Erlang is a language optimized for exactly our context. Concurrent, distributed, high-volume systems.

Erlang manages millions of processes efficiently by bypassing the operating system kernel and handling concurrency entirely within the BEAM virtual machine. Unlike heavy OS threads, Erlang processes are lightweight (starting at ~300 bytes), fully isolated, and utilize their own independent stacks, heaps, and message mailboxes.

https://medium.com/@sonampatel_97163/how-erlang-handles-millions-of-processes-without-breaking-a-sweat-4f92344d5bef

Erlang achieves this massive scale through several core architectural principles:

Ultra-Low Memory Footprint Erlang processes do not start with megabytes of reserved space. A newly spawned process only takes a few hundred bytes of memory. Stacks and heaps are dynamically allocated, growing and shrinking as needed, which means millions of idle connections (like WebSockets or IoT sessions) consume almost zero memory.

https://stackoverflow.com/questions/2708033/technically-why-are-processes-in-erlang-more-efficient-than-os-threads

No Shared Memory or Global Locks Processes do not share state. Because there is no shared memory, there is no need for complex, bug-prone locking mechanisms (like mutexes) to prevent race conditions. Processes communicate exclusively via asynchronous message passing, acting like isolated actors.

https://medium.com/@sonampatel_97163/how-erlang-handles-millions-of-processes-without-breaking-a-sweat-4f92344d5befhttps://medium.com/@sonampatel_97163/how-erlang-handles-millions-of-processes-without-breaking-a-sweat-4f92344d5bef

Isolated Garbage Collection Since every process has its own memory heap, garbage collection is localized. When an Erlang process dies, its entire memory is instantly reclaimed by the VM, meaning no global, stop-the-world garbage collection pauses will disrupt the entire system.

https://medium.com/@kanishks772/memory-management-in-beam-why-erlang-never-runs-out-b35087af3612

Cooperative Preemptive Scheduling Instead of relying on the Operating System to manage CPU context switching, the BEAM VM uses its own custom schedulers—typically launching one per CPU core. These schedulers do not measure context switches in time, but rather in reductions (abstract units of work representing function calls). Every process gets a fair slice of reductions, after which it is swapped out, ensuring no single process monopolizes a core.

https://www.reddit.com/r/erlang/comments/1e5sxc2/how_does_erlang_manage_to_support_so_many_light/https://www.reddit.com/r/erlang/comments/1e5sxc2/how_does_erlang_manage_to_support_so_many_light/

Efficient I/O Handling I/O operations (such as network requests or file reads) do not block the VM. Behind the scenes, the BEAM offloads I/O polling to the operating system and only wakes up the Erlang process once the data is ready to be read, ensuring the CPU spends its cycles actively running processes rather than waiting on slow hardware.

https://www.reddit.com/r/erlang/comments/4sogzb/how_do_erlang_microprocesses_work_internally/