What a Client Programmer Does at a Game Company

A client programmer isn't just someone who makes the game that appears on screen — they take on the role of making the game actually work by interlocking with planning, server, art, UIUX, effects, motion, and QA.

A 4th-year client programmer at Cookie Run: Kingdom uses the development flow of the minigame "Jumping Platform" as an example to unpack the order in which real work actually proceeds. Through the case of 'Jungle Warrior Cookie's Berry Berry High High!', updated on June 4, 2025, they show the entire process from content planning to post-launch management.

Work generally proceeds in the following flow.

• Content decision: The update direction is decided centered on the PD, story, and art, and minigame ideas connected to the story come out.
• High-level direction/detailed planning meeting: The experience and structural direction of the minigame are decided, and the client checks technical feasibility and scheduling.
• Kickoff meeting: Server, client, art, UIUX, effects, and motion together finalize the spec, and the client proactively proposes the direction for resource production as well.
• Data structure meeting: Decides how to design the Excel data shared by server and client.

Before development, tool development is also important. In this case, they built a map tool that generates map data randomly according to rules, and lets you visually check it in the Unity Editor and adjust platform positions and types. Automating repetitive work, reducing mistakes, and improving balancing and collaboration efficiency are the core value of the tool.

Once full-scale work begins, some tasks proceed in parallel by job function, and the client connects the results within the game.

• Data/server work: Once planning's placeholder data is uploaded, the server implements it, and the client connects to the server to confirm normal operation.
• Resource work: Art creates the resources, UIUX assembles a Prefab based on them, and then effects and motion add visual polish.
• Client work: All resources and data are attached to the actual game logic and implemented, and it's verified via video and captures that they're used as intended.

During work, communication among fellow client programmers is also important. To avoid duplicating implementation of features that already exist without knowing it, they first look for similar content cases and frequently ask each other questions and share structures.

In the wrap-up stage, resource management is key. Cookie Run: Kingdom uses Unity AssetBundle, and if build resources and bundle resources reference each other incorrectly, white square boxes can appear or bundle size can grow unnecessarily large. So they manage duplicates and errors using a tool that checks for external resource references.

Before and after launch, feedback meetings, QA, and build submission follow. QA tests on the editor and real devices based on inspections and TCs, and when issues come up, the client fixes them and rebuilds. Even after submission to the app store, live issue fixes, memory management, and refactoring continue.

In particular, for mobile games, supporting low-spec devices is important. On some devices, app memory may be limited to around 2GB, so in heavy sections like right before entering combat, unused resources need to be unloaded in advance to free up memory. Since small technical debt left unattended can grow into major failures, refactoring should be done continuously, including coordination with related departments and sharing with QA.

Skills recommended for new hires to prepare include data structures and algorithms, design patterns, Git, Unity Profiler / Memory Profiler, UniTask, and DOTween. On top of that, having launch experience or tool-building experience is a strength in terms of practical adaptability and portfolio.

Ultimately, a client programmer is the person who brings the game to life. Taking responsibility not just for coding but also for communication, problem-solving, collaboration, optimization, and post-launch management, they carry the entire process of completing the game through to the end together with the team.