S11 E1: Pavlenex & Kukks on BTCPay Server, Soft Simon on Mempool

BTCPay Server and Mempool.space are two of my favorite Bitcoin projects. They’re uncompromisingly open source, they have great teams of developers, they’re surrounded by some of the brightest community members, and they provide true utility to the Bitcoin ecosystem.

So in late February 2022, when I was given the chance to travel to Istanbul to attend Fulmo’s Lightning Network hackaton (LightningHackdayIST), I didn’t think twice and packed my mobile recording equipment. What I was able to capture, beyond the unforgettable memories of spending my 30th birthday with a contagiously enthusiastic group of Bitcoin builders, is three invaluable interviews with four of the best and most promising projects in the space. In this first episode of season 11, I’m presenting two of them: BTCPay Server (represented by Pavlenex and Kukks) and Mempool.space (represented by Soft Simon).

I first heard about BTCPay Server sometime in early 2018, when the journey of making BitPay an obsolete payments processor was still in its infancy. The client was too technical for most users, while the documentation was pretty much non-existent. Clearly, Nicolas Dorier’s ambition was still far from fulfilment. But it was people like Mr. Kukks and Pavlenex who helped make the project more accessible to anyone looking to accept BTC payments without middlemen, financial censorship, or KYC/AML requirements.

In February 2018, Kukks submitted his first contribution to the BTCPay Server project: he inquired about adding support for Ethereum. In the months that followed, he started coding almost exclusively for the project and his GitHub activity grid got filled with green blocks more consistently. BTCPay gave him a new sense of purpose and he was able to grow as a coder while also helping the payments processor reach new heights with various integrations. Needless to say, ETH never got added due to the complexity involved in operating nodes and Kukks stopped trying to push any altcoin.

This interview might highlight his budgeting skills and commitment to open source, but the 4000+ commits he submitted to the BTCPay Server GitHub are invaluable for the entire community and for the freedom of transactions at large.

On the 1st of March 2018, Pavlenex also made his BTCPay GitHub debut with a proposal to integrate U2F authentication via Trezor and Ledger hardware wallets. He created his GitHub account specifically to post this request – and in the coming months, as he kept on using the free open source payment processor, he kept on coming back to suggest other features and refinements. By September 2018, Pavlenex became an active contributor in the documentation section – where he explained to newcomers how to use BTCPay for their various use cases.

By December 2018, Pavlenex turned into a bona fide BTCPay team member: his first YouTube tutorial got published on the 11th, while the docs.btcpayserver.org page went live on Christmas Eve. In the coming months, everyone trying to set up BTCPay would sooner or later get in contact with Pavlenex to receive support.

With Mempool.space, Soft Simon also did the seemingly-unthinkable: he made Bitcoin transaction fees easier to understand and predict. For years, bitcoiners have used transaction information from their own nodes or graphical representations such as Jochen Hoenicke’s. But Simon thought that visualizing the activity on the Bitcoin blockchain can be done in a more elegant and aesthetically-pleasing way. So on July 21st 2019, the Swedish developer created a GitHub repository called “mempool” and spent the rest of the year making small additions to it.

But it wasn’t until February 2020 that Mempool.space became Soft Simon’s main focus. In the beginning, he coded the foundational elements. Within 22 days, he would be joined by Bisq contributor Wiz. And in a few months, their combined efforts would put together what soon enough turned into the most popular way to estimate BTC fees, verify the status of pending transactions, and observe mining-related statistics.

Since Mempool is a free open source project, it soon got integrated in pretty much every Bitcoin full node dashboard (RaspiBlitz, Umbrel, MyNode, Run Citadel) and significant wallet (examples include Electrum, Blue Wallet, Specter, and Mercury). Even in the absence of the graphic user interface, it serves as a useful fee estimator that other projects can use. Also, big players took notice and provided Simon and Wiz with all the funding required to maximize the potential of Mempool.space.

Given the significance of BTCPay Server and Mempool, there is no proper way in which I can express into words how much this particular interview means to me. The recording doesn’t merely mark the premiere of a new season of the Bitcoin Takeover Podcast – it’s something that helped me rediscover my love for podcasting and reminded me why I still record interviews. The true heroes in Bitcoin aren’t the investors and fund managers who get on television to talk about their grand plans to pump everyone’s bags. They’re not the ones who bring you hundreds of thousands of social media engagements and YouTube views either. Everything starts with the brilliant open source contributors who make Bitcoin more accessible to everybody.

I hope that this interview captures some of this newfound passion of mine – as it’s also the first one that I record in the same room with the guests while recording video, so I was more nervous than usual. Last but not least, I would once again like to thank Jeff from Fulmo for having me at the event. Both my presentation at Lightning Hackday Istanbul and the three interviews that I recorded at the venue happened thanks to his grace and generosity.

Listen to Pavlenex, Kukks, and Soft Simon on Spotify, Apple Podcasts, YouTube & more!

The episode is available across all major streaming platforms. But if you’re looking for a registration-free alternative which doesn’t track you, is privacy-friendly (you can open it in the Tor browser) and allows you to download the audio file for offline listening, then I recommend you to use this native player.

Furthermore, if you’re into the value for value podcasting movement, then you can also find the Bitcoin Takeover Podcast on Sphinx, PodcastIndex, Breez, and every other place.

This episode is Sponsored by Vaultoro and Wasabi Wallet

Joshua from Vaultoro is a big fan of the show and I’m happy that he sees potential in my work and supports it without caring about numbers and growth statistics. So I must thank him for his generosity and invite you to check out Vaultoro – the exchange where you can trade with honest money (bitcoin, gold, and silver). 

None of this is financial advice from me, but I’m pretty sure that the shiny rock is a better store of value than any fiat currency or “stablecoin”, so maybe it would be wise to use this commodity to preserve your purchasing power during bear markets and get back into bitcoin as soon as you’re convinced that the downwards movement are over. You can also have the gold bars delivered to your house… because you know, if it’s not in your safe then it’s stored somewhere in Switzerland where you can’t touch it whenever you please. For more information, check out Vaultoro’s website.

Also, Joshua from Vaultoro is sponsoring a Lightning Network faucet – he hopes that Bitcoin’s second layer will one day become potent and popular enough to replace the smart contract and tokenization features of Ethereum. And he also supported Giacomo Zucco’s layer 3 RGB Spectrum experimentation from 2019.

If you would like to increase your network-level and transaction privacy, you should download Wasabi Wallet on your computer. It routes your connection through the Tor network to hide your IP, it downloads block filters so you validate your own transactions locally without appealing to a trusted third party, and it also connects to your own full node to boost your financial sovereignty. Extra features include advanced hardware wallet integrations, easy UTXO management, address reuse prevention, and even a lurker wife mode.

Wasabi is best known for its link-breaking CoinJoins, which are giving a hard time even to the EuroPol. Use the wallet to increase your financial sovereignty, but don’t do any illegal stuff – use your financial sovereignty with responsibility (also read the Wasabi terms of service).