S02 E04


Decentralization - a devtools discussion with Brooklyn Zelenka (Fission). Episode 4 (Season 2) of the Console Devtools Podcast.

Episode notes

In this episode we speak to Brooklyn Zelenka, CTO at Fission, a decentralized app framework for the future of web apps at the edge. We discuss the relevance of blockchain to web3 and decentralized web apps, why developers should avoid managing backend servers, the challenges of doing authentication and identity with local clients, and why web browser APIs are the place to build, not the native operating system.

Things mentioned:

About Brooklyn Zelenka

Brooklyn is the Co-Founder and CTO at Fission, where her team is building the next generation of web dev tools for the future of computing on the edge - levelling the playing field for teams of all sizes.

She founded the Vancouver functional programming meetup, and is the author of several Elixir libraries including Witchcraft & Exceptional. She was previously an Ethereum Core Developer, and continues to push the broader web3 space forward with standards like UCAN auth and the Webnative File System.


Brooklyn Zelenka: At Fission, we set ourselves a constraint right at the beginning that everything had to work directly in a browser with no extensions, no plugins, any of that stuff. That immediately ruled out blockchain. So we're saying, "Well, how can we apply a lot of these techniques to get the same sort of user and benefits of decentralization, interoperable data, permissionless, the option to exit, to self-host, and not to rely on a single provider in the web." That's taken us into all kinds of interesting areas.

David: What would you say is the advantage of using the web tech versus relying on some of the operating system APIs to do these things?

Brooklyn: So the browser is the most widely installed, cross platform, easy to use, easy to onboard piece of software that we've ever written. Everyone has one. It's on every device. Because of web standards, they work not identically, but pretty good, shockingly well. Learning native APIs is great, but you tend to be locked onto a particular platform, to the point that there have been attempts to apply web tech and web APIs to native app building.

David: Welcome to the Console Podcast. I'm David Mytton, co-founder of, a free weekly newsletter highlighting the best and most interesting tools for developers. In this episode, I speak with Brooklyn Zelenka, CTO at FISSION, a decentralized app framework for the future of web apps at the edge. We discuss the relevance of blockchain to web 3 and decentralized web apps, why developers should avoid managing backend servers, the challenges of doing authentication and identity with local clients, and why web browsers APIs are the place to build, not the native operating system. We're keeping this to 30 minutes, so let's get started. I'm here with Brooklyn Zelenka. Brooklyn, thanks for joining the Console Podcast.

Brooklyn: Hi, thanks for having me again.

David: Let's start with a brief background. Tell us a little bit about what you are currently doing and how you got here.

Brooklyn: I'm the CTO at a company called FISSION. We are a deep tech protocol engineering team working on the future of the web, offline, local first user agency, user owned data, and edge computing.

David: So when you hear about decentralization or web 3, the first thing most people probably think of is blockchain and maybe cryptocurrencies. Are those related, and what does decentralization mean in the context of web apps?

Brooklyn: Definitely related. I ended up in the space because of blockchains. I was hired actually by my now co-founder a few years ago to write a smart contract programming language that was both readable by lawyers and also formally verifiable, so actually came in through the programming language route more than anything else. The cryptocurrency portion of the space has really taken off and is the part that's getting the most attention, because people are making a lot of money. But it's certainly not the only thing happening. There's a lot happening in web, in browsers, in peer to peer communication. But the cryptocurrency space is, fundamentally, because there's so much money, funding a lot of the core R&D which is really nice for the web space.

Brooklyn: At FISSION, we set ourselves a constraint right at the beginning that everything had to work directly in a browser with no extensions, no plugins, any of that stuff. That immediately ruled out blockchain. So we're saying, "Well, how can we apply a lot of these techniques to get the same sort of user and benefits of decentralization, interoperable data, permissionless, the option to exit, to self host, and not to rely on a single provider in the web." That's taken us into all kinds of interesting areas. Why it's important? Well, for a lot of the reasons I just listed.

