The first version of Senden started taking shape back in 2023. It was an early prototype built on a plain MariaDB database and a plain express backend architecture. The stack would not have scaled well, and the project was put on pause while we gathered more experience building production systems.
In mid 2025, Senden's lead developer, wireway.ch, resumed work on the project. This time with years of additional experience in scalable backends, distributed systems, and privacy first infrastructure. Rather than patch the old version, Senden was rebuilt from the ground up using modern, industry standard tooling designed for global deployment, efficient caching, and scalability.
Enterprise grade code quality checks are in place across every part of the stack, from the backend API to the web client.
Senden is built around three principles: privacy, minimality, and efficiency.
Fair question. If a service is free and the business model isn't selling your data, something has to give.
During the beta phase, we measured the average infrastructure cost per active user to be around €0.007 per user per month. Less than a cent. Senden is architected to be extremely efficient, which keeps that number low. Those costs are covered by donations. There are no investors, no analytics brokers, and no data sales funding the service.
Senden will stay donation funded. There is no paid plan, and donating raises no limits . We would rather ask people who can afford it to chip in than split the product into a good version and a worse one.
Further down the line, users will be able to host their own backend nodes and voice servers. This gives privacy minded users full control over where their data lives, and it also takes load off the central infrastructure, which helps Senden stay sustainable as it grows.
A 3rd party security audit by an external firm is pending, and its report will be published in full. Privacy claims are only as trustworthy as the scrutiny behind them, and we want that scrutiny to be public.
Senden has been load tested with 750'000 simulated concurrent active users and confirmed to handle that traffic smoothly. The result confirms that the infrastructure is ready for Senden to grow without compromising on the performance or privacy guarantees the project was built around.