Webhooks

WEBHOOK

webhook

{
  "event_type": "review_auto.completed",
  "flagged": true,
  "internal_session_id": "80782a99-04b0-426b-8c59-f6a68ec08a26",
  "external_session_id": "9dad26de-d17b-47e9-8d6a-2a096cdff151",
  "policies": {
    "f714c7a0-0779-4838-894f-d05e9e6cd61f": {
      "flagged": false,
      "flagged_source": ["text"],
      "name": "Prohibited Content"
    },
    "5dd86eea-f13a-4a97-aa1e-ca5f76b63255": {
      "flagged": true,
      "flagged_source": ["text"],
      "name": "PII Detection"
    }
  }
}

import time, hmac, hashlib

## Step 1: Get secret and raw body
whitecircle_signing_secret = 'MY_WHITECIRCLE_SIGNING_SECRET'
request_body = request.text
# '{"event_type":"review_auto.completed","flagged":true,"internal_session_id":"2e9f6747-045a-4713-9a60-8c166203fce7","policies":{"4fa864e4-9af1-43b6-9fbb-33627980041f":{"flagged":true,"flagged_source":["text"],"name":"Policy A"}}}'*/

## Step 2: Validate timestamp freshness
timestamp = request.headers['X-Whitecircle-Request-Timestamp'] # '1752847035'
time.time() - int(timestamp) < 5 * 60 # if True...

## Step 3: Build signature base string
sig_basestring = 'v0:' + timestamp + ':' + request_body
# 'v0:1752847035:{"event_type":"review_auto.completed","flagged":true,"internal_session_id":"2e9f6747-045a-4713-9a60-8c166203fce7","policies":{"4fa864e4-9af1-43b6-9fbb-33627980041f":{"flagged":true,"flagged_source":["text"],"name":"Policy A"}}}'

## Step 4: Compute HMAC-SHA256 signature
my_signature = 'v0=' + hmac.new(whitecircle_signing_secret.encode(), sig_basestring.encode(), hashlib.sha256).hexdigest()
# 'v0=37a8f9210398d5f370b2a10a4413ca16075d373e0c418d14c83ad71354912fbd'

## Step 5: Compare signatures
whitecircle_signature = request.headers['X-Whitecircle-Signature']
hmac.compare_digest(my_signature, whitecircle_signature) # if True...

## Step 6: Process the event
request_body['event_type']...

## Step 7: Return 200 OK
return '200 OK'

White Circle can send HTTP POST requests to your server when specific events occur. This allows you to build custom integrations and automate workflows based on session reviews and strike-action updates.

Available Events

Event Type	Description
`session.violated`	A session has been flagged as violating one or more Policies.
`review_manual.in_progress`	Someone from your team starts a manual review of the session and changes a model-generated verdict (for example, marking something as “false positive” or “false negative”).
`review_manual.completed`	Reviewer finished the manual check and submitted the changes.
`review_auto.completed`	Our larger model has finished automatically checking the session.
`strike.action.updated`	A user’s effective strike action changed (for example `warn` → `suspend`).
`strike.action.expired`	A temporary strike action expired.

Setting Up Webhooks

Open Workspace Settings

Go to your Workspace Settings → Integrations page.

Add Webhook Endpoint

Click on the Webhooks integration and add your webhook URL.

Configure Events

Select which event types you want to receive notifications for.

Save

Click Save to activate the webhook.

You’ll see the signing secret when creating a webhook. You’ll need it later to verify the authenticity of incoming events.

Receiving events

Your webhook URL will receive a request for each event type you select. One request = one event.

sessions.violated
review_* events
strike.action.* events

The session.violated event includes all flagged Policies for the session.

For review_manual.* and review_auto.completed events, only the changed verdicts are included. For example, if five Policies are enabled in your environment and our larger model (or your colleague reviewing the session) changes the verdict on two of them, we will send you only the revised policies.

strike.action.updated and strike.action.expired include the user’s current strike action state (action, action_expires_at) and strike list. Use these events to synchronize account restrictions in your app.

Error handling

Please return an HTTP 200 OK for each event you successfully receive on your Webhook URL.

Failure conditions

We consider any of these scenarios a single failure condition:

We are unable to negotiate or validate your server’s SSL certificate.
We wait longer than 3 seconds to receive a valid response from your server.
We receive any other response than an HTTP 200-series response.

Retries

We’ll retry a failed request up to 3 times in a gradually increasing timetable:

The first retry will be sent nearly immediately.
The second retry will be attempted after 2 seconds.
The third and final retry will be sent after 4 seconds.

You can check the number of total requests and retries per last 24 hours on the platform.

Verifying requests from White Circle

With the help of signed secrets, you can verify whether requests from White Circle are authentic.

Understanding signed secrets

You can verify requests from White Circle by verifying signatures using your signing secret. On each HTTP request that White Circle sends, White Circle adds an X-Whitecircle-Signature HTTP header (or x-whitecircle-signature — header names are meant to be case-insensitive, so the letter case should not be assumed). The signature is created by hashing the request body with the SHA-256 function, and combining it with an HMAC signing secret. The resulting signature is unique to each request and doesn’t contain any secret information, keeping your app secure. Request signing follows this pattern:

Your app receives a request from White Circle.
Your app computes a signature based on the request.
You make sure the signature you’ve computed matches the signature on the request.

