Webhook integration

Cloud

Server v4.x

Custom webhooks

Use custom webhooks to trigger a pipeline from anywhere that can emit a webhook or run a curl command.

Custom webhooks are inbound to CircleCI and are used to trigger pipelines from other services. If you are looking for a way to have a CircleCI pipeline trigger a service, use an outbound webhook.

This section presents some use cases for CircleCI custom webhooks.

Quickstart

Follow these steps to set up and test a custom webhook trigger. Trigger from anywhere that can emit a webhook or run a curl command:

In the CircleCI web app select Projects in the sidebar.
Find your project in the list, select the ellipsis (), and select Project Settings.
Select Triggers in the sidebar.
Select Add Trigger.
Select Custom Webhook from the dropdown menu.
Select Next.
Complete the form fields and options:
- Give your trigger a descriptive name.
- (Optional) Add a description.
- Supply a path to a config.yml file and CircleCI will create a configuration source for you:
Select Save.
You will see a webhook endpoint URL and secret. You can use these to set up your webhook trigger from your external source. Copy the Webhook URL and use it in your trigger source appended with the secret.

The secret will not be shown again so be sure to copy the URL before clicking Done.
You can now test your custom webhook trigger with curl. To trigger your pipeline, copy and paste the following sample request and replace <your-URL> and <your-secret> with the URL and secret that you generated in the previous step:

When triggering via curl, you must use a POST request with content-type: application/json.
```
curl -X POST -H "content-type: application/json" 'https://internal.circleci.com/private/soc/e/<your-URL>?secret=<your-secret>'
```

See our community forum for more details or how to use this functionality with a 3rd party service like DockerHub.

Example: Trigger one pipeline from another

Use a custom webhook to configure one pipeline to trigger a second pipeline. For example, you might need to run a set of integration tests on a repository after you have made a change to a separate repository.

For this example, assume you have two projects in separate repositories:

You can also use this method to trigger one pipeline from another within the same project.

Project A
Project B

When a change is made to Project A, we want the full Project A configuration to be run, and then the Project B pipeline should be triggered. To achieve this, follow these steps:

1. Set up a custom webhook for Project B

Navigate to Project B in the CircleCI web app and set up a custom webhook by following these steps:

In the CircleCI web app select Projects in the sidebar.
Find your project in the list, select the ellipsis (), and select Project Settings.
Select Triggers in the sidebar.
Select Add Trigger.
Select Custom Webhook from the dropdown menu.
Select Next.
Complete the form fields and options:
- Give your trigger a descriptive name.
- (Optional) Add a description.
- Supply a path to a config.yml file and CircleCI will create a configuration source for you:
Select Save.
You will see a webhook endpoint URL and secret. You can use these to set up your webhook trigger from your external source. Copy the Webhook URL and use it in your trigger source appended with the secret.

The secret will not be shown again so be sure to copy the URL before clicking Done.

2. Configure Project A to trigger Project B

Navigate to Project A in the CircleCI web app and set up an environment variable. The value of the environment variable will be the secret from the custom webhook you just set up for Project B.

As an alternative, you can add an environment variable using a context.

In the CircleCI web app select your organization.
Select Projects in the sidebar.
Find your project in the list, select the ellipsis (), and select Project Settings.
Select Environment Variables from the sidebar.
Select Add Environment Variable.
Give your environment variable a name, for example, WEBHOOK_SECRET.

Update your Project A configuration file with a step that will trigger a pipeline for Project B, for example (lines 13-16):

version: 2.1

jobs:
  say-hello:
    docker:
      - image: cimg/base:stable
    steps:
      - checkout
      - run:
          name: example
          command: echo "one step"

      - run:
          name: Kick off new pipeline
          command: |
              curl -X POST -H "content-type: application/json" "https://internal.circleci.com/private/soc/e/6ccfca1c-5ed6-4dcf-96ca-374969d6edcb?secret=${WEBHOOK_SECRET}"

workflows:
  say-hello-workflow:
    jobs:
      - say-hello

Example: Extract custom webhook payload data

The custom webhook body is available by using the pipeline.trigger_parameters.webhook.body pipeline value.

The following example shows how you can use jq to extract values from the webhook payload into environment variables when you want to use them in your configuration.

In this example the webhook body contains a property called branch. jq is installed and used to extract the branch value into an environment variable named WEBHOOK_BRANCH, which is then used in a GitHub clone command.

The command configured in this example uses commands from the jq and GitHub CLI orbs.

commands:
  shallow_clone:
    description: Shallow Git Clone
    steps:
      - gh/setup:
          token: "GITHUB_TOKEN"
      - jq/install
      - run:
          name: Shallow Clone
          environment:
            WEBHOOK_BRANCH: << pipeline.trigger_parameters.webhook.body >> | jq .branch
          command: gh repo clone << pipeline.trigger_parameters.github_app.repo_url >> . -- --depth 10 --branch "$WEBHOOK_BRANCH"

Outbound webhooks

Use outbound webhooks to integrate your CircleCI builds with external services.

