-key>` (e.g., `Bearer phc_xxxxx...`)
+4. Click **Save**
+
+![Cloudflare destination configuration for PostHog logs with destination name, type selection, OTLP endpoint, and custom headers](~/assets/images/workers-observability/posthog-example-destination-modal.png)
+
+## Step 4: Configure your Worker
+
+With your destination created in the Cloudflare dashboard, update your Worker's configuration to enable logs export.
+
+<WranglerConfig>
+
+```json
+{
+  "observability": {
+    "logs": {
+      "enabled": true,
+      // Must match the destination name in the dashboard
+      "destinations": ["posthog-logs"]
+    }
+  }
+}
+```
+
+</WranglerConfig>
+
+After updating your configuration, deploy your Worker for the changes to take effect.
+
+:::note
+It may take a few minutes after deployment for logs to appear in PostHog.
+:::
+
+## Step 5: View logs in PostHog
+
+Once your Worker is deployed and receiving traffic:
+
+1. Log in to your [PostHog account](https://app.posthog.com/)
+2. Navigate to the **Logs** section in the left sidebar
+3. Your Worker logs will appear with severity levels, timestamps, and attributes
+
+You can filter logs by:
+- **Severity level** (trace, debug, info, warn, error, fatal)
+- **Time range**
+- **Custom attributes** added to your log entries
+- **Keywords** in log messages
+
+## Adding custom attributes to logs
+
+You can add custom attributes to your logs using standard `console` methods with structured data:
+
+```javascript
+export default {
+  async fetch(request, env) {
+    // Basic logging
+    console.log("Processing request");
+
+    // Logs with additional context
+    console.info("User action", {
+      userId: "user_123",
+      action: "api_call",
+      path: new URL(request.url).pathname
+    });
+
+    // Error logging with details
+    console.error("Request failed", {
+      error: "Connection timeout",
+      retryCount: 3
+    });
+
+    return new Response("OK");
+  }
+};
+```
+
+These attributes will be searchable and filterable in the PostHog logs interface.
+
+## Troubleshooting
+
+### Logs not appearing in PostHog
+
+1. **Verify your API key**: Ensure you're using your project API key (starts with `phc_`), not a personal API key
+2. **Check the endpoint region**: Confirm you're using the correct regional endpoint (US or EU) matching your PostHog instance
+3. **Confirm destination status**: In the Cloudflare dashboard, verify your destination shows a recent successful delivery
+4. **Check sampling rate**: If you've configured a sampling rate, not all logs may be sent
+
+### Authentication errors
+
+If you see authentication errors in your destination status:
+
+- Ensure the Authorization header value includes `Bearer ` prefix followed by your API key
+- Verify the API key has not been revoked or regenerated in PostHog
+- Alternatively, you can pass the token as a query parameter by using `https://us.i.posthog.com/i/v1/logs?token=<your-project-api-key>` as your endpoint
+
+## Related resources
+
+- [PostHog Logs documentation](https://posthog.com/docs/logs)
+- [PostHog Getting Started with Logs](https://posthog.com/docs/logs/start-here)
+- [OpenTelemetry Logs specification](https://opentelemetry.io/docs/specs/otel/logs/)