2025-10 PyCon Brasil keynote - Behind the scenes of FastAPI and friends for developers and builders

Transcript

1. 🚀 Behind the scenes of FastAPI and friends for developers and builders
2. Who am I? Sebastián Ramírez tiangolo.com @tiangolo 󰎪➡󰎲 I created: Building:
3. @tiangolo
4. • Open source • Web APIs • Python framework @tiangolo
5. @tiangolo 84k+ ⭐ (now 90k+ ⭐)
6. @tiangolo 47K+ docs users 4M+ downloads
7. @tiangolo 47K+ docs users DAILY 4M+ downloads DAILY
8. @tiangolo 47K+ docs users DAILY 4M+ downloads DAILY
9. @tiangolo 110M+ downloads a month
10. @tiangolo 110M+ downloads a month > Germany's population
11. @tiangolo ⌚ 5K+ downloads since the start of the talk
12. Python Developer Survey @tiangolo
13. StackOverflow Developer Survey 2021 2025 @tiangolo
14. FastAPI stonks @tiangolo
15. Who uses FastAPI …and many more. @tiangolo
16. @tiangolo
17. Webb - Space Telescope Institute @tiangolo
18. OpenAI - ChatGPT @tiangolo
19. Simulate Galaxies @tiangolo
20. Accelerate particles at CERN - Large Hadron Collider @tiangolo
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22. 📜 Mini story @tiangolo
23. @tiangolo
24. @tiangolo
25. @tiangolo
26. @tiangolo
27. @tiangolo 󰳐 Academia
28. @tiangolo 󰳐 Academia
29. @tiangolo 󰳐 Academia
30. @tiangolo Kindergarten drop out 😅
31. @tiangolo • 🏠 Homeschool • 💻 Computers • 📹 Video edition • 🎹 Music production • 🎨 Graphic design • 🕸 Web development • 🤖 Systems for my parents' small business ◦ 😬 (which they didn't need) 🤓 Homeschool
32. @tiangolo
33. ... @tiangolo
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35. @tiangolo
36. ♻ Iterate @tiangolo
37. @tiangolo ♻ Iterate
38. @tiangolo ♻ Iterate
39. @tiangolo 💣 Complexity
40. 💣 Complexity @tiangolo
41. @tiangolo • For me • For my team • For the product • For everything... 󰞵 Solve a problem
42. @tiangolo • For me • For my team • For the product • For everything... 󰞵 Solve a problem
43. Innovation 🙄 @tiangolo 󰞵 Solve a problem
44. Innovation 🙄 @tiangolo ✨ Solve a problem ✨ 󰞵 Solve a problem
45. @tiangolo Power user first 🤓 󰞵 Solve a problem
46. @tiangolo • 🤓 Solve a technical problem • 🙋 A problem important to you • 📖 Study the tools • 👷 Sometimes no courses, only manuals, docs • ✨ SOLVE A PROBLEM ✨ 󰞵 Solve a problem - power user first 🤓
47. @tiangolo 󰞵 Solve a problem • ✨ Solve a problem • ✨ Solve a problem • ✨ SOLVE A PROBLEM ✨
48. ✨ Tips for building a product @tiangolo
49. @tiangolo ⚙ Build what needs to be built • ✨ Solve a problem • 🔍 Not solved yet? • ↩ Previous problem? • 🧱 Use other building blocks, open source • 🥞 Current abstraction layer too low? • ✏ Cost of learning much lower? • 🍒 Convenience much higher?
50. @tiangolo ⚙ Build what needs to be built • ✨ Solve a problem • 🔍 Not solved yet? • ↩ Previous problem? • 🧱 Use other building blocks, open source • 🥞 Current abstraction layer too low? • ✏ Cost of learning much lower? • 🍒 Convenience much higher?
