Verid guides
How every part of Verid works, start to finish - what a monitor is made of, how to get data out of any page with CSS selectors, XPath, JSONPath, Regex, full-page hashing or AI, and how alerts are decided and delivered. Every guide includes real config and real output.
Start here
What a Verid Monitor Is Made Of
Every monitor is five decisions: where to look, how often, what to capture, when it counts as a change, and who to tell. Learn those five and the rest of Verid is configuration.
How a Verid Check Runs, End to End
Follow one scheduler check end-to-end: fetch, extract, compare, decide, record, and deliver. Knowing what each stage logs makes monitors debuggable.
Which Extraction Method Should You Use?
A decision path through all six extraction methods, with the question to ask at each fork and the failure mode of each wrong turn.
Extraction methods
How to Use CSS Selector Extraction
Target HTML elements by class, ID, or attribute and pull out their text. The fastest method for well-structured pages.
.product .priceHow to Use XPath Extraction
Navigate the full document tree with XPath expressions. More powerful than CSS selectors for complex conditions, attribute access, and partial text matching.
//span[@id="price"]How to Use JSONPath Extraction
Query JSON API responses and embedded JSON data using JSONPath expressions - the JSON equivalent of XPath.
$.items[0].priceHow to Use Regex Extraction
Run regular expressions against raw page source to extract versioned strings, counts, prices, or any pattern that appears in the HTML or text.
v(\d+\.\d+\.\d+)How to Use Full Page Hash
Detect any meaningful change on a page without configuring selectors. Verid normalizes the HTML and computes a hash - if anything changes, you hear about it.
sha256(normalized html)How to Use AI (LLM) Extraction
Describe what you want to extract in plain English and let the AI figure out the rest. Works on any page, including JavaScript-heavy and unstructured content.
"the current price in USD"Alerting & predicates
How Diff Predicates Decide What Alerts You
A change in a field and an alert are two different things. The predicate is the rule in between - here is every type, a worked example for each, and the gate that quietly blocks the ones people expect to fire.
Percent and Absolute Thresholds (and Why Yours May Never Fire)
Numeric predicates parse your extracted string with parseFloat. "$1,299" parses to NaN, and NaN never triggers. Here is how to extract a number that works.