1.
Developers are People Too!
Ronnie Mitra
@mitraman
rmitra@layer7tech.com

2.
Developers are People Too
User Experience
 We continually have experiences as we use products in our day to day lives. Theese experiences
can be both positive or negative and they shape the way we percieve the products that we that we
use.
 User Experience or UX based design invovles creating experiences that are positive for the user.
We can apply this idea to the world of APIs and gain a positive outcome.
 Of course in our world developers are our users, so we can be more specific and describe…
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3.
Developers are People Too
Developer Experience!
slide 13 of 142

4.
Developers are People Too
Ronnie Mitra
 I work for Layer 7
- A CA technologies company
- I am an API Architect in Layer 7’s API Academy
- I was born in Toronto, Canada (remove this line)
 I now live in London, England
slide 2 of 142

5.
Was that uncomfortable?
Why?

6.
Aesthetics

7.
Interaction

8.
Structure

9.
a poor experience overall

10.
regardless of the content

11.
An API Scenario….

12.
I want to add weather
forecast data to my
mobile app. An API
should help!
http://www.southparkstudios.co.uk/avatar

13.
I’m having trouble
finding an API that
does what I want.
http://www.southparkstudios.co.uk/avatar

14.
the registration process
is a nightmare!
http://www.southparkstudios.co.uk/avatar

15.
What is XML-RPC? I
don’t even have an
XML parser!
http://www.southparkstudios.co.uk/avatar

16.
http://www.southparkstudios.co.uk/avatar
Why is everything in
fahrenheit!?

17.
small annoyances add up
to create a poor experience

18.
designing an API is easy
effective API design is difficult

19.
effective == meeting our design and business goals

20.
Priority:
Lower Cost
Priority:
Increased Adoption

21.
http://www.flickr.com/photos/nirufe/3469696707
My API
Style?
XML? JSON?
Representations?
Resources?
Security?
Streaming?

22.
A user experience based approach can help

23.
Functionality
Usability
Experience

24.
Experience
Usability
Functionality

25.
What does the API do?
Where is it located?
How reliable is the implementation?

26.
The stereotypical SOA approach
Functionality focused
Everything is a service
Service catalog
Make people use it

27.
Experience
Functionality
Usability

28.
How do I use the API?
How easy is it for me to accomplish my own goals?
How much of my time do I need to commit?

29.
The API Revolution
Developer focused
Deployed in competitive markets

30.
Don’t forget:
Usefulness > Usability

31.
Functionality
Usability
Experience

32.
How does using the API make me feel?

33.
Developer Experience (DX):
1. the sum of interactions between the
developer and an API owner

34.
Developer Experience (DX):
1. the sum of interactions between the
developer and an API owner
2. the emotive impact of API usage on the developer

35.
Understanding API Interactions

36.
API
functionality

37.
Portal
API
usability

38.
API
experience
Portal

39.
API

40.
API

41.
who are our users?

42.
Josh
I blog, I tweet, I
code and I swear.
Age: 25
Occupation: Web/Mobile Developer
Technical Profile: 7 years experience,
hackathon champion, JavaScript and
objective-c expert. Hates XML.

43.
why are we always building APIs for Josh?

44.
Tony
I’m never leaving
this company.
Age: 45
Occupation: Enterprise Developer
Technical Profile: 27 years industry
experience, skilled in Java, VB, COBOL.
Knows the backend system better than
you do.

45.
You can’t design for usability if you don’t
know who is using your API

46.
Human Computer Interaction

47.
source: Brad A. Myers. "A Brief History of Human Computer Interaction Technology."
ACM interactions. Vol. 5, no. 2, March, 1998. pp. 44-54.

48.
Where is our Fitts’ Law?

49.
Are we just feeling around in the dark?

50.
We have lots of usability and UX guidance

51.
We have API usability theory and guidance

52.
Steven Clarke:
Describing and Measuring API Usability with the
Cognitive Dimensions
Abstraction level
Learning style
Working framework
Work-step unit
Progressive evaluation
Premature commitment
Penetrability
API elaboration
API viscosity
Consistency
Role expressiveness
Domain correspondence

53.
Usability Aspects of a Web API (a work in progress)
Task : Invocation Ratio
Structure
Navigation
Developer Stack Size
Time to First Call
Error Handling
Number of Decisions
Learnability
Vocabulary

54.
Task:Invocation Ratio
How many calls does it take for the developer to
accomplish their desired task?

55.
Structure
How deep is the required data located?
What is the signal to noise ratio?

56.
Navigation
How difficult is it to move from one result to another?
How difficult is it to locate a required datum?

57.
Developer Stack Size
how many new components are needed?

58.
Time to First Call
How quickly can a new user make their first API call?

59.
Errors
Where are they?
How difficult are they to fix?
What is the nature of the error? (unpredicted result,
invalid input, out of sequence, etc…)

60.
Vocabulary
How many new concepts, terms, labels or keywords must
be learned before an API can be successfully invoked.

61.
Experience Aspects of an API (a work in progress)
Engagement
Pleasure
Familiarity
Trust
Safety

62.
+ =

63.
Design the API
Establish Business
Goals
Identify Design Goals and
System Constraints
Identify Target Users
Define Interactions

64.
Prototype
Observe
Design
Design the API

65.
DX is not a feature

66.
understanding your audience is the key to
understanding their experience

67.
design APIs for people not machines

68.
API Management
virtual cloudon-premise

69.
Layer 7 Demonstration
Tomorrow
10:50
Katrinebergssalen
Want to see our products in action?

70.
Developers are People Too!
Ronnie Mitra
@mitraman
rmitra@layer7tech.com