Let’s go over the recipe for this signature.

Validating a request

Grab your White Circle Signing Secret and the request body

>>> whitecircle_signing_secret = 'MY_WHITECIRCLE_SIGNING_SECRET'
>>> request_body = request.text
'{"event_type":"review_auto.completed","violation":true,"internal_id":"2e9f6747-045a-4713-9a60-8c166203fce7","violations":{"4fa864e4-9af1-43b6-9fbb-33627980041f":{"violation":true,"violation_source":["text"]},"35822a7e-dc4d-4b9a-a27b-c088e8c73f1c":{"violation":false,"violation_source":["text"]},"069167bb-bda5-4b2a-b012-e3ca78944951":{"violation":false,"violation_source":["text"]}}}'

Use the raw request body, without headers, before it has been deserialized from JSON or other forms. For example, in Python’s Flask, use request.get_data() before accessing any other methods on the request in order to get the raw request payload, without performing JSON deserialization.

Extract the timestamp header from the request

The signature depends on the timestamp to protect against replay attacks. While you’re extracting the timestamp, check to make sure that the request occurred recently. In this example, we verify that the timestamp does not differ from local time by more than five minutes.

>>> import time
>>> timestamp = request.headers['X-Whitecircle-Request-Timestamp']
'1752847035'
>>> time.time() - int(timestamp) < 5 * 60
True

Concatenate the version number, the timestamp, and the request body together, using a colon (`:`) as a delimiter

>>> sig_basestring = 'v0:' + timestamp + ':' + request_body
'v0:1752847035:{"event_type":"review_auto.completed","violation":true,"internal_id":"2e9f6747-045a-4713-9a60-8c166203fce7","violations":{"4fa864e4-9af1-43b6-9fbb-33627980041f":{"violation":true,"violation_source":["text"]},"35822a7e-dc4d-4b9a-a27b-c088e8c73f1c":{"violation":false,"violation_source":["text"]},"069167bb-bda5-4b2a-b012-e3ca78944951":{"violation":false,"violation_source":["text"]}}}'

Hash the resulting string, using the signing secret as a key, and taking the hex digest of the hash

>>> import hmac
>>> import hashlib
>>> my_signature = 'v0=' + hmac.new(whitecircle_signing_secret.encode(), sig_basestring.encode(), hashlib.sha256).hexdigest()
'v0=37a8f9210398d5f370b2a10a4413ca16075d373e0c418d14c83ad71354912fbd'

Compare the resulting signature to the header on the request

>>> whitecircle_signature = request.headers['X-Whitecircle-Signature']
>>> hmac.compare_digest(my_signature, whitecircle_signature)
True

Done!

That’s it! You may now proceed with processing the update.

Request schema

Session/Review Event
Strike Action Event

{
  "event_type": "review_auto.completed",
  "flagged": true,
  "internal_session_id": "80782a99-04b0-426b-8c59-f6a68ec08a26",
  "external_session_id": "9dad26de-d17b-47e9-8d6a-2a096cdff151",
  "policies": {
    "f714c7a0-0779-4838-894f-d05e9e6cd61f": {
      "flagged": false,
      "flagged_source": ["text"],
      "name": "Prohibited Content"
    },
    "5dd86eea-f13a-4a97-aa1e-ca5f76b63255": {
      "flagged": true,
      "flagged_source": ["text"],
      "name": "PII Detection"
    }
  }
}

{
  "event_type": "strike.action.updated",
  "user_id": "user-123",
  "user_ids": ["user-123"],
  "action": "suspend",
  "action_expires_at": "2026-03-20T10:00:00Z",
  "strikes": [
     {
         "policy": {
            "id": "8d3d8fad-0df7-443f-a6df-5445e48a8eaf",
            "name": "adult",
            "severity": "high"
        },
        "severity": "high",
        "points": 10,
        "created_at": 1770612473,
        "expires_at": 1771217273,
        "reason": "session.flagged",
        "internal_session_id": "5f8a31d6-4b2f-4e61-88d5-cc537e4af79e",
        "external_session_id": "session-456"
    }
  ]
}

import time, hmac, hashlib

## Step 1: Get secret and raw body
whitecircle_signing_secret = 'MY_WHITECIRCLE_SIGNING_SECRET'
request_body = request.text
# '{"event_type":"review_auto.completed","flagged":true,"internal_session_id":"2e9f6747-045a-4713-9a60-8c166203fce7","policies":{"4fa864e4-9af1-43b6-9fbb-33627980041f":{"flagged":true,"flagged_source":["text"],"name":"Policy A"}}}'*/

## Step 2: Validate timestamp freshness
timestamp = request.headers['X-Whitecircle-Request-Timestamp'] # '1752847035'
time.time() - int(timestamp) < 5 * 60 # if True...