Brooklyn: Something recent, obviously Facebook had a very bad day a couple weeks back when their border gateway protocol went down, and with decentralization, you don't have to rely on a single provider to give you all of these things. So as an example, Twitter Blue sky is an attempt to decentralize Twitter. It's very early, but so that you wouldn't have to rely on one particular platform and you'd still be able to do all of your social media. We also don't think that hyper clouds, so AWS, GCP and Azure, should own all of infrastructure. Anyone should be able to participate. So that's also part of general movement.

David: One of the goals that you're aiming for at FISSION is to allow devs to avoid managing backend servers. Why do you think that's something that they shouldn't be doing?

Brooklyn: So for a lot of existing backend and full stack devs, it's something that they already not only are used to doing, but that they like to do. So there is this element of, "I enjoy my work. I want to work in whatever the language is, and that's only available on the backend." There's nothing wrong with that. But it is still a lot of work to build, maintain, deploy, secure a backend. We see data breaches on the regular, and having a disgruntled sysadmin with root access is maybe not the best way to set up an application, and it makes it really difficult for users to control their own data, so there's obviously the user agency side of this and also to comply with things like GDPR and all of these other data security regulations. If you aren't holding onto your user's data, if the user has their data instead, you can't possibly violate any of these rules because you're not holding any data.

Brooklyn: The other big reason is training. So somebody coming into the industry today has a towering stack to learn, stuff that 20 years ago, it wasn't quite as deep. You didn't have to learn Kubernetes. And if you can just focus on the front end, people coming out of a bootcamp, that's a reasonable amount of things to learn. So not having to learn front end, backend, DevOps, database design, all of this stuff means that we can keep pace with the number of developers that we actually need in the industry, because today we just literally can't train them fast enough.

David: So they can just focus on learning some of the front end technologies and some of the web tech that underlies all these apps. What is that? What APIs are developers having to interact with in the browser and what will they have to learn to get into this?

Brooklyn: Our goal with Web Native, which is the product, is so that someone could build a full stack web app that you would be able to build with a full stack tools, but only in the browser, and in a way that it only feels like you're working with React and you're making a couple calls out to a framework. Underneath that there's a lot going on. So the Web Crypto API is really important, specifically non exportable private keys. So you can generate a private key in the browser and have that not accessible to literally anyone, not even the user, so that key can't be stolen or removed from the context. IndexedDB is a storage in the browser, a little bit more like a database like abstraction versus something like just holding a memory or local storage.

Brooklyn: Putting a few more layers on top of that, definitely helpful, but IndexedDB, super useful. And then some other things like web workers and service workers as well, so that you can fake being online when you're offline or to intercept calls, because sometimes the browser expects there to be, or some tools to be an external call. And finally the post message APIs so that you can communicate across tabs and communicate that way, because if you're not always having to go out to a server, now you have to be able to communicate between tabs and between windows.

David: Okay, so before we get to the network advantages, what would you say is the advantage of using the web tech versus relying on some of the operating system APIs to do these things?

Brooklyn: So the browser is the most widely installed, cross platform, easy to use, easy to onboard piece of software that we've ever written. Everyone has one. It's on every device. Because of web standards they work not identically, but pretty good, shockingly well. Learning native APIs is great, but you tend to be locked onto a particular platform, to the point that there's been attempts to apply web tech and web APIs to native app building. So Windows has taken run at this. There's a couple versions on Linux. You can obviously wrap a browser window in something like Electron and ship that, so it's mainly a question of convenience and ease of deployment, ease of distribution. You literally type in a URL and boom you're there. You don't have to install anything. And it's just ubiquitous.

David: What would the equivalent of a data store be then, particularly as you need to you persist data, but then also syncing as well. How does that work?

Brooklyn: Having a distributed data store is widely needed and very exciting for the people that are looking at these problems, because obviously these are all on the bleeding edge. There's been a lot of work on this recently because we finally have just the base computer science and the raw APIs in the browser to actually do these things. There's obviously persisting data. It's one of the core components. You have identity and auth storage, and compute, really, that's fundamental building blocks. Storage, obviously we need a way of saying that, and especially in a browser context where you have limited storage, and at any time you might be disconnected.

