Alerts for newly broken links, not the whole 404 list
An alert means a link was in good standing and then failed twice as 404 or 410. It does not mean “here is every broken URL again.”
No card required. 1 site and 200 pages on the free plan.
When an alert is created
The baseline crawl never alerts, even if it finds 404s. On a later crawl, a URL becomes a new break only if it returns 404 or 410, the previous crawl also had it broken, it was eligible to alert, and it was not already a confirmed break. Eligibility starts off for baseline 404s. A link that later returns a working status becomes eligible again, so a future double failure can alert.
Where the alert shows up
Every plan adds the row to New breaks on the site page, with the time, URL, source page, and status code. Pro can also email the account and POST JSON to a public webhook you save. The email subject is “Mortise: N new broken link(s) on host” and the body lists up to 50 URLs. The webhook event name is new_breaks, signed with HMAC-SHA256 of the raw body.
There is no separate test-alert button. Delivery runs when a real new break is confirmed. Until then, use the dashboard lists to see crawl results.
Pro POSTs the JSON below to your webhook URL with X-Mortise-Signature: sha256= of the raw body, using the site’s signing secret. The live body is compact JSON. This sample is pretty-printed and illustrative, not a customer. Slack and Discord are not built in.
{
"event": "new_breaks",
"host": "example.com",
"site_id": 1,
"crawl_id": 18,
"breaks": [
{
"url": "https://cdn.example.net/files/spec-2024.pdf",
"source_url": "https://example.com/resources",
"status_code": 404
}
]
}
What will not alert
Known baseline 404s, a single unconfirmed 404, timeouts, HTTP 429, HTTP 5xx, and blocked 401 or 403 responses do not create a new-break alert. A link that disappears from a later crawl is removed from the current broken list. Disappearing is not treated as a recovery, and it is not an alert by itself.
Questions
Why two crawls?
One failed fetch is often a blip. Mortise waits for a second 404 or 410 in a row before it calls the link newly broken.
Does Free include email?
No. Free is the dashboard. Email and webhooks are Pro features, and outbound email also has to be configured on Mortise.
Can the same URL alert every day?
Not while it stays broken. After it alerts, it stays ineligible until a crawl sees it working again.