ChordNote is a platform delivering chord charts and sheet music online for five instruments including guitar, bass, piano and ukulele. With 500,000+ songs and 10M+ monthly users, it is one of the largest of its kind in Japan, bringing the joy of playing to a great many musicians.
「Pages stop under heavy load·Copyright managed by hand·Billing web-only — that was the old foundation, and An eight-month rebuild with zero downtime, the story of a transformation into a next-generation foundation that withstands heavy traffic and unifies multi-channel billing.
The music content distributor operates ChordNote, an online service delivering chord charts and sheet music for guitar, bass, piano, ukulele and more. From artist and song search through chord display to favourites and history, it supports a player's urge to pick up an instrument in one place.
Alongside free use, revenue comes from premium membership — ad-free with every feature unlocked — billed on the web or in-app. The CMS handles song registration as well as copyright data from bodies such as JASRAC and NexTone: a model that supports both content and rights.
These were not technical problems but Management issues tied directly to retention, revenue and competitiveness. The more traffic arrived, the less stable the service became, and delays in rights processing held back how fast songs could be published.
Data reads reached their limit whenever traffic spiked, so At peak, pages slowed or stopped. This drove users away and cost opportunities.
Work data from JASRAC and NexTone was cross-checked by hand, so Days to register. The speed of publishing new songs was the business bottleneck.
Billing ran on the web alone, so Missed billing opportunities from app users. This held back revenue.
Display worked differently for guitar, bass, piano and ukulele, so Maintenance costs climbed. Improvements struggled to reach every instrument.
Working with Amela, the music content distributor rebuilt its foundation without ever taking the service offline: reads distributed to withstand heavy load, copyright processing automated, web and app billing unified, and chord display for five instruments consolidated into a single engine. The zero-downtime migration left users none the wiser while giving the business fresh capacity.
PHP (public site)
React
Tailwind
Laravel
PHP
JWT
Stripe
Apple IAP
MySQL (master/slave read replicas)
Redis（queue）
AWS
Google Pub/Sub
Sentry
YouTube API
The rebuild paid off in four directions: user experience, operational efficiency, availability and revenue. A service that never stops sustains retention, automation speeds up song delivery, and multi-channel billing closes the revenue gaps.
It no longer stalls under traffic spikes, so users can open a chord chart comfortably at any time.
Automatic import of copyright data cut the lead time to publish a song dramatically.
Web and app channels are unified so every user has a path to subscribe.
Lower operational load and steadier revenue freed up capacity to invest in new features and new instruments.