Continuous monitoring runs accessibility scans on an ongoing, automated schedule, while periodic scans are conducted at set intervals like monthly or quarterly. The core distinction is frequency: continuous monitoring catches new issues as content changes, and periodic scans provide snapshots at predetermined points in time.
| Key Point | What It Means |
|---|---|
| Continuous Monitoring | Scans run on a daily or near-daily schedule, identifying new accessibility issues soon after they appear |
| Periodic Scans | Scans run at fixed intervals (weekly, monthly, quarterly), providing a conformance snapshot at each checkpoint |
| Detection Window | Continuous monitoring shortens the gap between when an issue is introduced and when it is flagged |
| Scope of Both | Both approaches are automated and detect approximately 25% of accessibility issues; neither replaces a manual audit |
How Continuous Monitoring Works
Continuous monitoring uses scheduled scans that run daily or multiple times per week. The scanner loads each page in the defined scope, evaluates the HTML, CSS, and ARIA attributes against WCAG success criteria, and logs any new issues it identifies.
Because scans run frequently, teams receive alerts closer to the time a change was made. If a developer deploys a new feature on Tuesday and the scan runs that night, the issue appears in reports by Wednesday morning. This shorter feedback loop makes it easier to trace an issue back to the code change that caused it.
How Periodic Scans Work
Periodic scans follow a fixed calendar. An organization might schedule scans once a month before a conformance review, or quarterly to align with release cycles. The scanner performs the same automated checks as a continuous scan, but the results represent a single point in time.
Between scan dates, any new issues introduced go undetected until the next scheduled run. A monthly scan means an accessibility issue could exist on a live site for up to 30 days before it is flagged.
When Organizations Use Each Approach
Organizations with frequently updated content, such as e-commerce sites, news publishers, or web applications with regular deployments, tend to use continuous monitoring. The volume of changes makes a monthly snapshot insufficient for tracking regression.
Periodic scans fit organizations with more static websites or those in early stages of building an accessibility scan schedule. A quarterly or monthly cadence still provides structured visibility into automated conformance status without requiring daily scan infrastructure.
What Neither Approach Replaces
Both continuous monitoring and periodic scans are automated. They evaluate code against a set of programmatic rules. That means both detect approximately 25% of WCAG conformance issues. The remaining 75% requires human evaluation, including screen reader testing, keyboard testing, and contextual review of content meaning and structure.
Increasing scan frequency does not increase scan coverage. A daily scan and a monthly scan check the same criteria. The difference is how quickly new issues within that 25% are identified, not whether more types of issues are caught.
Choosing a Scan Cadence
The right cadence depends on how often site content changes and how quickly the team needs to know about regressions. Continuous monitoring is the stronger choice for active codebases. Periodic scans work for sites that update infrequently or for teams that review results in batch cycles rather than continuously.
Many organizations start with periodic scans and move toward continuous monitoring as their accessibility program matures and their remediation workflows become more responsive.