Endpoint documentation structure in Rest API - Step-by-Step Execution

Concept Flow - Endpoint documentation structure

Start

↓

Define Endpoint URL

↓

Specify HTTP Method

↓

Describe Purpose

↓

List Request Parameters

↓

Show Request Example

↓

List Response Fields

↓

Show Response Example

↓

Add Error Codes

↓

End

This flow shows the steps to write clear API endpoint documentation from URL to errors.

Execution Sample

Rest API

GET /users/{id}
Description: Get user info
Parameters: id (path, required)
Response: 200 OK with user data
Errors: 404 if user not found

This example documents a GET endpoint to fetch user info by ID.

Execution Table

Step	Section	Action	Details
1	Define Endpoint URL	Set URL pattern	/users/{id}
2	Specify HTTP Method	Choose method	GET
3	Describe Purpose	Explain what it does	Get user info by ID
4	List Request Parameters	Detail parameters	id (path, required)
5	Show Request Example	Provide example	GET /users/123
6	List Response Fields	Describe response data	User object with id, name, email
7	Show Response Example	Provide example	{ "id": 123, "name": "Alice", "email": "[e-mail]" }
8	Add Error Codes	List possible errors	404 if user not found
9	End	Finish documentation	Complete endpoint doc

💡 All sections completed to fully document the endpoint.

Variable Tracker

Section	Content
Endpoint URL	/users/{id}
HTTP Method	GET
Purpose	Get user info by ID
Request Parameters	id (path, required)
Request Example	GET /users/123
Response Fields	User object with id, name, email
Response Example	{ "id": 123, "name": "Alice", "email": "[e-mail]" }
Error Codes	404 if user not found

Key Moments - 3 Insights

Why do we specify HTTP method separately from the URL?

Because the same URL can support different actions like GET or POST, so specifying method clarifies what the endpoint does (see execution_table step 2).

What is the purpose of showing request and response examples?

Examples help users understand how to call the endpoint and what data to expect, making the documentation practical (see execution_table steps 5 and 7).

Why list error codes in endpoint documentation?

To inform users what errors might happen and how to handle them, improving robustness (see execution_table step 8).

Visual Quiz - 3 Questions

Look at the execution table, what HTTP method is used for the endpoint?

A PUT

B POST

C GET

D DELETE

💡 Hint

Check step 2 in the execution_table where HTTP Method is specified.

At which step do we provide an example of the response data?

A Step 4

B Step 7

C Step 5

D Step 8

💡 Hint

Look for the step labeled 'Show Response Example' in the execution_table.

If the endpoint had no errors to document, which step would be skipped?

A Step 8

B Step 6

C Step 3

D Step 9

💡 Hint

Step 8 is about adding error codes, see execution_table.

Concept Snapshot

Endpoint documentation structure:
- Define URL and HTTP method
- Describe purpose clearly
- List request parameters
- Show request and response examples
- Include response fields
- Add error codes if any
This helps users understand and use the API endpoint correctly.

Full Transcript

Endpoint documentation structure guides writing clear API docs. Start by defining the endpoint URL and HTTP method. Then describe what the endpoint does. List all request parameters with details. Provide examples of requests and responses to show usage. Describe response fields so users know what data to expect. Finally, add error codes to inform users about possible failures. This step-by-step approach ensures the documentation is complete and easy to follow.

Practice

1. What is the main purpose of endpoint documentation in a REST API?

easy

A. To explain how to use each API URL including methods and parameters

B. To store user data securely

C. To improve the speed of the API server

D. To design the user interface of a website

Solution

1. Step 1: Understand the role of endpoint documentation

   Endpoint documentation describes how to use each API URL, including methods and parameters.

2. Step 2: Compare options with this role

   Only To explain how to use each API URL including methods and parameters matches this purpose; others describe unrelated tasks.

3. Final Answer:

   To explain how to use each API URL including methods and parameters -> Option A

4. Quick Check:

   Endpoint documentation = Usage guide [OK]

Hint: Think: What helps users understand API URLs? [OK]

Common Mistakes:

• Confusing documentation with data storage
• Mixing API documentation with UI design
• Assuming documentation improves server speed

2. Which of the following is the correct way to document the HTTP method in an endpoint documentation?

easy

A. "method": "GET"

B. "method" = GET

C. method: GET;

D. GET

Solution

1. Step 1: Identify proper JSON syntax for documentation

   Endpoint docs often use JSON or similar formats; key-value pairs use colon and quotes for strings.

2. Step 2: Check each option's syntax

   "method": "GET" uses correct JSON syntax with quotes and colon; others use invalid or non-standard syntax.

