Create a webhook subscription

Creates a webhook subscription with event types and receiver URL, returning its signing secret once.

POST https://app.upfour.io/v1/webhook-subscriptions

A real request. Sending it changes data in your up4 account.

Authorization

AuthorizationA pls_ key. It stays in this browser tab. Needs webhook.write.

Body

urlrequired http or https URL of the receiver. A host that resolves to a private or otherwise blocked address range is refused.

More fields1

active Defaults to true, also on update: a PUT without active switches a disabled subscription back on.

1 more field is only available in JSON.

Headers

Idempotency-KeyheaderGenerated automatically when empty. How it works

Sent directly from your browser to https://app.upfour.io/v1. Mutating calls get an automatic Idempotency-Key when the field is empty.

Request

Responsenot sent yet

Fill in a key and press Send request (⌘↵).
The answer appears here.

scope webhook.write beta Idempotency-Key supported returns 201

Body

application/json required 3 fields

eventsstring[]required

Event types to deliver, at least one; blanks and duplicates are dropped. The service does not check the names, an event that is never published simply never arrives. Published: monitor.created, monitor.updated, monitor.deleted, monitor.status_changed, monitor.degraded_changed, monitor.unstable, monitors.bulk_updated, incident.opened, incident.acknowledged, incident.resolved, incident.reopened, incident.escalated, incident.propagated, incident.partially_recovered, heartbeat.missed, heartbeat.recovered, status_page.update_published, status_page.report_published, webhook.test.

urlstring (uri)required

http or https URL of the receiver. A host that resolves to a private or otherwise blocked address range is refused.

All other fields1 fields

activeboolean · nullable

Defaults to true, also on update: a PUT without active switches a disabled subscription back on.

Returns

A successful request returns 201 with application/json.

Response fields 1 top-level fields

Field Type Description

data WebhookSubscriptionCreated

WebhookSubscriptionCreated · 11 fields

Field	Type	Description
`active`	boolean
`created_at`	string (date-time)
`events`	string[] · nullable
`failure_count`	integer
`id`	uuid
`org_id`	uuid
`secret`	string	Signing secret of the subscription, `whsec_` plus 64 hex characters. Returned by this call only; list, update and read calls never include it. Store it now: a lost secret cannot be read back, only replaced with POST /webhook-subscriptions/{subscriptionID}/rotate-secret. The old secret stops signing at once.
`updated_at`	string (date-time)
`url`	string
`disabled_at`	string (date-time)	Set while the subscription is switched off, by active: false or by the delivery worker after repeated failures.
`last_delivery_at`	string (date-time)

Errors

Only the errors this operation can return. Every error uses the same envelope.

Status	Code	Meaning
400	`bad_request`	The request is malformed or fails validation.
402	`billing_action_unavailable`	The Company's billing state does not allow this action. When: A metered or limited action while the billing state, such as paused or without credit, blocks it; details holds the action and billing_state. Fix: Top up the credit or change the plan, then retry.
403	`permission_denied`	The credentials do not permit this action.
503	`quota_gate_unavailable`	The limit check itself failed, so the action was not carried out. When: The quota service could not decide while the request ran. Fix: Retry in a moment; nothing was changed.
403 / 429	`quota_limit_reached`	The Company already holds the most webhook subscriptions it may have; `error.details` carries `purpose` and `limit`. When: Counters and concurrency limits answer 429 with Retry-After, inventory and capacity limits answer 403; details holds purpose, limit and window. Fix: On 429 wait Retry-After seconds; on 403 free something up, request a higher limit where details.raise_request is true, or buy an extension. `quota_limit_reached` (window `total`): the Company already holds the most of these it may have. `error.details` carries `purpose` and `limit`; remove one or ask support for a higher limit.

Every call can also return unauthorized (401), rate_limit_exceeded (429) or internal_error (500 / 502). See Responses and errors.

curl -s -X POST "https://app.upfour.io/v1/webhook-subscriptions" \ -H "Authorization: Bearer $UP4_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "active": true, "events": [ "incident.opened", "incident.resolved", "monitor.status_changed" ], "url": "https://example.com/hooks/up4" }'

const res = await fetch("https://app.upfour.io/v1/webhook-subscriptions", { method: "POST", headers: { Authorization: `Bearer ${process.env.UP4_API_KEY}`, "Content-Type": "application/json", }, body: JSON.stringify({ active: true, events: [ "incident.opened", "incident.resolved", "monitor.status_changed", ], url: "https://example.com/hooks/up4", }), }); console.log(res.status, await res.json());

import os import requests res = requests.post( "https://app.upfour.io/v1/webhook-subscriptions", headers={"Authorization": f"Bearer {os.environ['UP4_API_KEY']}"}, json={ "active": True, "events": [ "incident.opened", "incident.resolved", "monitor.status_changed", ], "url": "https://example.com/hooks/up4", }, ) print(res.status_code, res.json())

package main import ( "fmt" "io" "net/http" "os" "strings" ) func main() { payload := strings.NewReader(`{ "active": true, "events": [ "incident.opened", "incident.resolved", "monitor.status_changed" ], "url": "https://example.com/hooks/up4" }`) req, _ := http.NewRequest("POST", "https://app.upfour.io/v1/webhook-subscriptions", payload) req.Header.Set("Authorization", "Bearer "+os.Getenv("UP4_API_KEY")) req.Header.Set("Content-Type", "application/json") res, err := http.DefaultClient.Do(req) if err != nil { panic(err) } defer res.Body.Close() out, _ := io.ReadAll(res.Body) fmt.Println(res.StatusCode, string(out)) }

<?php $payload = <<<'JSON' { "active": true, "events": [ "incident.opened", "incident.resolved", "monitor.status_changed" ], "url": "https://example.com/hooks/up4" } JSON; $ch = curl_init("https://app.upfour.io/v1/webhook-subscriptions"); curl_setopt_array($ch, [ CURLOPT_CUSTOMREQUEST => "POST", CURLOPT_RETURNTRANSFER => true, CURLOPT_HTTPHEADER => [ "Authorization: Bearer " . getenv("UP4_API_KEY"), "Content-Type: application/json", ], CURLOPT_POSTFIELDS => $payload, ]); $response = curl_exec($ch); echo curl_getinfo($ch, CURLINFO_RESPONSE_CODE), " ", $response, "\n"; curl_close($ch);

{ "data": { "active": true, "created_at": "2026-10-27T09:00:00Z", "events": [ "incident.opened", "incident.resolved", "monitor.status_changed" ], "failure_count": 0, "id": "00000000-0000-4000-8000-000000000001", "org_id": "00000000-0000-4000-8000-000000000002", "secret": "whsec_••••", "updated_at": "2026-10-27T09:00:00Z", "url": "https://example.com/hooks/up4" } }

{ "error": { "code": "quota_limit_reached", "message": "The Company already holds the most webhook subscriptions it may have; error.details carries purpose and limit.", "request_id": "req_…" } }