Performance Newsletter RESOURCES # Prevent third-party scripts from crippling speed
As developers, we frequently use third-party tooling coming in the form of external scripts. Unfortunately, often those trackers and widgets can significantly slow down our apps and websites.

Luckily, [Ryan Townsend](https://twitter.com/ryantownsend) wrote an impactful, nine-step guide to mitigating potential harmful effects, featuring such strategies as asynchronous inclusion or preload. Thanks, Ryan! ⚡️

[How 3rd Party Scripts can be performant citizens on the web](https://www.twnsnd.com/posts/performant_third_party_scripts.html)

NEWS # The cost of mobile ads on news websites

Folks over at The New York Times sat down to examine the performance and cost footprint of ads in top 50 news outlets. Guess what they found out—**more than half of transferred data comes from advertising and has a hefty price tag.**

For the biggest offender, [Boston.com](https://www.boston.com/), visiting the home page every day for a month would cost the equivalent of about $9.50 in data usage just for the ads! No need to say that neglecting performance can be pricey for our users.

[The Cost of Mobile Ads on 50 News Websites](https://www.nytimes.com/interactive/2015/10/01/business/cost-of-mobile-ads.html?smid=tw-share)

RESOURCES # Comprehensive guide on image optimization

[Addy Osmani](https://twitter.com/addyosmani) is back with what’s probably the most extensive eBook on image optimization 😱  From choosing an image format, image spriting, lazy-loading to automation, CDNs, preloading and performance budgets specific to imagery. 

An absolute must-read for anyone building for the Web, wanting to use media sensibly. 

[Essential Image Optimization](https://images.guide/)

RESOURCES # Actionable book on web font performance

[Bram Stein](https://twitter.com/bram_stein), one of the few highly regarded web font experts, just published a comprehensive handbook under A Book Apart.

If you’ve ever wondered how to efficiently utilise web fonts and more importantly, avoid common performance pitfalls, this highly practical book is a gold mine.

[Webfont Handbook](https://webfonthandbook.com/)

BROWSER KNOWLEDGE # Network Information API landed in Chrome
Network Information API, a specification developed by [Ilya Grigorik](https://twitter.com/igrigorik), [Marcos Cáceres](https://twitter.com/marcosc) and [Fernando Jiménez](https://twitter.com/f_jimenez) Moreno is already accessible in Chrome M62. 

**navigator.connection **can help determine connection type (for example cellular, Wi-Fi, Ethernet or Bluetooth), bandwidth and round-trip estimates and much more. This API will hopefully aid developers in tailoring user experiences for slower connections.

[Network Information API in Chrome](https://twitter.com/igrigorik/status/911263826594619393)

TOOLS # Serving Typekit fonts without JavaScript
Typekit, one of the most popular web font services, is continuing their mission of enabling fast font delivery. It’s now possible to serve custom fonts without any script! 👏

It not only reduces the performance footprint but allows using the vast Typekit library in HTML emails, custom webpage builders and Google AMP. You can opt-in to test this feature via enabling [Early Access](https://pages.typekit.com/early-access-user-guides/en/early-access/). 

[Serve web fonts without JavaScript](https://blog.typekit.com/2017/08/30/css-font-loading/)

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