3. Final Answer:

   "method": "GET" -> Option A

4. Quick Check:

   JSON key-value = colon + quotes [OK]

Hint: Remember JSON syntax: key in quotes, colon, value in quotes [OK]

Common Mistakes:

• Using equal sign instead of colon
• Omitting quotes around strings
• Using XML tags instead of JSON

3. Given this endpoint documentation snippet:

{
  "endpoint": "/users/{id}",
  "method": "GET",
  "parameters": {
    "id": "integer"
  },
  "response": {
    "200": "User object",
    "404": "Not Found"
  }
}

What is the expected response if the user ID does not exist?

medium

A. User object with empty fields

B. 404 Not Found error

C. 200 OK with error message

D. 500 Internal Server Error

Solution

1. Step 1: Read the response codes in the documentation

   The response section shows "404": "Not Found" which means if the user ID is missing, a 404 error is returned.

2. Step 2: Match the scenario to the response code

   Since the user ID does not exist, the API returns 404 Not Found, not 200 or 500.

3. Final Answer:

   404 Not Found error -> Option B

4. Quick Check:

   Missing resource = 404 Not Found [OK]

Hint: 404 means resource not found, check response codes [OK]

Common Mistakes:

• Assuming 200 OK always returns
• Confusing 404 with 500 server error
• Expecting empty user object instead of error

4. You see this endpoint documentation snippet:

{
  "endpoint": "/items",
  "method": "POST",
  "parameters": {
    "name": "string",
    "quantity": "integer"
  },
  "response": {
    "201": "Item created"
  }
}

But the API returns a 400 error when you send the request. What is the most likely mistake in the documentation?

medium

A. The endpoint URL is missing a trailing slash

B. The HTTP method should be GET, not POST

C. Parameters should be inside a "requestBody" section, not "parameters"

D. The response code 201 is incorrect for creation

Solution

1. Step 1: Understand POST request structure

   POST requests usually send data in the request body, not as URL parameters.

2. Step 2: Check documentation structure

   Parameters listed under "parameters" implies URL/query parameters; for POST data, it should be under "requestBody".

3. Final Answer:

   Parameters should be inside a "requestBody" section, not "parameters" -> Option C

4. Quick Check:

   POST data = requestBody, not parameters [OK]

Hint: POST data goes in requestBody, not parameters [OK]

Common Mistakes:

• Confusing query parameters with request body
• Changing HTTP method incorrectly
• Ignoring correct response codes

5. You want to document an endpoint that updates a user's email. It uses PATCH method at /users/{id}. The request body must include email as a string. The response returns 200 with updated user data or 400 if email is invalid. Which is the best way to structure this documentation snippet?

hard

A. {
"endpoint": "/users/{id}",
"method": "PATCH",
"parameters": {
"id": "integer",
"email": "string"
},
"response": {
"200": "Updated user object",
"400": "Invalid email error"
}
}

B. {
"endpoint": "/users",
"method": "PATCH",
"parameters": {
"email": "string"
},
"response": {
"200": "Updated user object",
"400": "Invalid email error"
}
}

C. {
"endpoint": "/users/{id}",
"method": "POST",
"parameters": {
"id": "integer",
"email": "string"
},
"response": {
"200": "Updated user object",
"400": "Invalid email error"
}
}

D. {
"endpoint": "/users/{id}",
"method": "PATCH",
"parameters": {
"id": "integer"
},
"requestBody": {
"email": "string"
},
"response": {
"200": "Updated user object",
"400": "Invalid email error"
}
}

Solution

1. Step 1: Identify correct HTTP method and endpoint

   The method is PATCH and endpoint includes user ID as a path parameter "/users/{id}".

2. Step 2: Separate path parameters and request body

   "id" is a path parameter, so it goes under "parameters"; "email" is sent in request body, so it belongs in "requestBody".

3. Step 3: Check response codes and descriptions

   Response codes 200 and 400 with correct descriptions match the scenario.

4. Final Answer:

   { "endpoint": "/users/{id}", "method": "PATCH", "parameters": { "id": "integer" }, "requestBody": { "email": "string" }, "response": { "200": "Updated user object", "400": "Invalid email error" } } -> Option D

5. Quick Check:

   Path params + requestBody + responses = { "endpoint": "/users/{id}", "method": "PATCH", "parameters": { "id": "integer" }, "requestBody": { "email": "string" }, "response": { "200": "Updated user object", "400": "Invalid email error" } } [OK]

Hint: Put path params in parameters, data in requestBody [OK]

Common Mistakes:

• Putting request body fields in parameters
• Using wrong HTTP method
• Omitting requestBody section