The pain

You ship a redesign on Tuesday. The new template silently changes og:image. You find out from a Slack share that looks broken on Friday afternoon.

The industry calls this template drift — one CSS or partial change cascades across thousands of pages and nobody notices until rankings move or shares stop converting.

Existing solutions (ContentKing, Conductor, Lumar Monitor) start at $61,000/year and target enterprise crawl budgets. Drift monitoring brings the same workflow to single-URL granularity at a price the rest of us can afford.

What it watches

For each URL you pin:

Audit score — does the weighted 0-100 number change?
Title and description — text, pixel-width, rewrite-likelihood signal.
Canonical — points elsewhere? Now a chain?
og:image — URL changed, dimensions changed, content-type changed, byte-size changed.
Twitter card — type changed, image silent-downgrade triggered (under 300x157).
JSON-LD — schema type changed, required property dropped, content cross-check mismatch surfaced.
AI crawler row — robots.txt changed for any of the 11 monitored AI bots.
Sitemap presence — URL added to or removed from sitemap.xml.
Indexability verdict — flipped from indexable to conflict / excluded.

How it works

Pin a URL from the extension or from /account/monitor.
We re-scan it on a schedule (daily by default; webhook trigger available for CI/CD).
Each scan is diffed against the previous one.
If anything changed at or above your alert threshold, you get a notification.

Notification channels

Email — daily digest by default, or instant on warning-or-worse change.
Slack webhook — paste a webhook URL, get a card per alert with score + top 3 changed rules.
Discord webhook — same as Slack.
Webhook trigger endpoint — POST to https://metaspry.com/api/monitor/trigger?url=... from your CI/CD pipeline to force a re-scan + alert on deploy.

Thresholds

To avoid notification fatigue:

Default: alert only on warning-or-worse rule changes. Cosmetic changes (description rewording, image alt text) are tracked silently and visible in the diff view.
Aggressive: alert on any change.
Critical only: alert only when the page becomes uncrawlable / unindexable / loses required tags.

Quotas

Tier	Monitored URLs	Re-scan frequency	Webhooks
Free	-	-	-
Pro	50	Daily	Slack + Discord
Team	500	Daily + on-demand webhook	Slack + Discord + per-channel

What you’ll see in the UI

/account/monitor will list your pinned URLs:

Score (current + delta vs last scan)
Last-change date
Sparkline of score over time
Click into per-URL detail for the timeline + diff viewer

Per-URL detail shows:

Score timeline (chart)
Diff viewer: added / removed / value-changed tags, color-coded by severity
Download per-scan CSV
Notification settings per URL (channels + threshold)

Differences from competitors

Tool	Granularity	Frequency	Price
Metaspry Pro	Per-URL	Daily + webhook	$9/mo
Conductor / ContentKing	Whole site	10-min	$61,000+/yr
SE Ranking change monitor	URL list	Daily	$39+/mo
Lumar Monitor	Whole site	Configurable	$15,000+/yr
Sitebulb Cloud	Whole site	Scheduled crawl	$95+/mo

The differentiator is per-URL focus + price. You probably don’t need to crawl 50,000 URLs every 10 minutes. You need to know if the 50 pages that drive your traffic broke overnight.

Audit rules - what gets scored
AI crawler signals - what gets watched in the Site tab
Indexability conflicts - the four-signal cross-check