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Developer Guidelines for NLM Web Page Accessibility

The National Library of Medicine (NLM) is committed to serving the entire public, and that means striving to ensure that all pages of our site are accessible to the greatest possible number of people and Assistive Technology devices.

Accessibility and Web Standards

In order to design sites that are accessible and that work well in modern browsers, web authors must:

  • Include accessibility planning from the beginningof the project to avoid costly retrofitting and project delays.
  • Pass the HHS Accessibility Compliance Checklists or receive a waiver as specified in the checklists, before posting.
  • Validate all HTML to the HTML5 standard, including the DOCTYPE and XML namespace declaration described on our Web Application/Site Development Guidelines
  • Validate all style sheets.

Additional Resources


If you have questions about accessibility, contact

Last Reviewed: March 15, 2023