feat(flags): Document self-serve feature flags integrations

docs/organization/integrations/feature-flag/self-serve/index.mdx

@@ -0,0 +1,57 @@
+---
+title: Self-Serve
+sidebar_order: 1
+description: Learn about Sentry's self-serve feature-flag integrations.
+---
+
+## Evaluation Tracking
+
+Sentry can track flag evaluations as they happen within your application.  Flag evaluations will appear in the "Feature Flag" section of Issue Details page as a table, with "suspect" flag predictions highlighted in yellow. Learn more about how to interact with feature flag insights within the Sentry UI by reading the [Issue Details page documentation](/product/issues/issue-details/#feature-flags).
+
+### Set Up Evaluation Tracking
+
+To set up evaluation tracking visit the [explore page](/product/explore/feature-flags/) and select the language and SDK of your choice. Not using a supported SDK? That's okay. We support self-serve integrations with your existing system.
+
+To set up self-serve evaluation tracking visit one of our supported languages pages:
+* [JavaScript](/platforms/javascript/configuration/integrations/self-serve/)
+* [Python](/platforms/python/integrations/self-serve/)
+
+## Change Tracking
+
+Sentry can track changes to feature flag definitions and report suspicious feature flag edits.
+
+Sentry offers a change tracking feature which functions as an audit-log of feature flag changes. When a feature flag definition changes in your back-end you can emit a web hook to Sentry.
+
+### API Documentation
+
+If you're using a self-serve integration it means you will likelyneed to write code to support this endpoint. This section documents our authentication proceedures as well as the resource's fields and structure.
+
+#### Authentication
+
+Authentication is performed using a "signing secret". The "signing secret" must be used to sign the web hook payload in your feature flagging system. Signing the payload with your secret produces a "signature". Sentry needs this signature so it can compare the results of our signing function to yours. Both sides must use the same signing function. Sentry uses a HMAC SHA256 hex-digest of the web hook payload. In Python this function looks like:
+
+```python
+def hmac_sha256_hex_digest(secret: str, message: bytes):
+    return hmac.new(secret.encode(), message, hashlib.sha256).hexdigest()
+```
+
+The result of this function must be sent as a header to Sentry: `X-Sentry-Signature signature_result`.
+
+#### API Blueprint
+
+[An API blueprint is available at this permalink](https://github.com/getsentry/sentry/blob/ed324708947ca26392d6579ed76b93fc94a61ab6/src/sentry/flags/docs/api.md#create-generic-flag-log-post). We strive to keep this page updated. Be sure to check the latest master branch for new protocol versions. We will always maintain backwards compatibility so there is no harm in implementing an old version. However, new versions might introduce new features.
+
+### Set Up Change Tracking
+
+Enabling Change Tracking is a three step process. To get started visit the [feature-flags settings page](https://sentry.io/orgredirect/organizations/:orgslug/settings/feature-flags) in a new tab. Then follow the steps listed below.
+
+1. **Click the "Add New Provider" button.
+    - One webhook secret can be registered per provider type.
+2. **Register the webhook URL**.
+    - Copy the provided Sentry webhook URL and configure your feature flagging system to emit web hooks to this URL.
+3. **Set the Signing Secret**.
+    - In your feature flagging system's UI retries the "Signing Secret".
+    - Copy the signing secret in the revealed input box and paste it into the input box labeled "Secret" in Sentry.
+    - Save the secret by clicking "Save Secret" in the Sentry fly out.
+
+Once saved Sentry will now accept and authenticate all inbound hooks to your organization's feature flag webhook endpoint.

docs/platforms/javascript/common/configuration/integrations/featureflags.mdx → docs/platforms/javascript/common/configuration/integrations/self-serve.mdx

@@ -1,5 +1,5 @@
 ---
-title: FeatureFlags
+title: Self-Serve Feature Flags Integration
 description: "Learn how to attach custom feature flag data to Sentry error events."
 notSupported:
   - javascript.aws-lambda

docs/platforms/javascript/common/feature-flags/index.mdx

@@ -33,6 +33,6 @@ description: With Feature Flags, Sentry tracks feature flag evaluations in your
 Evaluation tracking requires enabling an SDK integration. Integrations are provider specific. Documentation for supported providers is listed below.
 - [OpenFeature](/platforms/javascript/configuration/integrations/openfeature/)
 - [LaunchDarkly](/platforms/javascript/configuration/integrations/launchdarkly/)
-- [Manual Tracking](/platforms/javascript/configuration/integrations/featureflags/) - if you use an unsupported or in-house provider, you may track evaluations through an API.
+- [Self-Serve](/platforms/javascript/configuration/integrations/self-serve/)
 
 <PlatformContent includePath="feature-flags/enable-change-tracking" />

docs/platforms/python/feature-flags/index.mdx

@@ -16,6 +16,6 @@ Evaluation tracking requires enabling an SDK integration. Integrations are provi
 
 - [OpenFeature](/platforms/python/integrations/openfeature/)
 - [LaunchDarkly](/platforms/python/integrations/launchdarkly/)
-- [Manual Tracking](/platforms/javascript/configuration/integrations/featureflags/) - if you use an unsupported or in-house provider, you may track evaluations through an API.
+- [Self-Serve](/platforms/python/integrations/self-serve/)
 
 <PlatformContent includePath="feature-flags/enable-change-tracking" />

docs/platforms/python/integrations/self-serve/index.mdx

@@ -0,0 +1,50 @@
+---
+title: Self Serve Feature Flags
+description: "Learn how to attach custom feature flag data to Sentry error events."
+---
+
+<PlatformContent includePath="feature-flags/prerelease-alert" />
+
+The Feature Flags integration allows you to manually track feature flag evaluations through an API. These evaluations are held in memory, and in the event an error occurs, sent to Sentry for review and analysis.
+**At the moment, we only support boolean flag evaluations.**
+
+## Install
+
+Install `sentry-sdk` from PyPI.
+
+```bash
+pip install --upgrade 'sentry-sdk'
+```
+
+## Configure
+
+Add `FeatureFlagsIntegration()` to your `integrations` list:
+
+```python
+import sentry_sdk
+from sentry_sdk.integrations.featureflags import FeatureFlagsIntegration
+
+sentry_sdk.init(
+    dsn="___PUBLIC_DSN___",
+    integrations=[
+        FeatureFlagsIntegration(),
+    ],
+)
+```
+
+## Verify
+
+The integration is tested by calling the `add_feature_flag` API before capturing an exception.
+
+```python
+import sentry_sdk
+from sentry_sdk.integrations.featureflags import add_feature_flag
+
+add_feature_flag('test-flag', False)
+
+sentry_sdk.capture_exception(Exception("Something went wrong!"))
+```
+
+Visit the Sentry website and confirm that your error event has recorded the feature flag "test-flag" and its value "false".
+
+<PlatformContent includePath="feature-flags/next-steps" />

docs/product/explore/feature-flags/index.mdx

@@ -30,3 +30,4 @@ Change tracking enables Sentry to listen for additions, removals, and modificati
 
 To set up change tracking, visit the webhook integration documentation for your provider:
 * [LaunchDarkly](/organization/integrations/feature-flag/launchdarkly/#change-tracking)
+* [Self-Serve](/organization/integrations/feature-flag/self-serve/#change-tracking)