Fuego is an OpenAPI framework designed to facilitate seamless communication between API consumers and systems, emphasizing accuracy and ease of integration in Go. It offers features like automatic OpenAPI spec generation, centralized error handling, and quick documentation updates that improve the overall development experience. The framework is community-driven, garnering significant support and contributions while addressing common API challenges.

1. Fuego: an OpenAPI framework
Ewen QUIMERC’H Edouard LACOURT
go-fuego/fuego

2. Who are we?

3. A major issue working with APIs
API
Consumers (front,
other APIs, mobile
app…)
How can consumers and API systems exchange information seamlessly?
GET data
Bad request
Route does not exist
500 errors

4. OpenAPI!
REST API API users
Fully detailed interface contract
json/yaml description

5. OpenAPI: the good is the ugly
… but it’s unreadable
& unmaintainable for
humans 🤢
Everything is declared
& standardised …
❤️
=

6. Swagger UI as interactive documentation
🤩

7. Swagger UI, the OpenAPI for humans
REST API
Machines
Humans
Raw JSON/YAML spec
Swagger
Browser
Client Generators
❓

8. Server-side OpenAPI state of the art
1. Generate OpenAPI spec from
source code
2. Generate server code from existing
OpenAPI spec
Server code
boilerplate
interfaces

9. Code-first : better than Doc-first?
Faster Prototyping
Code agility > Specification burden
Ease of Use
Code familiar for developers > learn a
specification format.
Flexibility
Refactor code > Refactor yaml spec
Less Emphasis on Design
Tool Limitations

10. OpenAPI state of the art : mostly in dynamic languages
No Go code-first framework?
We should create one!
- Strong static typing
- Good performance
- Error as values
- Simplicity
❓

11. Introducing Fuego 🔥
100% accurate OpenAPI generation in Go
Using latest features of the Go programming
language (generics, built-in router…)

12. Fuego 🔥 features
Compatible with Go std lib (no lock-in) : Use any http.Handler middleware or handler! Fuego
also supports log/slog, context and html/template.
Serialization/Deserialization: Fuego automatically serializes and deserializes JSON, XML and
HTML Forms based on user-provided structs (or not, if you want to do it yourself)
Validation: simple validator based on go-playground/validator
Transformation: easily transform your data by implementing the fuego.InTransform and
fuego.OutTransform interfaces - also useful for custom validation
Error handling: Centralized error handling with the standard RFC 9457.
Rendering / content-negociation : Simple and fast rendering system based on
html/template - you can still also use your own template system like templ or gomponents

13. Introducing Fuego 🔥

14. Introducing Fuego 🔥

15. Integrating Fuego 🔥 in your workflow
Start-time Generation: never get out-of-date: when the server starts,
the documentation is updated
Expose the running API in non-prod envs
Opt-in On-demand generation: generate without
starting the server
Golden file target
Oasdiff - see the difference between the old spec
and the new one in HTML
LOCAL
ACROSS TEAMS

16. Demo Fuego 🔥
Fuego 🔥 Demo

17. What Open-Source brought us
- Sharing a minimal working version does not stop a
project from being exposed under the spotlight
- Project hype & fun : 900+ stars, 25 contributors, a lot of
kind comments & issues to improve the framework:
community is awesome
- Known in our company for being the Open-Source guys
- Talks & meetups! Don’t be shy, it works

18. Fuego: an OpenAPI framework
Thanks!
Ewen QUIMERC’H Edouard LACOURT
go-fuego/fuego