API first is not always the best approach and should not be imposed on development teams. It prioritizes APIs over other concerns. A better approach is to start with data modeling and understand consumer needs to develop API interfaces. Interface first involves starting with a data model, describing API interfaces programmatically around that model, and integrating data engineering steps into the API development process. This helps ensure APIs are consumer-centric and focused on the underlying data.

1. API first … not!
1

2. codecentric AG
HoherWall 15
44137 Dortmund
Telefon:+49 (0) 151. 10 86 70 74
Daniel Kocot
Head of API Experience & Operations
AsyncAPI Ambassador
daniel.kocot@codecentric.de
www.codecentric.de
Innovative- Trustful - Competent - Pragmatic
2

3. API first
3

4. API first is about prioritising APIs
within an organisation
4

5. APIs become a main part of the
business model of the organisation
5

6. API first is not a paradigm for your
development team!
6

7. Developmen
t teams
7

8. Three dimensions of API Development
8
DESIGN FIRST CODE FIRST PROTOTYPE
FIRST

9. API as a medium
of transport for
data
9

10. API development is just only about
deploying a service together with an
API
10

11. But what about data?
11

12. API are not
the panacea
12

13. APIs are not the panacea
13
In some
situations they
are not the
best fit
Security
Dependencies Complexity

14. Understand
the consumer
needs
14

15. Understand the consumer needs
15
Data in transit Trigger functions

16. Two sides of
a medal
become one
16

17. Awareness of Data Products and
Data Contracts
17

18. Only good Data Products can lead to
API Products of the same value
18

19. Data contracts as foundation
19

20. Derive data models from data
contracts
20

21. DataOps
21

22. Automate all the things
22

23. Focus on
Developer
Success
23

24. Developer don’t want to tackle YAML
or JSON files
24

25. They should just be artefacts driven
by automated process
25

26. Code first based on the data model
26

27. Code first based on the data model
27
SPECIFIC
DEVELOPMENT STACK
GOVERNED
DEVELOPMENT
PROCESS
DOCUMENTED AND
GUIDED DEVELOPMENT
PROCESS

28. Interface first
28

29. Interface first
29
Describe endpoints as agnostic
interfaces with Design first approach
Possibility to cover all output ports of
a Data Product in one Interface
description

30. Interface First Tooling
30
Mircosoft TypeSpec TaxiLang

31. Microsoft TypeSpec
31

32. Microsoft TypeSpec
32

33. TaxiLang
33

34. TaxiLang
34

35. Interface first at a glimpse
35
Starting data model backed by a data product and data
contracts
Describe the interfaces for model programmatically and
type-safe
Available solutions so far: Microsoft TypeSpec and
TaxiLang
Need to extend API Operations pipeline with Data
Engineering steps

36. Conclusion
36

37. Conclusion
37
Don’t talk about API first with development
teams
Honor the skills of the development teams and
have trust in them
Guide them towards consumer centricity and the
idea of Interface first

38. References
38
• Cover Slide: Photo by Dim Hou on Unsplash
• Slide 3: Photo by Kai Wenzel on Unsplash
• Slide 12: Photo by Tengyart on Unsplash
• Slide 16: Photo by Berend van Rossum on Unsplash
• Slide 23: Photo by Guille Álvarez on Unsplash

39. 39
codecentric AG | Hochstraße 11 | 42697 Solingen
Creating the digital future together.
Thank you!