Brooklyn: So distributed databases, there's a bunch of different approaches to this. When you go digging, a lot of distributed databases or decentralized databases in particular something more came to like an S3 bucket. So you're going to dump some data in there, give it a name, and you're done. Having the ability to run aggregates and queries and all the stuff that you expect out of a database is a harder problem, especially in a case where there's no primary database. So I have my phone and I have my laptop and maybe my phone is in airplane mode, but I still want to be able to make updates and use my app. And when I come online, that needs to sync up together and just work. But at the same time, my phone has a lot less storage than my laptop does, and maybe the storage quota allowance on each device is different.

Brooklyn: So we think about this kind of like a deck builder. If you have a card game where you say, "Well, I'm only interested in data that matches X, so only sync to me that portion of the data and I'll make updates to it and then distribute that out to everybody else that's interested in it." And this is also across users. Most databases are multi-tenant. And you and I might be interested in different data as well, and overlapping, but not necessarily the same. So we can copy some of the cards out of our deck and hand them over to you, but we don't need to hand you the entire stack, and we can then still make edits and changes to all of the bits of data, all the rows in this database and collaborate on the subset that we have in common.

David: That makes sense. Does that rule out some of the so-called big data type use cases? So I'm thinking where you might use something like Google's BigQuery, or perhaps one of the Amazon data warehouse products where you might have hundreds of terabytes of data and you want to run big jobs on them. Is that the kind of thing that just isn't possible with this tech or is it done in a different way?

Brooklyn: In principle there's nothing that prevents you from using this tech for those things. This, in a sense, just aggregates the database into separate components. So you have this very efficient sync and subscription model. When you have all that data co-located, you could have this in the petabytes. There's nothing preventing that at all. And there's actually some nice things about how, especially in our still early designs, but in our designs, the storage is very flexible, so you can arrange the data in any way, depending on how you need to process it. You could absolutely do it at scale. We're really focused down in the browser. The one thing to note is a lot of this, especially in decentralization and distributed tech in general, there's this trend going from, "Okay, well we used to have server and client, and there was the cloud and then there was your local device."

Brooklyn: And now we're seeing that there's a bunch of different kinds of compute in the middle. So you have your phone directly and it's very fast to do things directly, locally because you don't have to make a network connection, go out at all, and you do sort of 99% of what you need to do directly on device and keep it off of the wire. When you do need to go out to send some data to somebody else or send an email, any of that stuff, or synchronize data, now you have several layers. And you can kind of think about this in some ways as extending the cache metaphor that we have on the actual device. So you have the CPU and then various layers of cache, then RAM, then disk. And now we're saying, "Well, after disk, you have various layers on the internet." So your local device is really just a cache for the internet. So you can make a jump now to edge data centers, or even as we're seeing 5G and Starlink, they're putting a small amount of storage and compute right on the receiver.

Brooklyn: So to make that first jump from your phone out to the 5G network, there's storage and compute right there. That's hyper local, obviously. Past that you can jump out to a edge data center so something in your city or your region, still very, very local, something within some number of tens or at most hundreds of kilometers. And then finally out to proper cloud, US East One, the classic, where you do the really heavy data intensive stuff that's not as real time and not as time sensitive, but maybe needs to be processing huge amounts of data from multiple sources. So that's where we see this blending with the a Bigtable and Hadoop all of these things, because they need to do this analytical processing on many data sources. So that deck metaphor, you can build up a deck of these many sources that you've been collecting over months and then run compute over that.

David: It reminds me quite a bit of the storage tiers that you might get on Amazon S3. You get price reductions, and then you have different reliability and response time guarantees depending on whether you're using S3 Glacier or the Nearline storage or those kind of things. Moving this into the data store or even other APIs, how do you think that'll be exposed to engineers to develop on?

