Request Path Variables - Atrahasis Guide

Vars Tab

The Vars tab manages path variables—dynamic segments in your URL path that get replaced with actual values before the request is sent. Path variables are identified by the colon prefix in the URL (e.g., :userId).

What Are Path Variables?

Path variables are placeholders within the URL path that represent dynamic values. Unlike query parameters, they are part of the path itself, not appended after a question mark.

URL Structure

URL with path variables:

https://api.example.com/users/:userId/posts/:postId

After variable replacement:

https://api.example.com/users/123/posts/456

Syntax: Path variables must start with a colon (:) followed by the variable name. Valid names contain letters, numbers, and underscores.Port numbers excluded: All-numeric names (e.g., :8082 in http://localhost:8082/users/:id) are treated as port numbers, not path variables. Only names containing at least one non-digit character are detected, so :id appears in the Vars table but :8082 does not.

Variable Table

The Vars tab displays a table where each row represents one path variable.

Column	Description
Checkbox	Enable or disable the variable. When disabled, the `:varName` is removed from the URL.
Key	The variable name (without the colon). Changes here update the URL automatically.
Value	The value that replaces the variable when the request is sent.
Delete (X)	Removes the variable from both the table and the URL.

Automatic Variable Detection

Atrahasis automatically detects path variables in your URL and populates the Vars tab.

How It Works

Type a URL containing :variableName in the URL input
The Vars tab automatically creates rows for detected variables
Enter values for each variable in the table
When sent, variables are replaced with their values

Sync Behavior

Adding a variable to the URL creates a new row in Vars
Renaming a variable key updates the URL
Deleting a row removes the variable from the URL
Disabling a variable removes it from the URL (but keeps it in the table)

Required Variables Warning

Path variables must have values before sending. If you try to send a request with empty path variables, Atrahasis redirects you to the Vars tab with a warning.

Please set values for the required path variables before sending the request.

This prevents sending malformed URLs like /users/:userId to the server, which would result in a 404 or routing error.

Adding Variables Manually

You can add variables manually using the "Add Variable" button. When you add a variable and give it a key, the URL is updated to include /:key at the end.

Example

Before: https://api.example.com/users

Add variable "id":

After: https://api.example.com/users/:id

Using Environment Variables as Values

Path variable values can reference environment variables. This is useful for IDs that change between environments.

Example

Key	Value
userId	{{testUserId}}
orderId	{{lastOrderId}}

Environment variables are resolved before replacing path variables, so the final URL contains the actual values.

Common Patterns

Single Resource

/users/:userId

Get, update, or delete a specific user by ID.

Nested Resources

/users/:userId/posts/:postId/comments/:commentId

Access resources that belong to other resources in a hierarchy.

Action Endpoints

/orders/:orderId/cancel

Perform an action on a specific resource.

Version and Tenant

/api/:version/tenants/:tenantId/users

Multi-tenant APIs with versioning in the path.

Vars vs Params Comparison

Aspect	Vars (Path Variables)	Params (Query Parameters)
Location	In the URL path	After the ? in URL
Syntax	:variableName	?key=value
Required	Usually yes (identifies a resource)	Usually optional (filters, pagination)
Purpose	Resource identification	Filtering, sorting, configuration
Example	/users/123	/users?page=1

Params Headers