Design and Evolution of a Scalable Multi‑Tenant Platform for JD's Activity Building System

Background: Tongtian Tower is a JD activity‑building platform offering rich templates for web and mobile, supporting module construction, custom H5 development, and RN development, with a single build synchronizing to app, PC, and various mini‑programs.

Challenges: Rapid business expansion introduced many independent sites (main site, international sites, commercial sites, etc.), leading to high hardware and maintenance costs, code duplication, linear growth in development complexity, and poor extensibility.

Solution Overview: The backend team devised a scalable, high‑availability, maintainable, flexibly deployable, multi‑tenant architecture to address these issues.

DDD Adoption: To resolve the monolithic SOA’s bloated service layer, arbitrary file assembly, and technology‑driven layering, the team applied Domain‑Driven Design (DDD) to define bounded contexts, aligning business and code models.

Diamond Symmetry Architecture: Inspired by hexagonal and layered architectures, this pattern places the domain at the core, separating internal domain models from external gateways, forming a clear internal‑external layered structure that guides context collaboration.

PaaS Transformation: The team introduced a platform‑as‑a‑service approach, defining business identities (horizontal vs. vertical), structuring requirements, exposing extension points, and allowing third‑party developers to co‑create domain capabilities.

Common Version Construction: Core shared functions were extracted into a common codebase, while site‑specific features were packaged as sub‑modules and managed via Maven. SPI + configuration decoupled middleware, enabling logical (tenant) isolation without physical resource duplication.

iPaaS and Open Co‑creation: A one‑stop iPaaS solution (JD Retail Front‑End R&D Standard) was launched, offering five capabilities—design front‑end collaboration, front‑end standardization, template sharing, capability aggregation, and intelligent quality monitoring—to accelerate building complete marketing operation systems across sites.

Example: The ihub.jd.com platform enables developers to create cross‑platform floor templates (H5, iOS, Android) that can be consumed by merchants and operators when built‑in templates are insufficient.

Capability Aggregation: Lambda functions extend services for stateless tasks such as request wrapping, field filtering, and image processing, enabling rapid delivery without full application redeployment.

Middleware Decoupling: SPI combined with configuration files provides flexible middleware switching and minimal code changes, improving safety and adaptability.

One‑Click Deployment Solution: The JD Retail Cloud Delivery Platform allows developers to request resources, manage application versions, and deploy new sites with a single configuration, achieving “once configured, everywhere deployed”.

Results: New independent sites now launch in about 1.5 months (down from ~4 months), a speedup of over 70 %, freeing developers to focus on business logic rather than repetitive setup.

Future Direction – Cloud Native: To quickly port the platform to public, private, or hybrid clouds, a cloud‑native design is proposed, leveraging observability, high availability, fault tolerance, self‑healing, and zero‑trust principles.

Author Team: Platform R&D – Zhang Qin, Fang Zhengdong, Zhu Zhiguo.