How Rexan Wong Built Apps With Over 500K Users Before He Turned 18
Meet Rexan Wong, a self-taught coder from Hong Kong, who has built and scaled a number of apps to 500,000+ users.
Early Days
Wong attended the Christian Alliance International School and the Hong Kong International School, graduating in 2025.
He taught himself to code in 2023, learning through YouTube.
Prior to creating his own apps, Wong became deeply involved in the blockchain space, interning at CryptoBLK and Arta TechFin and working on research for smart contracts and blockchains.
He became a Thirdweb Ambassador, the youngest person to hold this position, and lectured on cryptography and blockchains for City University of Hong Kong's Gifted Education Programme for teenagers.
Wong was also heavily involved in hackathons, winning the Apple Swift Student Challenge, one of 300 global winners selected from over 10,000 students, and was a finalist at ETHGlobal Online, while traveling to Canada for ETHGlobal Waterloo.
He also participated in a Developer DAO and Mina Protocol hackathon, creating a privacy-preserving protest application and winning first place among 40 teams. Rexan also won the Hong Kong Blockchain Olympiad in 2024.
Wong transitioned from coding in blockchain-related applications to building consumer apps in 2024. His most important project so far was Text Behind Image.
Building Text Behind Image
In October 2024, Wong built textbehindimage.com, a free tool that lets anyone put text behind images. He was inspired by content creator and entrepreneur Daniel Dalen.
He built it in three hours using Cursor.
It crossed 300,000 users, pulled in 3 million views on X, and hit #1 Product of the Day on Product Hunt. Ryan Hoover, the founder of Product Hunt, gave it a shoutout too.
More Apps, And More Users
Rexan kept building apps after Text Behind Image.
Around the same time, he shipped videofast.gg, a video editor he worked on between schoolwork. It landed #2 Product of the Day on Product Hunt and built up 500 regular users.
In 2025, he built bulletpen.ai, an app that turns spoken thoughts into polished writing in real time. It grew to 2,000 active users and $1,000 in monthly recurring revenue.
Then came brandthetics.com, a tool for turning raw talking videos into cinematic short-form content, styled after creators like @bymaximise.
Put together, his content apps crossed 500,000 users worldwide. Text Behind Image was the biggest.
His Business Side
In 2025, Wong became a portfolio founder at 24Labs, a studio that builds, scales, and acquires software companies.
There, he built make.ad, an AI tool that turns a single product photo into a finished ad.
Make.ad hit close to 5,000 users and $5,000 in monthly recurring revenue within its first month live.
What He's Doing Today
Rexan is now based in San Francisco.
He is building software for consumer brands and marketing teams as part of Founders Inc's Artifact Program. In June 2026, he also became a founding member of a new group called The Collective.