Path to Open Source

This document covers the development history of Actionbase before it was open-sourced. Future development will be tracked in public repositories.

MVP Phase

The MVP phase represents the entire period from project inception to open-source release. During this period, Actionbase was applied to various services and evolved through real-world use.

Phase 1: Foundation Building (2023)

Q: How do we validate technical feasibility and establish a foundation?

This period was invested to ensure a technical base that would support stable development in subsequent phases.

Key milestones:

Project kickoff and initial planning
Core design and implementation

AI used: GPT-4

Phase 2: Service Integration (Early 2024)

Q: How do we validate through real-world service deployment?

The system was safely integrated into production by maintaining the existing system, applying dual writes, and gradually migrating read functionality after sufficient validation.

Key activities:

First production service write/read migration: KakaoTalk Gift Wish

AI used: GPT-4

Phase 3: Stabilization (Late 2024)

Q: How do we stabilize the system and expand tenants?

Starting from a multi-tenant architecture, this phase introduced support for independent tenant configurations to ensure service isolation and enable isolated deployments.

Key improvements:

System stabilization and tenant expansion
Support for independent tenant configurations to isolate services
Operations automation and monitoring enhancement
Applied across commerce domain (e.g., KakaoTalk Gift Recent Views)

AI used: Claude 3.5 Sonnet

Phase 4: Building Sustainable Operations (Early 2025)

Q: How do we improve operational efficiency and address technical debt?

During this phase, Actionbase continued to be applied to various services while improving its operational foundation. Key efforts included reducing operational overhead, improving developer tooling, and addressing accumulated technical debt.

Key activities:

Applied across multiple domains (e.g., KakaoTalk Friends)

AI used: GPT-4o, Claude 3.5 Sonnet

Phase 5: Preparing for Open Source (2025)

Q: How do we prepare for open-source release while expanding adoption?

Building on the foundation from Phase 4, this phase focused on making Actionbase ready for open source. The reimplementation process led to the decision to open-source Actionbase. While legacy code remains, the reimplementation continues to progress toward a more maintainable codebase. During this period, Actionbase was broadly adopted across Kakao’s services.

Key changes:

Maintained API compatibility with existing systems
Redesigned API structure
Repository separation and organization
Separated internal and open-source areas

AI used: GPT-4o, Claude 3.5 Sonnet, Cursor

Open Source Release (January 2026)

After this MVP period, Actionbase was open-sourced in January 2026.

The codebase released is the same one that was developed, operated, and refined inside Kakao. Only minimal modifications were applied to remove security-sensitive or organization-specific details, and some internal features will be opened gradually as they are reviewed.

Why We Open-Sourced Actionbase

The same interaction features—likes, recent views, follows—were being rebuilt across teams, each time with different stacks, different schemas, different failure modes. And when traffic grew, each hit similar scaling walls.

Actionbase emerged as an attempt to stop solving the same problem ten different ways—and to solve it at scale.

Sharing a real journey

This codebase wasn’t designed for release. It grew through production incidents, shifting requirements, and years of real traffic. We chose to share it as-is—not a rewritten showcase, but the actual code that survived.

Outliving its creators

Internal systems often fade when their original maintainers move on. Open-sourcing creates a chance for the system to grow beyond any single team or company—shaped by those who actually use it.

Becoming part of something larger

Inside a company, an internal service is just another API to call. Developers designing new systems rarely adopt it as a core component, working with well-known technologies feels more valuable for their growth.

We understand this. By open-sourcing Actionbase, we hope it can become part of architectures we never imagined.

Acknowledgements

This work was supported by Kakao’s leaders and engineers, who helped the team build and operate the system.

Special appreciation goes to the HBase engineers at Kakao. Actionbase’s reliability benefits from the stability provided by HBase.

This release reflects the efforts of those who contributed to the system and the teams who supported its development. We look forward to continuing this project together with the open-source community.