For example, you could use Outbound webhooks to:

Build a custom dashboard to visualize or analyze workflow/job events.
Send data to incident management tools (such as PagerDuty).
Use tools like Airtable to capture data and visualize it.
Alert when a workflow is cancelled, then use the API to rerun the workflow.
Trigger notification systems to alert people when workflows/jobs complete.
Build your own automation plugins and tools.

The following sections detail CircleCI outbound webhook structure and protocols.

Quickstart

Projects are limited to 5 outbound webhooks.

Webhooks are set up on a per-project basis, either within the CircleCI app or via API.

To configure webhooks via API see our documentation for Webhooks Public API.

To configure webhooks within the CircleCI app:

In the CircleCI web app select your organization.
Select Projects in the sidebar.
Find your project in the list, select the ellipsis (), and select Project Settings.
In the sidebar select Webhooks
Select Add Webhook
Fill out the webhook form (the table below describes the fields and their intent)
If your receiving API or third party service is set up, select Test Ping Event to send a test event.

The test ping event has an abbreviated payload for ease of testing. See full examples for workflow-completed and job-completed events below.

Field	Required?	Intent
Webhook name	Y	The name of your webhook
URL	Y	The URL the webhook will make POST requests to
Certificate Validation	Y	Ensure the receiving host has a valid SSL certificate before sending an event. You should only leave this unchecked for testing purposes.
Secret token	N	Used by your API/platform to validate incoming data is from CircleCI
Select an event	Y	You must select at least one event that will trigger a webhook

Communication protocol for outbound webhooks

Once set up, a webhook is sent whenever an event occurs on the CircleCI platform.

A webhook is sent using an HTTP POST to the URL that was registered when the webhook was created, with a body encoded using JSON.

CircleCI expects the server that responds to a webhook will return a 2xx response code. If a non-2xx response is received, CircleCI will retry at a later time. If CircleCI does not receive a response to the webhook within a short period of time, CircleCI will assume that delivery has failed, and will retry at a later time. The timeout period is currently 10 seconds.

Webhook requests may be duplicated. To deduplicate (prevent requests from being duplicated for a specific event), use the id property in the webhook payload for identification.

If you have feedback about timeouts and retries, get in touch with our team.

Outbound webhook headers

A number of HTTP headers are set on webhooks, as detailed in the table below.

Header name	Value
`content-type`	`application/json`
`user-agent`	A string indicating that the sender was CircleCI (`CircleCI-Webhook/1.0`).
`circleci-event-type`	The type of event, (`workflow-completed`, `job-completed`, etc)
`circleci-signature`	When present, this signature can be used to verify that the sender of the webhook has access to the secret token.

Validate outbound webhooks

You should validate webhooks as they come in to third party services to verify that they are coming from CircleCI. To support this, when creating a webhook, you can optionally provide a secret token. Each outgoing HTTP request to your service will contain a circleci-signature header. This header will consist of a comma-separated list of versioned signatures.

POST /uri HTTP/1.1
Host: your-webhook-host
circleci-signature: v1=4fcc06915b43d8a49aff193441e9e18654e6a27c2c428b02e8fcc41ccc2299f9,v2=...,v3=...

Currently, the latest (and only) signature version is v1. You should only check the latest signature type to prevent downgrade attacks.

The v1 signature is the HMAC-SHA256 digest of the request body, using the configured signing secret as the secret key.

Here are some example signatures for given request bodies:

Body	Secret Key	Signature
`hello world`	`secret`	`734cc62f32841568f45715aeb9f4d7891324e6d948e4c6c60c0621cdac48623a`
`lalala`	`another-secret`	`daa220016c8f29a8b214fbfc3671aeec2145cfb1e6790184ffb38b6d0425fa00`
`an-important-request-payload`	`hunter123`	`9be2242094a9a8c00c64306f382a7f9d691de910b4a266f67bd314ef18ac49fa`

The following is an example of how you might validate signatures in Python:

import hmac

def verify_signature(secret, headers, body):
    # get the v1 signature from the `circleci-signature` header
    signature_from_header = {
        k: v for k, v in [
            pair.split('=') for pair in headers['circleci-signature'].split(',')
        ]
    }['v1']

    # Run HMAC-SHA256 on the request body using the configured signing secret
    valid_signature = hmac.new(bytes(secret, 'utf-8'), bytes(body, 'utf-8'), 'sha256').hexdigest()

    # use constant time string comparison to prevent timing attacks
    return hmac.compare_digest(valid_signature, signature_from_header)

# the following will return `True`
verify_signature(
    'secret',
    {
        'circleci-signature': 'v1=773ba44693c7553d6ee20f61ea5d2757a9a4f4a44d2841ae4e95b52e4cd62db4'
    },
    'foo',
)

# the following will return `False`
verify_signature(
    'secret',
    {
        'circleci-signature': 'v1=not-a-valid-signature'
    },
    'foo',
)

Outbound webhook event specifications

CircleCI currently offers outbound webhooks for the following events:

Event type	Description	Potential statuses	Included sub-entities
workflow-completed	A workflow has reached a terminal state	"success", "failed", "error", "canceled", "unauthorized"	project, organization, workflow, pipeline
job-completed	A job has reached a terminal state	"success", "failed", "canceled", "unauthorized"	project, organization, workflow, pipeline, job