51. @tiangolo ⚙ Build what needs to be built • 🥞 Current abstraction layer too low? • ✏ Cost of learning much lower? • 🍒 Convenience much higher? ⚖ Tip the scale ✨ Trip the scale ✨
52. • 🥞 Current abstraction layer too low? • ✏ Cost of learning much lower? • 🍒 Convenience much higher? @tiangolo ⚙ Build what needs to be built ⚖ Tip the scale ✨ Trip the scale ✨
53. @tiangolo 🐥 Optimize for user, not maintainer • 🥽 Point of view of user • 🏗 Design UX first, build internals to fit it • 🍕 Autocompletion depends on types • 📣 Inline errors depend on types • 📑 Explicit parameters, not **kwargs
54. @tiangolo 🐥 Optimize for user, not maintainer • 🥽 Point of view of user • 🏗 Design UX first, build internals to fit it • 🍕 Autocompletion depends on types • 📣 Inline errors depend on types • 📑 Explicit parameters, not **kwargs
55. @tiangolo 🐥 Optimize for user, not maintainer • 🥽 Point of view of user • 🏗 Design UX first, build internals to fit it • 🍕 Autocompletion depends on types • 📣 Inline errors depend on types • 📑 Explicit parameters, not **kwargs
56. @tiangolo 👔 Standards • 😴 Reading might be boring • 🔀 Free interoperability • 😱 Be aware of non-used standards • 👀 Be aware of standards de facto
57. @tiangolo 🐣 Capture a smart newbie • 🌱 Fresh eyes, nothing is obvious yet • 🕳 Find voids of info • 🥽 Adopt a newbie's point of view
58. @tiangolo 💥 Computer Science hard problems • ➖ Cache invalidation • 📢 Naming things
59. @tiangolo ➖ Reduce info duplication (cache invalidation) • 🐑 Not the same as code duplication • 🔧 Variables, configs • 🪞 Information duplication is a "cache"
60. @tiangolo ➖ Reduce info duplication (cache invalidation) • 🐑 Not the same as code duplication • 🔧 Variables, configs • 🪞 Information duplication is a "cache"
61. @tiangolo ➖ Reduce info duplication (cache invalidation) • 🐑 Not the same as code duplication • 🔧 Variables, configs • 🪞 Information duplication is a "cache"
62. @tiangolo ➖ Reduce info duplication (cache invalidation) • 🐑 Not the same as code duplication • 🔧 Variables, configs • 🪞 Information duplication is a "cache"
63. @tiangolo ➖ Reduce info duplication (cache invalidation) • 🐑 Not the same as code duplication • 🔧 Variables, configs • 🪞 Information duplication is a "cache" • 🍝 If duplication needed, keep it close • 🔄 Reduce out of sync
64. @tiangolo ➖ Reduce info duplication (cache invalidation) • 🐑 Not the same as code duplication • 🔧 Variables, configs • 🪞 Information duplication is a "cache" • 🍝 If duplication needed, keep it close • 🔄 Reduce out of sync
65. @tiangolo ➕ Reduce ambiguity (naming things) • 🐑 Avoid different things with the same name • 📝 In code, docs, configs
66. @tiangolo ➕ Reduce ambiguity (naming things) • 🐑 Avoid different things with the same name • 📝 In code, docs, configs
67. @tiangolo ➕ Reduce ambiguity (naming things) • 🐑 Avoid different things with the same name • 📝 In code, docs, configs
68. @tiangolo ➕ Reduce ambiguity (naming things) • 🐑 Avoid different things with the same name • 📝 In code, docs, configs
69. @tiangolo 📝 Write good docs - 1/2 • ↩ What needs to be explained before? • 🕸 Graph of concepts • 📖 Explain everything • 📝 Re-read, re-write, clean, trim down • 🐑 Reduce duplication of concepts • 🚲 User's minimum effort • 🚀 …to get maximum value
70. @tiangolo 📝 Write good docs - 2/2 • 💅 Space, graphics, emojis, notes • 📑 Consistency for terms and concepts • ✒ Style for terms and concepts • 👷 Enable power users • ✏ Docs driven development • ✅ Test example code in docs
71. @tiangolo 📝 Write good docs - 2/2 • 💅 Space, graphics, emojis, notes • 📑 Consistency for terms and concepts • ✒ Style for terms and concepts • 👷 Enable power users • ✏ Docs driven development • ✅ Test example code in docs
