Inputs & Outputs

Handle path parameters, query strings, request bodies, and configure API responses.

Inputs & Outputs

Your endpoints receive data from requests and send back responses. Define the inputs an endpoint expects, attach a function, then use those values from the function steps.

The endpoint editor showing input and output configuration
Configure inputs and outputs in the endpoint editor

Inputs

When a request arrives, Spala makes the data available through built-in variables:

Path parameters (params)

Dynamic segments in the URL path:

// Endpoint: GET /api/cases/:id
// Request:  GET /api/cases/42

params.id // "42"

Query string (query)

Key-value pairs after the ? in the URL:

// Request: GET /api/cases?page=2&limit=10

query.page   // "2"
query.limit  // "10"

Good to know

Query string and path parameter values are always strings. Convert them with query.page | toNumber when you need a number.

Request body (input)

The JSON body for POST, PUT, and PATCH requests:

// Request: POST /api/cases
// Body: { "case_name": "Contract Review", "status": "open" }

input.case_name  // "Contract Review"
input.status     // "open"

Headers (headers)

HTTP headers sent with the request:

headers.authorization    // "Bearer eyJhbG..."
headers['content-type']  // "application/json"

File inputs

For upload endpoints, add a file input in the endpoint editor and use the generated input in the attached function. This keeps the Playground, generated docs, and implementation in sync.

Outputs

Use a Return step in your function to set the response:

// Return data with a 200 status
Value:  vars.cases
Status: 200

// Return an error with a 404 status
Value:  { error: "Case not found" }
Status: 404

// Return a created resource with 201
Value:  vars.newCase
Status: 201

Common status codes

| Code | Meaning          | When to use                        |
|------|------------------|------------------------------------|
| 200  | OK               | Successful read or update          |
| 201  | Created          | Successfully created a resource    |
| 400  | Bad Request      | Missing or invalid input           |
| 401  | Unauthorized     | Missing or bad authentication      |
| 404  | Not Found        | Resource does not exist            |
| 500  | Server Error     | Something went wrong               |

Create an Endpoint
/endpoints/creating-endpoints
Set up your endpoints
API Docs
/features/api-docs
Share endpoint inputs and responses
Protect Your Endpoints
/endpoints/authentication
Add authentication