Brooklyn: I guess it really depends on the use case. If it's a cloud provider, they're probably going on a bucket this in a different way than somebody building things that are local first. Our Vision for the future is something called location transparency. So your storage and compute should be... Where that happens should be completely hidden from the end user. So if we are in this world where... And one thing I glossed over a little bit earlier is we've got this disaggregated database, we have these cards in this deck, and any one of those cards can be encrypted directly for the user. So now we're not being pushed through a central auth server all the time. So once you have something like that set up, it doesn't matter where you run your compute or do or storage. You can push this out to other resources transparently.

Brooklyn: So if my laptop is doing a bunch of other things in the background and I want to render a 3D scene, well, why should my entire computer slow down when I can push the assets out to an edge data center that's 50 kilometers away, so very, very nearby, and have it stream back the results to me. And if my whole UI feels completely responsive, and when it finishes, it'll send the end result back, to the user, nothing has changed. But if we're offline, well, I'm going to have to run that locally.

Brooklyn: So being able to give developers an API that just says, "Run this compute over this storage," is the goal, and there's some complexity there about how do you decide when to kick off a process remotely? Or even, "Okay, I know that there's a replica of this data elsewhere and I want that machine to run it because I know that they already have it right, as opposed to anyone." So there's some debate about how smart should the APIs be versus giving developers a nice DSL to say, "Under these conditions run this remotely." My ideal future picture is it just happens directly in the background and then expose lower APIs for people that need them, but we'll see how that all plays out.

David: So the developers will define something like a priority at the very basic level, but you could even go further to define different conditions depending on user characteristics or the type of data or the availability of the background processing. Is that how you think it would work?

Brooklyn: Yeah, exactly. So we can look at some compute and say, "Okay, this is going to be running over some large data sets, so we're going to need to push this out somewhere else, but only if I have network bandwidth available and latency to somebody that wants to pick up this job under these conditions and my local machine is below a certain threshold." So defining... That's a very granular way of looking at it, but defining maybe complexity levels, that kind of thing, to say, "Okay, if this goes beyond X, then kickoff a remote process." Or, depending on the use case, so maybe not with a 3D rendered scene that I was using before, but you can also race them and say, "I'll start running this locally and then kick off a process remotely and see whoever finishes first."

David: What would the security implications be for this kind of approach, and particularly if you are relying on local identity? That sounds like it's quite a big challenge.

Brooklyn: Doing fully distributed identity and distributed auth are the base building block for things. So people usually think, "Okay, well we've got data at the bottom and then we've got compute above that. And then we'll start adding on top of that everything you'd see in a web framework controller." But when we take a step back and look at it from a practical point of view... I mean, that's absolutely what's happening in the technology, but from a practical point of view, step one for doing anything practical is identity and auth. So there's a bunch of standards that have been coming out over the past couple years, we're also involved with this at the Decentralized Identity Foundation, to do decentralized identity where it's a uniform way of describing an identity that's based on public key cryptography, so using the same kind of keys that you'd sign your Git commits with, that can be either issued to you or generated by the user.

Brooklyn: So in our use case, we have the user generate them, so the user now has an identity and that user will then register with different services, or rather their identity will register with different services. And then auth as well. So auth needs to be baked directly in these models. So for read access, doing direct encryption, symmetric encryption on the data, and for any sort of mutation issuing credentials that say, "Hi, I'm allowed to do these things. Here's my proof that I'm allowed to do them." You're absolutely right that there's this challenge of, "Okay, well I want somebody to run a query over my data and my data is hidden." So today, in 2021, you have to have a trusted provider of some kind. There are ways of doing secure multiparty compute for certain classes of thing. There's versions of this for vote counting where you can prove that your vote was counted, but nobody can prove that you voted a particular way, as an example.

