Do you know how many third-party scripts your pages are currently running? And do you know how many of those scripts are affecting your site's performance — either by slowing down page rendering or by potentially blocking the entire page? If you don't know the answer to these questions, you're not alone. The rampant proliferation of third-party scripts makes them difficult to manage and control. In this presentation, you'll walk through a process for testing the scripts on your pages to see which ones represent a SPOF. We'll also review an 11-step plan for bullet-proofing your site against third-party failure. For more on web performance and application delivery, please visit: http://blog.radware.com/applicationdelivery/applicationaccelerationoptimization/

1. Can Third-Party Scripts
Take Down Your
Entire Site?
Tammy Everts
O’Reilly Webcast – June 4, 2014

2. Conversions
Ad revenue
Page views
Visitor data
No need to re-invent the wheel
Quick and easy
Established
Support
Slide 2

3. Third-party calls can make up
>50% of page requests.
Slide 3
Steve Souders: http://www.fastly.com/blog/steve-souders-webperf-web-components/

4. Slide 4

5. Slide 5

6. Slide 6

7. Third-party scripts present risks to your pages
and to your users:
Outages
Slowdowns
Security (?)
Slide 7

8. Slide 8

9. Slide 9

10. Increase page weight
Increase number of hosts and connections
Introduce additional latency
Slide 10

11. Slide 11
832ms 1.788s918ms

12. Wait… what the heck is a
fourth-party call?
Slide 12

13. Slide 13
http://www.webperformancetoday.com/2011/07/14/fourth-party-calls-third-party-content/

14. Slide 14

15. 1. Audit your third-party scripts.

16. • Identify all third-party scripts
• Know which pages they’re on
• Find out what performance best
practices, if any, each script uses
(e.g., deferral, async loading)
• Read the SLA for each provider (if they
have one)
Slide 16

17. Slide 17
http://www.webpagetest.org

18. Slide 18

19. http://www.webperformancetoday.com/2014/03/18/waterfalls-101-how-to-use-a-waterfall-chart-to-diagnose-
performance-pains/
Slide 19

20. Slide 20

21. Slide 21

22. 2. Test for SPOFs.

23. The old, painful way:
http://www.webperformancetoday.com/2011/10/13/how-
vulnerable-is-your-site-to-third-party-failure/
Slide 23

24. Slide 24
The new, better way:
https://chrome.google.com/webstore/search/spof-o-matic

25. Slide 25

26. Slide 26

27. Slide 27

28. Slide 28
SPOF: 22.7s
Original: 3.5s

29. Slide 29

30. Slide 30

31. Slide 31

32. Slide 32

33. Slide 33
Original
SPOF

34. https://www.optimizely.com/security
Slide 34

35. Slide 35

36. Slide 36

37. Slide 37
Original
SPOF

38. Blackhole test results fall into one of three groups:
1. SPOF page loads SLOWER than original page
Fix: Deferral or async script
2. SPOF page loads FASTER than original page
Fix: Talk to provider about script hosting
3. SPOF page times out.
Fix: Same as #1
Slide 38

39. 3. Before you add a new script, research
the provider.

40. • Response time and time to last byte
• RT and TTLB from multiple locations
• Average monthly downtime
• Do they use a CDN?
• If so, where are their caches located?
Slide 40

41. 4. Read the provider’s
service level agreement.

42. An ideal third-party SLA should:
• Express monthly annual uptime guarantee as a percentage
(ideally, as close to 100% as possible)
• Explain how performance will be monitored and reported
• Describe the process for reimbursing site owners (if site owners
are paying for the service provided by the script) if uptime drops
below the SLA guarantee
Slide 42

43. 5. Perform a cost-benefit analysis.

44. Slide 44

45. Slide 45

46. 2-second slowdown = 14% conversion loss
But…
…if that same tool promises a 20% conversion increase,
that = a net gain of 6%
Slide 46

47. 6. Be ready to say no.

48. Slide 48

49. 7. Defer scripts whenever possible.

50. Slide 50

51. Pro: It’s a relatively easy fix.
Con: It won’t work for all content.
Slide 51

52. Slide 52

53. 8. Use asynchronous scripts.

54. Slide 54

55. Slide 55

56. Slide 56
Pro:
Doesn’t block primary content.
Cons:
Can be tricky to program.
Can mess up onLoad and make it difficult
to see other problems.

57. http://www.stevesouders.com/blog/2009/04/27/loading-scripts-without-blocking/
Slide 57

58. Slide 58
http://calendar.perfplanet.com/2011/the-art-and-craft-of-the-async-snippet/

59. 9. Monitor constantly.

60. RUM/APM
Tag management systems
SPOF-o-matic
No excuses.
Slide 60

61. 10. Give feedback to providers.

62. Slide 62

63. Slide 63

64. 11. Know when to pull the plug.

65. Slide 65

66. Tammy Everts
tammye@radware.com
webperformancetoday.com
twitter.com/tameverts
Slide 66
Questions?