Professor Sloth

Free web performance master class

Learn about web performance and how to make your site faster, delivered straight to your inbox.

  • Sell more stuff

    User's stay longer and purchase more from fast websites and stores. Fast images and resources will keep your website fast and users happy, so they buy more things.

  • Less developer time

    Point your developer team right at the problem with our reports and reduce engineering time from hours to minutes.

  • Fix problems fast

    Get notified of performance problems before Google notices or rankings are impacted.

Big Resources

Big, Slow, or Blocking Resources

Quickly discover the resources that are too big, too slow, or blocking the rest of your website from loading as fast as it could.

Big, Slow, or Blocking Resources
  • Find the pages impacted

    Find the pages impacted

    Quickly find the pages where big, slow, and blocking resources are used to get to the root cause of performance problems in minutes.

  • Fix unexpected large images

    Fix unexpected large images

    That blog post doesn't need a 3 MB header image, does it? Find those unexpected giant images before they slow down your scores.

  • Remove performance blockers

    Remove performance blockers

    Find the complex JavaScript and blocking CSS that's slowing down your site.

Request Metrics helped me quickly identify and resolve a crippling performance issue.
David Walsh
David Walsh
Owner, David Walsh Blog
Third-Party Tracking

Know the performance of your third-parties and vendors

Understand the performance impact and costs of all your third-party vendors and external JavaScript, and respond quickly when it changes.

Know the performance of your third-parties and vendors
  • Realtime dependencies

    Realtime dependencies

    Continuously updated list of everything your website depends on, right now.

  • Vendor performance impact

    Vendor performance impact

    Understand the performance cost and trade-offs for every vendor you add to your website.

  • Discover caching problems

    Discover caching problems

    Find opportunities to boost performance with better caching and compression controls.

Request Metrics showed us all the unused marketing pixels and vendor rubbish that was slowing down our users.
Anton Ball
Anton Ball
Full Stack Team Lead, Doist
Resource Changes

New and Changed Resources

Accurate listings of all the images, scripts, and third-parties that have been added or removed from your website. Stay on top of changes that can impact your performance.

New and Changed Resources
  • Audit website changes

    Audit website changes

    Get a full list of all the resources added and removed from your website everyday.

  • Know about new vendors

    Know about new vendors

    Stay informed when vendors are added or removed from your websites tag managers.

  • See impact of resources

    See impact of resources

    Know when important and slow resources get added or removed from your site.