Monitor targets

target says what a monitor watches, and change_detection says how a difference becomes a change. Only name and target are required.

import ContextDev from "context.dev";

const client = new ContextDev({ apiKey: process.env.CONTEXT_DEV_API_KEY });

const monitor = await client.monitors.create({
  name: "Terms of service",
  target: { type: "page", url: "https://example.com/legal/terms" },
});
console.log(monitor.id, monitor.change_detection.type);

import os
from context.dev import ContextDev

client = ContextDev(api_key=os.environ["CONTEXT_DEV_API_KEY"])

monitor = client.monitors.create(
    name="Terms of service",
    target={"type": "page", "url": "https://example.com/legal/terms"},
)
print(monitor.id, monitor.change_detection.type)

require "cgi/core"
require "context_dev"

client = ContextDev::Client.new(api_key: ENV.fetch("CONTEXT_DEV_API_KEY"))

monitor = client.monitors.create(
  name: "Terms of service",
  target: {type: "page", url: "https://example.com/legal/terms"},
)
puts monitor.id, monitor.change_detection.type

package main

import (
	"context"
	"fmt"
	"os"

	contextdev "github.com/context-dot-dev/context-go-sdk/v2"
	"github.com/context-dot-dev/context-go-sdk/v2/option"
)

func main() {
	client := contextdev.NewClient(option.WithAPIKey(os.Getenv("CONTEXT_DEV_API_KEY")))

	monitor, err := client.Monitors.New(context.Background(), contextdev.MonitorNewParams{
		Name: "Terms of service",
		Target: contextdev.MonitorNewParamsTargetUnion{
			OfPage: &contextdev.MonitorNewParamsTargetPage{
				Type: "page",
				URL:  "https://example.com/legal/terms",
			},
		},
	})
	if err != nil {
		panic(err)
	}
	fmt.Println(monitor.ID, monitor.ChangeDetection.Type)
}

<?php
require __DIR__.'/vendor/autoload.php';

use ContextDev\Client;

$client = new Client(apiKey: getenv('CONTEXT_DEV_API_KEY'));

$monitor = $client->monitors->create(
    name: "Terms of service",
    target: ["type" => "page", "url" => "https://example.com/legal/terms"],
);
echo $monitor->id, " ", $monitor->changeDetection->type, PHP_EOL;

curl https://api.context.dev/v1/monitors \
  -H "Authorization: Bearer $CONTEXT_DEV_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Terms of service",
    "target": { "type": "page", "url": "https://example.com/legal/terms" }
  }'

This page target has no instructions, so detection is inferred as exact, and the monitor runs daily.

Change detection

Target	Detection
`page` without `instructions`	`exact`
`page` with `instructions`	`semantic`
`sitemap`	`exact`
`extract`	`semantic`

Omit change_detection and it’s inferred as shown. Any other pair returns 400, including exact with page instructions and semantic without them. Semantic detection takes an optional confidence_threshold from 0 to 1 (default 0.75). The judge rates each confirmed difference:

It matters, with confidence at or above the threshold: reported as a change, and the baseline moves to the new content.
It matters, with confidence below the threshold: not reported yet. The baseline stays, so the next run checks the same difference again.
It doesn’t matter: not reported, and the baseline takes the new content silently.

Page

Watch the visible text of one page.

Field	Default	Notes
`url`	Required	Public `http(s)` URL.
`include_selectors`	Main content	CSS selectors for the regions to watch, combined in document order. Omit it or send `[]` for automatic main-content extraction.
`exclude_selectors`	None	CSS selectors to remove before comparing. They win over `include_selectors`.
`instructions`	None	1–2,000 characters on what matters and what to ignore. Makes detection `semantic`.
`normalize_whitespace`	`true`	Ignore whitespace-only differences. Set `false` when spacing matters.

Each selector list takes up to 50 selectors of 1–2,048 characters. Every run fetches the page fresh. If the filtered page has no usable text, the run fails with fetch_failed and the old baseline stays. An exact monitor reports the first fetch that differs from the baseline. A semantic monitor fetches the page again to confirm a difference before the judge sees it.

