Internal technical demonstration
Light-Convert Cloud — WeChat Mini-Program File-to-PDF Toolkit
Light-Convert Cloud is a WeChat mini-program for converting Word, Excel, PowerPoint, images and Markdown to PDF, plus merging, splitting and editing PDF pages — all inside WeChat, no app install required.
Technology stack
- WeChat Mini Program
- TDesign
- Astro
- NestJS
- TypeScript
- Prisma
- MySQL
- Redis
- BullMQ
- Docker
- Gotenberg
- OSS
Challenge
Students submitting assignments, office staff archiving and printing documents, and developers or writers exporting Markdown all need file conversion without installing software or manually tracking when temporary files expire.
Approach
The mini-program client submits a conversion job to a NestJS API, which queues the work through Redis and BullMQ to a Dockerized Gotenberg renderer and stores the result in object storage behind a link that expires automatically and cleans itself up.
Architecture
A native WeChat mini-program built with TDesign, paired with an Astro-built marketing portal, calls a NestJS + TypeScript + Prisma + MySQL backend; conversion jobs flow through a Redis/BullMQ queue to Gotenberg workers, with results held in OSS on a TTL.
Outcome
Live with a free daily quota and paid 'advanced processing coupons' for large files and advanced features; converted files are typically retained for 24 hours before automatic deletion.