Elements of API Excellence Jeremiah Lee 2014-10-31T11:00+11:00 • 

Elements of API Excellence Jeremiah Lee 2014-10-31T11:00+11:00 

#DX #WD14 @JeremiahLee 

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ThatsNotHowGearsWork.tumblr.com 

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unintentionally 

selfishly 

blindly 

intentionally 

holistically 

Empathy
as an
Applied Science 

understand anticipate share feelings 

research in order to solve problems 

Empathy
as an
Applied Science 

Graph by Dave Corby (2010) based on Guide to the Software Engineering Body of Knowledge (SWEBOK) by IEEE Computer Society (2004) Customer Requirements Requirements Specification Functional Specification Design Specification Validation Review Verification Study the requirements Clarify the requirements Write the 
 software Test the 
 software Validate against requirements Review with
 customer Define new requirements Software Development Life Cycle 

Based on Aarron Walter’s Designing For Emotion FUNCTIONAL 

FUNCTIONAL RELIABLE Availability (uptime) Scalability (load, response time) Stability (consistency) Security Based on Aarron Walter’s Designing For Emotion 

RELIABLE FUNCTIONAL USABLE Intuitability Testability Corrective Guidance Based on Aarron Walter’s Designing For Emotion 

PLEASURABLE USABLE RELIABLE FUNCTIONAL Based on Aarron Walter’s Designing For Emotion 

Customer Requirements Requirements Specification Functional Specification Design Specification Validation Review Verification Study the requirements Clarify the requirements Write the 
 software Test the 
 software Validate against requirements Review with
 customer Define new requirements Software Development Life Cycle PLEASURABLE USABLE RELIABLE FUNCTIONAL 

Today, let’s talk about… 1. Personas 2. Passive usability testing with data 3. Active usability testing with real, live people 

Personas • Are descriptive representations of the people who use your product and the context they operate in • They make assumptions about users visible • They provide a frame of reference for your team • Validate with user interviews and surveys 

Persona Context • Relationship with product • Platform, programming language • Experience / skill level • English proficiency • Motivation • Resources • Role in the organization 

Who are my users? BENNETT
 backend web developer, prefers Java, CS degree from UC Davis, full time developer, advocated to use our product RACHEL web designer/developer, prefers JavaScript/Node, no degree but strong developer, had no input on using our product JANE
 iOS developer, "unicorn" designer and developer, self-taught, moonlighting on her own projects, makes recommendations 
 on products ANDY
 self-proclaimed geek, comes from IT background, likes to script things together using Python, hobbyist hacker 

Passive Usability Testing • Examine support requests • When are they asking for help? • Frequently asked questions • Frequently misunderstood concepts • Frequently hit errors 

Passive Usability Testing • Examine support requests • API usage during an integration • How long between app registration and first request? • What are the first requests and first errors? • How long before going to production? 

Passive Usability Testing • Examine support requests • API usage during an integration • API usage after an integration • Detect based on IP address, user auth, requests increase • What endpoints are being used? How are they used? • Anti-pattern detection based on request volume or type 

Active Usability Testing • Existing APIs: “Dumb Pair Programmer” • With a user you trust in their natural environment • Silently observe as they work: • Interactions with team: how do they talk about you? • How do you fit into their application? • How does the user approach the integration with you? • What problems do they encounter? • How do they test the integration? 

Active Usability Testing • Existing APIs: “Dumb Pair Programmer” • New APIs: Throw-away prototypes • Create a mock API: just enough functionality to be used • Document it: reference docs, just enough conceptual info • Create a well defined project ready for an integration • Hire an outsider who doesn’t have insider assumptions • Have user record screen, face, voice with Silverback • Have user commit to Git at regular interval 

Active Usability Testing • Existing APIs: “Dumb Pair Programmer” • New APIs: Throw-away prototypes • Analyze the data for moments of emotional response • Happy • Sad • Confident • Frustrated • Confused 

Active Usability Testing • Existing APIs: “Dumb Pair Programmer” • New APIs: Throw-away prototypes • Analyze the data for moments of emotional response • How long did it take to accomplish tasks? • What worked? What didn’t work? • How can the good things be more affirming? • How can the bad things be prevented? • How can the situation be corrected better? 

The secret to
machines talking to machines
is to speak human first. 

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