OpenAPI without the pain
A 142-minute course on writing clean, reusable, easy-to-maintain OpenAPI specifications. The guide Daniel Alfocea wishes he'd had when he started writing APIs. Taught in Spanish.
With Daniel Alfocea
- of video
- 142 min
- videos
- 21
- level
- beginner
In Spanish. This program is taught in Spanish: its videos, exercises and exam are in Spanish. This page is a translation to help you decide.
Who it is for
Developers and architects who want to stop suffering with API documentation, and frontend and backend teams that need a clear contract. No previous OpenAPI knowledge needed.
About the program
Writing OpenAPI without fighting it
142 minutes of video on writing OpenAPI specifications that are clear, reusable and easy to maintain.
Language: the course is taught in Spanish. The videos, the slides and the exam are in Spanish. This page is the English description only.
Hardly anyone hates documenting APIs. What they hate is doing it without anyone having shown them how.
And it shows:
- Chaotic specifications.
- Duplicated endpoints.
- Schemas that look nothing alike.
- Endless arguments between frontend and backend.
All of it ends the same way: production errors and lost time.
The first step to fixing it is to have a good OpenAPI.
Who is telling you this
I’m Daniel Alfocea (or cr0hn, whichever you prefer). I’ve spent twenty years in development and security.
I spent 5 years as a lead engineer on one of the products at 42Crunch, a UK company specialized in API security.
I made this course for one reason: it’s the guide I wish I’d had when I started writing APIs.
What you get
First, what a specification is and why you need it, before writing a single line.
Then how to define data properly: the request body, data types and the structures you’ll use most.
You learn not to repeat yourself. Reusable components, inheritance between schemas and organization with tags, so the specification doesn’t grow by copy and paste.
One module is about validation: data validation as your first line of defense, to stop bad input before it reaches the backend.
Also examples, extensions for what the specification doesn’t cover, and a handful of tricks that save time and errors.
And you finish with generators. How to get the specification out of FastAPI and Spring Boot without making a mess of it, which open source tools generate one for you, and an all-in-one tool, Capture.
I want to write better specifications
Who it’s for
It’s for you if:
- You’re a developer or architect and want to stop suffering with documentation.
- You have to maintain legacy APIs and don’t know where to start.
- You work on a team where frontend and backend don’t understand each other.
- You want to use OpenAPI to improve quality, security and communication.
What it costs
€99, one payment, and the course is yours. If I update it, you get the new version without paying again.
It is not a course on security or on API design in general. It’s about writing the specification well. If you already write it with reusable schemas, validations and examples, module 2 will tell you little that’s new and you’ll go straight to the generators and the bonus.
Cheers,
Dani
P.S. If you’re unsure, watch the open lesson first. In under 7 minutes you’ll know if it’s for you.
Syllabus
142 minutes of video in 21 lessons, plus an exam and the slides, spread over 6 modules. The ones marked “Sample” can be watched without logging in.
01¿De qué va esto? 1 lesson · about 7 min
- Qué es una especificación y para qué narices la necesito 6:37
02Escribiendo OpenAPIs Sin Dolor 14 lessons · about 100 min
- Definición de datos y demás yerbas
- Request Body: cómo definir correctamente los datos de entrada
- Tipos de datos: estructuras comunes y cómo usarlas en OpenAPI
- Componentes (I): definición y reutilización básica
- Componentes (II): enlaces entre operaciones con Links
- Componentes (III): gestión de eventos con Callbacks
- Componentes (IV): organización de la documentación con Tags
- Validación de datos: tu primera línea de defensa
- Herencia en OpenAPI: reutiliza y extiende definiciones sin repetir
- Extensiones en OpenAPI: añade lo que la especificación no cubre
- Ejemplos en OpenAPI: muestra claramente lo que esperas recibir y enviar
- Trucos útiles en OpenAPI: atajos que te ahorran tiempo y errores
- OpenAPI: cosas útiles que no sabías que podías hacer
- Buenas y malas prácticas en OpenAPI: lo que deberías (y no deberías) hacer
03Auto-Generadores de OpenAPIs y cómo ahorrarte parte del trabajo 5 lessons · about 24 min
- Empezar desde 0 es muy tedioso
- Usa bien los frameworks y FastAPI
- A Spring Boot también hay que darle cariño
- Generando automáticamente con herramientas OpenSource
- El todo en uno: Capture
04Checkpoint final 1 lesson
- Examen de certificación
05Transparencias 1 lesson
- Transparencias del curso
06BONUS 1 lesson · about 10 min
- Bonus 1 - Los 5 errores más comunes al escribir OpenAPIs (y cómo evitarlos)
Sample lessons
Watch them before you pay.
-
Qué es una especificación y para qué narices la necesito6:37
Who teaches it
Daniel Alfocea
Twenty years in development and security, and author of tools such as GoLismero, Plecost and Dockerscan.
Questions
Do I need to know OpenAPI before I start?
No. You start from zero, and the basic concepts are explained before moving on to real examples.
You only need to know what an API is and want to do things properly.
Do I see code, or is it just theory?
Is it useful if I already use Swagger?
Does it work for my language or framework?
Yes. OpenAPI doesn’t depend on the language, so what you learn applies equally to Python, Java, Go or Node.
There is a module with FastAPI and Spring Boot to see how they generate the specification for you, and how not to spoil it.
Is there a certificate?
Are 142 minutes worth €99?
If they save you one long argument between frontend and backend about what an endpoint returns, they’re well on their way to paying for themselves.
And if you’re not sure, watch the open lesson first. It’s under 7 minutes and costs nothing.
Who it is forDevelopers and architects who want to stop suffering with API documentation, and frontend and backend teams that need a clear contract. No previous OpenAPI knowledge needed.