Principles of Awesome APIs and How to Build Them.

Transcript

1. Principles of Awesome APIs
   and How to Build Them.
   Keavy McMinn, Fastly
   RubyConf 2019
   @keavy
   

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5. Try to work with the wind, don't fight
   it all the time.
   

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6. Consistent.
   Stable.
   Well-documented.
   

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7. APIs: Our experience as
   consumers
   

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8. APIs: Our experience as
   producers
   

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9. APIs: Our experience as producers
   Fixing it would actually
   break it.
   

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10. APIs: Our experience as
    producers
    

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11. Application Programming
    Interface
    

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13. APIs = Constraints
    

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14. Work with the constraints.
    

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15. Remember these constraints are
    good for us too.
    

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19. Consistent
    

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20. Consistent
    Consistent data
    

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21. ✅
    {
    "admin": true
    }
    ❌
    {
    "admin": "1"
    }
    

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22. API Descriptions
    — JSON Schema
    — Open API (formerly Swagger)
    — RAML
    — APIs.json
    — API Blueprint
    — Postman Collections
    — Async API
    

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23. Consistent
    Have one source of truth.
    

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24. Have one source of truth.
    JSON Schema
    

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25. JSON Schema
    committee gem
    https://github.com/interagent/committee
    

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26. JSON Schema
    PRMD gem
    https://github.com/interagent/prmd
    

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27. JSON Schema
    Online examples
    http://bit.ly/heroku-schema
    

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28. It will be amaaazing!
    

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29. Consistent
    Monitor your
    inconsistencies.
    

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30. Monitor your inconsistencies.
    Compare what you say and
    what you do.
    

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31. Monitor your inconsistencies.
    Try a portion of your API
    

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32. Monitor your inconsistencies.
    Technical deep dive
    

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33. Monitor your inconsistencies.
    Technical deep dive
    https://github.com/whitequark/parser
    

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34. # Get a dog.
    get "/dogs/:dog_id" do
    authorize_access :users, :bots
    # finds the dog
    # renders the dog as JSON
    end
    

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35. Then it will be amaaazing!
    

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36. Stable
    

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37. Stable
    Invest in upfront design.
    

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38. Invest in upfront design.
    — What will users do with it?
    — What does your business need from it?
    — What does it look like?
    — What will you call it?
    

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39. Remember:
    puppies APIs are
    for life not just for
    Christmas!
    https://www.flickr.com/photos/27587002@N07/5170590074
    

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40. Design while the cost of
    change is low.
    

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41. Stable
    A calm space.
    

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42. metoffice.gov.uk
    

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43. Stable
    

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44. Change itself is not necessarily
    bad.
    Negative impact from change is
    bad.
    

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45. Minimize the negative
    impact
    

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46. Well-documented
    

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47. Well-documented
    Inform users about
    everything, early and often
    

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48. Well-documented
    Then remember that people
    don’t read.
    

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49. Well-documented
    Enable a holistic view.
    — Endpoints that are undocumented
    — Endpoints that are in any special phase
    — Anything to be deprecated
    — Dates
    

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50. Well-documented
    Governance
    

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51. Well-documented
    Shared understanding is easier
    when it’s all written down.
    

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52. Well-documented
    Internal guides
    

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53. Well-documented
    API Styleguide
    

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54. API Styleguide
    Avoid verbs and adjectives
    ❌
    GET /pets/most-recent
    ✅
    GET /pets?sort=date-added
    

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55. API Styleguide
    Make exceptions deliberately
    GET /repos/:owner/:repo/releases/latest
    

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56. Well-documented
    Internal guides
    

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57. Well-documented
    Who is responsible for
    what?
    

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58. Well-documented
    Who gets a say in decision
    making?
    

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59. It doesn’t have to be fucking hard.
    It just has to be consistent.
    Which is fucking hard.
    — Brett Sutton, Triathlon coach
    

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60. Good luck!
    Thank you,
    @keavy
    

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