72. @tiangolo 🏰 Premature abstraction is dangerous • 🚤 Premature optimization • 🏰 Premature abstraction • 🥞 Reduce constraints and abstraction layers ◦ A class ◦ that calls another class' method ◦ when it could be a function • 👔 Harder to detect, looks engineery • ☑ Should have a reason
73. @tiangolo 🧬 Optimize evolution, not architecture • ♻ Better being able to refactor • 👔 …than pristine first architecture • 🪟 Types ◦ Mainly inputs and outputs of functions ◦ dataclass / Pydantic fields • ✅ Tests • ⛔ Limit ◦ Magic kwargs ◦ Import strings ◦ Magic strings
74. @tiangolo 🫓 Simple is better than complex • 🐍 Zen of Python • 🥵 Achieving simple is harder than complex • 🏰 "Building complex is easier" • 💪 Put the effort, build the simpler stuff • 😎 That's the price of cool products
75. 🏯 Tips for managing a large project @tiangolo
76. @tiangolo 📎 Workload • 🙋 Open source by one or two developers • 🫂 Community is made of specific individuals • 🤖 Automate
77. @tiangolo 📎 Workload
78. @tiangolo 🌐 FastAPI in Portuguese
79. @tiangolo 🌐 FastAPI in Portuguese
80. @tiangolo 🔖 Issues • 🐤 > 90% is user errors • 🐛 If allowed, declared as bugs • 📎 Not enough info • 📃 Use templates for questions / issues
81. @tiangolo 🔖 Issues
82. @tiangolo 🐶 Drive by PRs • 📂 Many files • 🌿 Multiple features at the same time • ⛔ Tests failing • 🫙 No tests covering the feature • 🎯 No clear objective • 🙋 No use case • 🧭 Out of scope • 🔮 PRs vs future plans • 🐶🎂 Cake vs Puppy PR — Will McGugan
83. @tiangolo 🔬 Drive by reviews • 💅 About style • 🙋 Code structure with personal opinions • ➕ Asking for extra changes or features • 🌳 One line change / 1000 lines to review • 📝 Docs with what to review • 🎯 Solves the problem? • ✅ Has tests?
84. @tiangolo 🏋 Yes gain, yes pain • 🐘 The bigger the impact ◦ ...the higher the chance of bitter people ◦ ...weirder the haters ◦ ...weirder complains • 🤷 That's success • 🌑 Dark places ◦ HackerNews ◦ Reddit ◦ Some Forums
85. @tiangolo 🏋 Yes gain, yes pain
86. @tiangolo 🏋 Yes gain, yes pain • 🤷 That's success
87. @tiangolo 🏋 Yes gain, yes pain • ☕ (I do drink lots of coffee) • 🎁 Your attention is valuable • 🏆 Reward your attention carefully • 👀 Brings visibility / importance
88. @tiangolo 🗯 Feedback
89. @tiangolo 🎭 Culture • 🫅 Don't convince entitled annoying people • 👹 Keep toxic people away • 🦖 Bad ones fall on their own • 🛡 Protect the community • ⚔ Take action when needed • 🌿 Most people are good • 🏗 Just build things • ✨ Solve a problem
90. @tiangolo 🗯 Feedback
91. @tiangolo 🏦 Sustainability • 🤝 Sponsors are friendly • 🍫 Small sponsorships make you happy • 🥗 ...but don't sustain • 💰 Sizable, recurrent sponsorships are rare • 📦 Mainly receiving something extra in exchange • 🫙 ...it's a transaction, you're selling something • 📺 Open source becomes distribution, marketing
92. 🚍🎟 Bus ticket factor @tiangolo
93. @tiangolo 🚌 Bus factor • 🚌 "what happens in case X get hit by a bus" • 🙋 One or two open source developers ◦ …the case for most projects ◦ …even the biggest ones • 🐸 Worrying about poisonous frogs • 🪥 …vs washing your teeth
94. @tiangolo 🚌 Bus factor • 🚌 "what happens in case X get hit by a bus" • 🙋 One or two open source developers ◦ …the case for most projects ◦ …even the biggest ones • 🐸 Worrying about poisonous frogs • 🪥 …vs washing your teeth
95. @tiangolo 🚍🎟 Bus ticket factor • 💰 Who's paying for the ticket • 🎟 What is the bus ticket • ✈ Airplanes have only 2 pilots ◦ 🎫 …lots of tickets • 🪙 Some value / objective ◦ 😌 Satisfaction ◦ 🏆 Recognition / job perks ◦ 🫙 Sell something
96. 🚍 Bus factor @tiangolo 🚍🎟 Bus ticket factor
97. 😎 Next problem to solve - shameless plug @tiangolo
98. @tiangolo
99. @tiangolo 🛳 Cloud Native Landscape
100. 💣 Complexity @tiangolo
101. @tiangolo You code. We cloud.
102. @tiangolo ✨ Solve a problem ✨
103. @tiangolo
104. Thank you! Sebastián Ramírez tiangolo.com fastapi.tiangolo.com @tiangolo