Robert Axle Project FitFinder API v1


Welcome to the Robert Axle Project FitFinder API documentation. The FitFinder API is a powerful tool designed to help you seamlessly integrate bicycle fitment finder functionality into your applications. FitFinder API specializes in identifying suitable Robert Axle thru axles for a vast array of bike models and configurations.

Base URL

The API is hosted with Amazon Web Services and available at:


To access the FitFinder API, a client ID is required. The client ID serves as your application's unique identifier and API key. To obtain a client ID, please get in touch with [email protected].

Testing Authentication

You can make a test request using the provided client ID to verify that your client and authentication are working correctly. For example:

GET [BASE_URL]/client-class?client_id=YOUR_CLIENT_ID

Replace YOUR_CLIENT_ID with the client ID assigned to your application. A true response from the API indicates that your account is active.

Select-Options-Client Endpoint

The select-options-client endpoint facilitates the sequential input of customizable options for the Thru Axle Fit Finder, guiding users through the selection process for optimal bike fit. This sequential input accepts and returns values for "attachment," "type," "ebike," "brand," "hub," and "model." The endpoint is meticulously designed to provide responses tailored to individual clients' unique specifications and preferences at each stage of the fit finder.

POST [BASE_URL]/API/select-options-client

Request Data

The select-options-client endpoint requires data in the form of a JSON object containing the current_selections parameter. The parameter uses a specific delimiter system for sequential input. Here's an example of how you should structure the request data:


  • Trim all whitespace from posting values. E.g. 'Front Rack' -> 'FrontRack'
  • Prepend the value string with your client ID followed by an underscore, pipe, and underscore. E.G. 12345_|_
  • For each category (e.g., "attachment," "type," etc.), use three underscores (___) to separate the choices.

Here's a complete example of a full SKU request:


Order, Selections, and Definitions

Order Selection Definition
1 Client ID Unique identifier assigned to your application by the API.
2 Attachment What users want to attach to the bike (e.g., Kid Trailer, Front Rack, Training).
3 Type The type of bike component (e.g., Rigid Fork, Suspension Fork).
4 Ebike Indicates whether the bike is an electric bike (Yes/No).
5 Brand The brand of the bike (e.g., All City, Trek).
6 Hub The hub specification of the bike (e.g., 12x100).
7 Model The model of the bike (e.g., Super Professional).

Building a Fit Finder (Request -> Response)