The Story of Building a REST API Data Mocking Tool ⚡

In the financial industry, it is difficult to use real data directly due to regulatory compliance, making sophisticated data processing essential for testing. In particular, since multiple external institutions and servers are linked together to produce a single API response, testing a specific scenario requires going through multiple stages such as the client, server, and core banking, resulting in high communication costs.

To solve this, after reviewing existing alternatives such as writing UI test code, hardcoding within code, and using a Proxy Server, the team decided to directly develop a REST API mocking tool. Referencing the open-source Chucker, they implemented functionality to check and edit API requests and responses.

The in-house developed mocking tool Zeus was designed based on the following goals:

• Ensuring mocking reliability through consistent data
• Convenient UX accessible by anyone, anywhere
• Simple mocking procedures including saving API lists, changing responses, and delay functionality

Through this, not only client developers but also planners and QA personnel can now easily control the data they need and proceed with development and testing regardless of the external environment.