Stable at 500x the Load. A Fifth of the Bill.

Over 500x

concurrent users

−80%

hosting bill

1 month

from takeover to stable

Talk to the Operators

Sector: Music Fan Club Platform
Engagement: Platform Rescue and Takeover
Roles: Interim CTO, Head of Engineering
Dates: Mid-2024 to today

The Situation

Chorus's fan club platform fell over every time its biggest artist went live. SIROC took over engineering and had it stable within a month.

held at once before the platform fell over: ~20 users
knew how payments worked: 1 person
a month on hosting, and still rising: ~€10k

Chorus runs paid fan clubs for music artists, white-label on web and mobile. SIROC came in to build its native iOS and Android apps, against an API the in-house team owned.

Then Chorus signed a multi-Grammy-winning American artist, the biggest on the platform by far. The artist's first livestream took the API and the web down, and so did every big moment after it. The web held ~20 users at once. Payments ran in the frontend and failed under load, and 1 person knew how they worked.

Tickets piled up and the artist was ready to leave. Meanwhile the hosting bill had reached ~€10,000 a month and was still rising.

The SIROC team around a table of laptops, with the Chorus app up on the wall screen.

What We Did

Diagnosed before spending.
The CEO asked SIROC for advice. The in-house plan was 4 bullet points and bigger servers. The diagnosis was different: a database exhausted by unoptimized queries fired straight from the frontend, which no amount of hardware would fix.
4 bullet points the in-house plan to fix scaling
Took the CTO seat.
In November 2025 the CEO asked SIROC to take over engineering. A SIROC partner became Interim CTO, alternating weeks between Madrid and Los Angeles, with a SIROC engineer running the code.
Nov 2025 SIROC took over engineering
Fixed the root cause.
The problem was never server size. It was how the app asked the database for data. We fixed that in the existing code, with no rewrite, because the artist was close to leaving.
0 rewrites fixed inside the existing platform
Sized the infrastructure to the work.
The database was ~50x bigger than the work it did. Right-sizing it, and trimming the services around it, brought the monthly hosting bill down to a fraction of what it was.
~€8k a month saved on hosting, an 80% cut
Restored payment integrity.
An untested migration had left fan subscriptions corrupted across 2 platforms. SIROC wrote the recovery plan and brought them back into one state in 2 weeks.
2 weeks to bring every fan subscription back in order

Before vs After

Each metric before and after the engagement, with the change between them.
Concurrent users held	After: 10,000+ Before: ~20	Change: Over 500x
Monthly hosting bill	After: ~€2,000 Before: ~€10,000	Change: −80%
Platform stability	After: 99.8% uptime Before: Down under load	Change: Stable
Mobile apps	After: iOS and Android Before: No apps	Change: Shipped
Artists pitched a year	After: 72 Before: 8 to 9	Change: 8x

Where They Are Today

~40k subscribers

across more than 30 artists

The biggest artists now run livestreams and post to their communities without outages. Once the assets arrive, a new artist goes live on web and mobile in a couple of hours. Chorus carries ~40k subscribers across more than 30 artists.

When we arrived ~20 users held at once before the platform fell over

What SIROC Brought

We were hired to build apps and ended up running engineering. When the in-house answer was more servers, we took the Interim CTO seat and fixed the platform in the code itself.

“We care about one thing: execution, clarity and delivery.”

Joan Martin, Head of Engineering, SIROC

The same team designed and built the white-label app family, 5 iOS apps from one codebase plus native Android. A sales prototype for a new artist went from 6 to 8 hours of work to about two. SIROC also holds equity in Chorus, so the platform staying up is our problem too.