## Step 3: Build signature base string
sig_basestring = 'v0:' + timestamp + ':' + request_body
# 'v0:1752847035:{"event_type":"review_auto.completed","flagged":true,"internal_session_id":"2e9f6747-045a-4713-9a60-8c166203fce7","policies":{"4fa864e4-9af1-43b6-9fbb-33627980041f":{"flagged":true,"flagged_source":["text"],"name":"Policy A"}}}'

## Step 4: Compute HMAC-SHA256 signature
my_signature = 'v0=' + hmac.new(whitecircle_signing_secret.encode(), sig_basestring.encode(), hashlib.sha256).hexdigest()
# 'v0=37a8f9210398d5f370b2a10a4413ca16075d373e0c418d14c83ad71354912fbd'

## Step 5: Compare signatures
whitecircle_signature = request.headers['X-Whitecircle-Signature']
hmac.compare_digest(my_signature, whitecircle_signature) # if True...

## Step 6: Process the event
request_body['event_type']...

## Step 7: Return 200 OK
return '200 OK'

Headers

X-Whitecircle-Request-Timestamp

string

required

Unix timestamp (seconds) when the request was signed to protect against replay attacks.

X-Whitecircle-Signature

string

required

Signature for the request body computed as HMAC-SHA256 over 'v0:{timestamp}:{raw_body}', prefixed with 'v0='.

Body

application/json

Option 1
Option 2

event_type

enum<string>

required

Type of the event

Available options:

session.violated,

review_manual.in_progress,

review_manual.completed,

review_auto.completed

violation

boolean

required

Whether any Policy violations were detected in the session

internal_id

string

required

Unique internal identifier for the session

violations

object

required

Map of policy IDs to their changed verdicts (only changed policies included)

Hide child attributes

violations.{key}

object

Policy object. Key is policy ID.

Hide child attributes

violations.{key}.violation

boolean

required

Whether a violation was detected for this policy

violations.{key}.violation_source

enum<string>[]

required

Sources where violations were detected (includes only triggered violations)

Available options:

text,

image

Example:

{
  "violation": true,
  "violation_source": ["text"]
}

external_id

string | null

Optional external identifier provided by client

Response

Successfully received

⌘I

{
  "event_type": "review_auto.completed",
  "flagged": true,
  "internal_session_id": "80782a99-04b0-426b-8c59-f6a68ec08a26",
  "external_session_id": "9dad26de-d17b-47e9-8d6a-2a096cdff151",
  "policies": {
    "f714c7a0-0779-4838-894f-d05e9e6cd61f": {
      "flagged": false,
      "flagged_source": ["text"],
      "name": "Prohibited Content"
    },
    "5dd86eea-f13a-4a97-aa1e-ca5f76b63255": {
      "flagged": true,
      "flagged_source": ["text"],
      "name": "PII Detection"
    }
  }
}

import time, hmac, hashlib

## Step 1: Get secret and raw body
whitecircle_signing_secret = 'MY_WHITECIRCLE_SIGNING_SECRET'
request_body = request.text
# '{"event_type":"review_auto.completed","flagged":true,"internal_session_id":"2e9f6747-045a-4713-9a60-8c166203fce7","policies":{"4fa864e4-9af1-43b6-9fbb-33627980041f":{"flagged":true,"flagged_source":["text"],"name":"Policy A"}}}'*/

## Step 2: Validate timestamp freshness
timestamp = request.headers['X-Whitecircle-Request-Timestamp'] # '1752847035'
time.time() - int(timestamp) < 5 * 60 # if True...

## Step 3: Build signature base string
sig_basestring = 'v0:' + timestamp + ':' + request_body
# 'v0:1752847035:{"event_type":"review_auto.completed","flagged":true,"internal_session_id":"2e9f6747-045a-4713-9a60-8c166203fce7","policies":{"4fa864e4-9af1-43b6-9fbb-33627980041f":{"flagged":true,"flagged_source":["text"],"name":"Policy A"}}}'

## Step 4: Compute HMAC-SHA256 signature
my_signature = 'v0=' + hmac.new(whitecircle_signing_secret.encode(), sig_basestring.encode(), hashlib.sha256).hexdigest()
# 'v0=37a8f9210398d5f370b2a10a4413ca16075d373e0c418d14c83ad71354912fbd'

## Step 5: Compare signatures
whitecircle_signature = request.headers['X-Whitecircle-Signature']
hmac.compare_digest(my_signature, whitecircle_signature) # if True...

## Step 6: Process the event
request_body['event_type']...

## Step 7: Return 200 OK
return '200 OK'

First Steps

Use Cases

Integrations

Events

Conditions

Artifacts

Policy

Metric

User

Available Events

Setting Up Webhooks

Receiving events

Error handling

Failure conditions

Retries

Verifying requests from White Circle

Understanding signed secrets

Validating a request

Request schema

Headers

Body

Response

​Available Events

​Setting Up Webhooks

​Receiving events

​Error handling

​Failure conditions

​Retries

​Verifying requests from White Circle

​Understanding signed secrets

​Validating a request

​Request schema

Headers

Body

Response

Available Events

Setting Up Webhooks

Receiving events

Error handling

Failure conditions

Retries

Verifying requests from White Circle

Understanding signed secrets

Validating a request

Request schema