{
  "name": "Status page incidents",
  "target": {
    "type": "page",
    "url": "https://status.example.com",
    "instructions": "Report new or resolved incidents. Ignore uptime percentages.",
    "include_selectors": ["#incidents"]
  },
  "change_detection": { "type": "semantic", "confidence_threshold": 0.8 }
}

Sitemap

Watch a sitemap for URLs that are added or removed.

Field	Default	Notes
`url`	Required	A URL ending in `.xml` or `.xml.gz` is read as that sitemap file. Any other URL reads the domain’s sitemaps.
`include`	None	Up to 50 path patterns of 1–200 characters, such as `/blog/`. A pattern must match the whole path, and `` matches anything.
`exclude`	None	Path patterns to leave out, in the same format.
`max_urls`	`5000`	1–10,000. The cap applies to URLs as read, before `include` and `exclude`.

URLs are normalized (lowercase host, no trailing slash or fragment) and kept only for the site and its subdomains. When a run sees a difference, it reads the sitemap again and reports only the URLs both reads agree on.

{
  "name": "New blog posts",
  "target": {
    "type": "sitemap",
    "url": "https://example.com/sitemap.xml",
    "include": ["/blog/*"],
    "exclude": ["/blog/tag/*"]
  }
}

Extract

Watch the pages of a site that matter for your instructions.

Field	Default	Notes
`url`	Required	Root URL to start from.
`instructions`	Required	1–2,000 characters on which pages and facts to track and which changes to report.
`schema`	Summary and key points	Optional JSON Schema, up to 20,000 characters serialized and 12 levels deep.
`max_pages`	`10`	1–50 pages to track.
`max_depth`	None	0–10 link levels from `url`. `0` tracks only `url`.
`follow_subdomains`	`false`	Also consider pages on subdomains.

A discovery crawl picks up to max_pages pages that fit instructions and schema, and it refreshes that set periodically. Each run fetches the tracked pages again, confirms text differences, and asks the judge whether they matter. Extract monitors never compare extracted data. schema gives the judge extra context and shapes the baseline data on Retrieve a monitor, which refreshes about once a day. Changes contain diffs, summaries, and evidence, not data in your schema’s shape.

{
  "name": "Competitor product lineup",
  "target": {
    "type": "extract",
    "url": "https://example.com",
    "instructions": "Track product names, plan tiers, and feature limits. Ignore blog posts and job listings.",
    "max_pages": 20,
    "max_depth": 2
  }
}

Update a target

PATCH /v1/monitors/{monitor_id} replaces target as a whole, so send every field you want to keep, including instructions and selectors. Send change_detection together with target. If you leave it out, the monitor keeps its current detection type even when the new target implies another one. For example, adding instructions to an exact monitor without "change_detection": {"type": "semantic"} leaves it exact.

{
  "target": {
    "type": "page",
    "url": "https://example.com/legal/terms",
    "instructions": "Report changes to data retention, liability, or termination terms.",
    "include_selectors": ["article"]
  },
  "change_detection": { "type": "semantic" }
}

Any change to target or change_detection, including confidence_threshold, discards the baseline and queues a new baseline run, which reports no change. Updating name, tags, schedule, status, or webhook keeps the baseline.

Limits and errors

An unsupported target and detection pair, or a target URL that isn’t public, returns 400 INPUT_VALIDATION_ERROR with a details list of each problem. See Limits and errors for every limit and error code.

Monitors overview: create a monitor with a webhook.
Runs and changes: what each target’s changes contain.
Update a monitor reference

Get started

Web data

Company and people data

Automation

Account and billing

Production

Change detection

Page

Sitemap

Extract

Update a target

Limits and errors

​Change detection

​Page

​Sitemap

​Extract

​Update a target

​Limits and errors

​Related

Change detection

Page

Sitemap

Extract

Update a target

Limits and errors

Related