Jan Čapek is a Czech engineer and Braiins co-founder with Pavel Moravec, associated with Braiins OS and the design of Stratum V2 alongside Moravec and Matt Corallo.
Braiins began as Jan Čapek and Pavel Moravec's shared company focused on embedded software. Marek Palatinus, known as Slush, founded the original Bitcoin.cz Mining Pool in 2010. Later ownership and operation of the pool do not change who originally created it. [Braiins — Remaining pool stake acquisition]
Braiins dates its acquisition of a majority stake and all operations to 2013. Its announcement of the remaining stake identifies 1 September 2020 as the transaction date, although the page shows publication on 29 December 2021. The page date is therefore not the acquisition date. [Braiins — Remaining pool stake acquisition]
The company's history credits Čapek's leadership with verifying AsicBoost on Antminer S9 and developing open-source Braiins OS, launched in 2018. This concerns software controlling the mining device, not a claim that Čapek designed the S9 chip itself. [Braiins — Remaining pool stake acquisition] [Jan Čapek — Mining software interview, 2020]
In an interview published in 2020, Čapek describes autotuning as adjusting individual chip frequencies and voltages at a given power setting. He considers it as a proprietary commercial layer above an open foundation. This historical interview does not establish the licence or terms of every current Braiins OS version. [Jan Čapek — Mining software interview, 2020]
The official Stratum V2 website names Jan Čapek, Pavel Moravec and Matt Corallo as joint designers. It attributes present maintenance to an independent open-source community. A Braiins founder's contribution must therefore not be confused with sole authorship or ownership of the standard by one company. [Stratum V2 — Designers and independent maintenance]
The Stratum V2 security specification describes authenticated encryption and server authentication. It requires a secure handshake for remote connections to upstream services, while allowing an exception on local networks. Protecting messages in transit does not itself establish correct accounting or a pool's future payout. [Stratum V2 — Protocol Security]
Job Declaration connects a miner's client to a participating pool's server. The client also operates with Template Distribution and the Mining Protocol. A Stratum V2 label on firmware alone therefore does not establish that a particular setup actually uses the miner's own block templates. [Stratum V2 — Job Declaration Protocol]
The specification defines DeclareMiningJob.Error and recommends switching to another pool with a JDS service or to solo mining after rejection. This option needs a working alternative configuration; the protocol itself guarantees neither uninterrupted mining nor the same reward arrangement after switching. [Stratum V2 — Job Declaration Protocol]
For the clearest picture, read this entry together with Braiins, Stratum V2, Mining Firmware.