The intersection of
Design & Performance

At SpeedCurve, we focus on measuring the interplay between design and performance to help you deliver a great, enjoyable and fast experience to your users.

Measuring web performance started 15 years ago with metrics like page load time and total download size. But today's websites and browsers have changed a lot since then. Ajax, lazyloading, preloading, async-loading, custom fonts, and responsive design mean today's websites are more complex. It's been shown that those old metrics no longer correlate to a good user experience.

SpeedCurve's goal is to deliver metrics that give true insight into what users are experiencing. Led by Mark Zeman, a teacher, director & leader in the world of design, and Steve Souders, pioneer of the web performance movement, SpeedCurve is innovating new metrics for tracking how design and code changes affect what users see and how quickly they see it. This combination of focusing on design & performance is highlighted by dashboards that include:

  • filmstrips that show a site's responsive design spanning screen sizes for mobile, tablet and desktop
  • alerts for the number of critical resources that block your page from rendering
  • custom metrics - the most accurate way to measure how quickly users see what matters most
  • visualizations of how fast your site renders compared to your competitors

We help developers, designers and managers demonstrate to the wider organization how fast (or not) the user experience is and how you compare to the competition, enabling you and your team to make better informed decisions.

Joseph Wynn

Joseph is a developer with a diverse background ranging from small web agencies to video streaming services to large organisations like the BBC and Time. His experience has helped him to understand that performance is as much an organisational and communicational challenge as it is a technical one.

He led the engineering team rebuilding the front page of BBC News with a rigorous focus on performance and it's now significantly faster, and drives better user engagement.

Joseph Wynn

Steve Souders

Steve is a pioneer in the world of web performance. Before SpeedCurve, he held positions as Chief Performance Yahoo!, Google's Head Performance Engineer, and Chief Performance Officer at Fastly. Steve "wrote the book" on web performance with High Performance Web Sites, and its follow-up Even Faster Web Sites. He is the creator of many performance tools and services including YSlow, the HTTP Archive, Episodes, ControlJS, and Browserscope. He taught CS193H: High Performance Web Sites at Stanford University and serves as co-chair of Velocity, the web performance and operations conference from O'Reilly.

Steve Souders

Tammy Everts

Tammy has spent the past two decades studying how people use the web. Since 2009, she’s focused on the intersection between web performance, user experience, and business metrics. Her book Time Is Money: The Business Value of Web Performance (O’Reilly, 2016) is a distillation of much of this research (but there’s always more to be learned).

Tammy is a frequent speaker at events like, IRCE, and Smashing Conference. She co-chairs O’Reilly Fluent, the conference for anyone involved in building the modern web. She also co-curates, an ongoing collection of performance case studies.

Tammy Everts

Mark Zeman

Mark comes from a design background but has always been just as passionate about the code. He 
has spent 20 years crafting websites and mobile apps in a variety of roles, 
including running his own design studio, lecturing at New Zealand's best design school and leading teams to deliver some on New Zealand's largest websites as a creative director in a digital agency.

He is a prominent thought leader in the performance community and popular on the conference circuit where he evangelises the role of design in improving engagement with performance issues. Here is Mark's latest Velocity Conference talk on better performance through better design.

Mark Zeman


"SpeedCurve is visually awesome and holds functionality I've been expecting someone to finally build for quite a while."

Guy Podjarny - CTO Web BU, Akamai

"I'm a business leader not a web guru. SpeedCurve took 5 minutes to set up and gives me an instant view of how our site is performing in absolute terms, and relative to our competition. It helps me ensure we give our users the best possible experience."

Nick Howe - Vice President Learning and Collaboration, Hitachi Data Systems

"We used SpeedCurve to track the performance of the new Guardian responsive site which now loads four times faster than the previous version and is one of the fastest news sites in the US."


"We've got SpeedCurve on the studio wall monitor and staying faster than our competitors is hugely motivating."

Tom Dooner,