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API Specification Template

This is a template for how API endpoints should be documented and defined. This section would include a high level description of what the API is used for and why someone would use it. You should also specify anything here that is common to all endpoints, i.e. content type, common body elements, ect...

When writing specifications, you only need to include sections that are relevant to each endpoint. For example, if your endpoint didn't have any route parameters then you would not include a section for route parameters.

Any route parameters that should appear in an endpoint should be written with a colon in front of it, path/:param1/path/:param2.

You do not need to specify any kind of 5XX type responses in a specification, 5XX level messages should never be returned in a production API.

Notes About Ordering

  • The routes defined in the API should be defined with top level routes first and then sub-routes, i.e. /animal before /animal/dog.
  • For any route with multiple methods or same level routes with similar functionality, define GET then POST then PUT.
  • In response definitions define all 2XX responses before any 4XX.

Structure of Endpoint Specification

METHOD /path/:of/route

A short description of what this route is used for and what it does.

Route Parameters

path_parameter_1: PARAMETER_TYPE
  • What this path parameter is used for and what it represents
path_parameter_2: PARAMETER_TYPE
  • ...

Query Parameters

query_parameter_1: PARAMETER_TYPE
  • What this query parameter is used for and how it changes the request.

Request Body

{
  "FIELD0": "Making a request",
  "FIELD1": STRING,
  "FIELD2": [
    {
      "ARRAY_FIELD1": INTEGER,
      "ARRAY_FIELD2": WEIRD_TYPE1
    },
    ...
  ],
  "FIELD3": WEIRD_TYPE2
}

Any non-standard type has to be explained here or in the common section if the type is used in many requests.

  • A WEIRD_TYPE1 is an INTEGER between -4 and 5 inclusive.
  • A WEIRD_TYPE2 is an array of even size in the following form:
    [
      INTEGER,
      STRING,
      ...
    ]
    

Responses

XXX Status Code Message

A quick description of what this response means and why it might've been displayed.

{
  "FIELD0": "YES",
  "FIELD1": INTEGER
}

XXX Status Code Message

.....

Example Note API

This is an example of an API for a basic note service that can get, create and update notes. All request and response bodies will be of type JSON and include an appropriate Content-Type: application/json header.

GET /api/note

Used for getting one or all of the notes in the database.

Query Parameters

note_id: INTEGER
  • Get a note that has this specific ID.

Responses

200 OK

Every thing is okay.

If there were any potentially confusing fields in the response body you would explain what they mean and what they're for here.

{
  "status": "OK",
  "notes": [
    {
      "id": INTEGER,
      "title": STRING,
      "content": STRING,
      "date": DATE
    },
    ...
  ]
}

Any non standard data types that you use in your body specification you would specify here. For types that are used in multiple endpoints, consider adding their definitions as a section at the top of the document.

A DATE is a String in the format: "MM-DD-YYYY HH:MM:ss"

400 BAD REQUEST

This happens if the client sends a request that does not conform to the standard outlined above.

{
  "status": "BAD REQUEST",
  "reason": STRING
}

POST /api/note

Used for creating one or more notes to be stored in the database.

Request Body

{
  "notes": [
    {
      "title": STRING,
      "content": STRING
    },
    ...
  ]
}

Responses

200 OK

The notes were successfully created.

{
  "status": "OK"
}

400 BAD REQUEST

The request body was malformed according to the specification.

{
  "status": "BAD REQUEST",
  "reason": STRING
}