Frequently Asked Questions
Everything you need to know about OnChange. If your question is not answered here, reach out to us at contact@sairo.app.
What is OnChange?
OnChange is a website change detection and monitoring platform. It watches web pages and API endpoints on your behalf and alerts you the moment something changes. You can monitor entire pages, specific elements using CSS selectors, or API responses. Notifications are delivered via email, Slack, Discord, or custom webhooks.
How does OnChange detect changes?
OnChange periodically loads your target URL in a real browser environment (or makes an HTTP request for API endpoints), captures the content, and compares it against the previous snapshot. When a difference is detected, it generates a diff showing exactly what changed and sends notifications through your configured channels.
What types of websites can I monitor?
OnChange can monitor any publicly accessible web page, including JavaScript-heavy single-page applications, server-rendered HTML pages, and REST API endpoints. It uses a headless browser for page rendering, so dynamic content generated by JavaScript frameworks (React, Vue, Angular, etc.) is fully supported.
How often can OnChange check for changes?
Check intervals range from every 10 seconds to daily, depending on your plan. Sub-minute intervals (10, 20, 30 seconds) are available for time-sensitive monitoring like flash sale detection. Most users find 5-15 minute intervals work well for routine monitoring.
What notification channels are supported?
OnChange supports email, Slack (via incoming webhooks), Discord (via webhooks), and custom HTTP webhooks. You can configure multiple notification channels per monitor, and different monitors can use different channels. Webhook payloads include structured data that can be parsed by automation tools like Zapier or Make.
Can I monitor specific parts of a page?
Yes. CSS selector targeting lets you monitor a specific HTML element instead of the whole page. This is the recommended approach for most use cases because it eliminates noise from dynamic content like ads, timestamps, and personalized sections. You can use the visual element picker in the dashboard or manually enter CSS selectors.
Does OnChange support visual (screenshot) comparisons?
Yes. OnChange takes screenshots of monitored pages and provides visual diffs that highlight pixel-level differences. This is particularly useful for detecting layout changes, styling updates, image replacements, and other visual modifications that text-based monitoring might miss.
Can I monitor API endpoints?
Yes. OnChange can monitor REST API endpoints and detect changes in JSON response payloads. You can configure custom headers, authentication tokens, HTTP methods, and request bodies. JSON diffs show exactly which fields changed, were added, or were removed. See our API monitoring use case for details.
Is there a free plan?
Yes. OnChange offers a free tier that lets you get started with a limited number of monitors and check intervals. This is enough for personal projects and basic monitoring needs. Paid plans unlock higher check frequencies, more monitors, and additional features. Visit the pricing section on our homepage for current plan details.
How is pricing structured?
Pricing is based on the number of monitors and check frequency. Higher-frequency checks and more monitors require higher-tier plans. All plans include access to all notification channels, CSS selector targeting, visual diffs, and API access. There are no hidden fees for alerts or data storage.
Is my data secure?
OnChange takes security seriously. All data is transmitted over TLS (HTTPS). We are SOC 2 Type II compliant and GDPR compliant. Monitored page data is stored securely and is only accessible to your account. We do not share or sell your monitoring data. For enterprise security requirements, contact us at contact@sairo.app.
How long is change history retained?
Change history retention depends on your plan. Free plans retain history for a limited period, while paid plans offer extended retention. Enterprise plans can be configured for custom retention periods. All change records include timestamps, before/after snapshots, and diff data for the duration of the retention period.
Can I access OnChange via an API?
Yes. OnChange provides a full REST API that lets you create, update, delete, and query monitors programmatically. You can also retrieve change history, diff data, and account information via the API. This enables integration with CI/CD pipelines, custom dashboards, and automation workflows.
Can I monitor pages that require login?
For API endpoints, you can configure custom headers with authentication tokens (Bearer tokens, API keys, basic auth). For web pages behind login walls, support depends on the authentication method. Contact us at contact@sairo.app if you need to monitor authenticated web pages.
What happens if a monitored page goes down?
If OnChange cannot load a monitored page (due to a server error, timeout, or network issue), it records the failure and can optionally alert you about the outage. This effectively provides basic uptime monitoring alongside change detection. The monitor continues checking on schedule and resumes normal operation when the page becomes available again.
Can I export my monitoring data?
Yes. You can export change history and monitoring data via the REST API. This allows you to build custom reports, import data into spreadsheets or BI tools, or archive records for compliance purposes. API responses are in standard JSON format for easy integration.
How do I get support?
For general questions, check this FAQ page and our how-to guides. For account-specific issues or feature requests, contact us at contact@sairo.app. We aim to respond to all support requests within one business day.
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