Brooklyn: But in the general case, yeah, you'll have to hand your data over, somebody will have to decrypt it, run compute over that, and send you the result back. And there's a couple ways of handling the security there, like breaking up the data set into different partitions so that nobody has the full thing. That's really dependent on the kind of query you're doing. The really exciting thing, and this is further out, so this is even deeper in research land, is something called fully homomorphic encryption, which is... It turns out that you can run computation over encrypted data without knowing the data, ever seeing it and getting results back. And you can even encrypt the function that's running over it, so you don't even know what you're running, and when the user gets it back, they can decrypt it, and the answer's correct.

Brooklyn: The reason that this isn't widely practical today is it's not very efficient. So they're working on improving the efficiency of that. And this is well funded research teams at big companies, because as you can imagine, your health data would be very useful to train machine learning models with, but you might not want to give some large company direct access to all your health records. So that's where that's going. In the meantime, yep, you'll have to use a trusted provider or be querying on public data. Or run it locally. You can also do, "Here's the public data, run the sub query. I'm going to run the private stuff locally and then combine those results."

David: Are you building a lot of this functionality as part of open source projects, because I suppose you are benefiting from the standardization of the APIs in the browsers, and that's why you are participating in the standardization projects. How are you thinking about the open sourcing of all these tools and technologies?

Brooklyn: So everything we do, I don't think that we have a single line of code that's not open source right now. We're big, big fans of open source. As you said, we've benefited tremendously from open source. It's not only the warm fuzzy feelings of giving back to the community, all of that. I mean, that's great, but it's also in our best interest to have everything open, have people be able hack on it, look at the code. When they report bugs, they can say, "Hey, I think it's on this exact line." All of that stuff. But also because we're so far out on the edge, the number of people that have the background and interest to get involved is not as high as in a lot of other projects. So having somebody be able to wander in and say, "Hey, have you thought about doing it like this or like that," is very useful, and standards are almost like a layer below open source.

Brooklyn: With a spec, you can then go and do multiple implementations in multiple different languages and different takes on it. Having the ability to say, "Oh, okay you have a project in Go and it's completely on the server." Yeah, the spec will work for you. Here's some of the things that you might want to build around that, but here you go. We've had a lot of success with that. UCAN, use controlled authorization networks is our form of distributed auth, and that's been getting picked up by a number of teams outside of the browser, as well as inside of it ,because it solves problems for them coordinating between services, a use case that we didn't even think about at all. So rather than having everyone reinvent the wheel, it's really great to put things out there and have people be able to think about it, adapt it, and especially use it in new ways.

David: So where should someone start if they wanted to either develop a brand new app or maybe start out thinking to shift their existing architecture from central servers or cloud over to being more decentralized?

Brooklyn: With the existing application, that's obviously the harder one, because you often have a lot infrastructure built up around the centralization, and it's a unspoken assumption in a system. The easiest, quickest, highest, and best use is starting with identity. So giving users the ability to own their identity means that you can then build distributed auth on top of that, which makes it able to then do... Eventually you can do encryption at rest on your server, which makes you much, much, much more secure, compliant with regulations, all of these nice things. If you have a totally green field project, that's a different story. That's great. So we have our, still in beta, but toolkit called Web Native. You can find that at That gives you everything that you need in a box, basically. Identity, auth, storage, compute, the whole thing. Offline first, et cetera.

Brooklyn: Other than that, A lot of these components are very easy to pick up on their own. The deeper into this that you go, the more changes you need to do relative to what you're used to, and making that feel familiar is the challenge for us, or companies like us, FISSION. Starting with DIDs, which can be both again directly on device, or you can issue them for your users. Verifiable credentials, which is related to the auth system that we have, gives you provable way, as granular as you like, to say this user is allowed to do this thing, or governments are using this to even... The provincial government here in Vancouver, so in BC, is using these to, or has at least experiments to say, "Okay, well this person is allowed to drive, but we're not going to tell you their age... Any other information about them, their address, any of that." So now you can walk around and say, "Hey, the government has signed off that I'm allowed to do this thing."

Brooklyn: It also makes it much easier... I mentioned this term earlier and didn't explain it, permissionless. In web 2.0, we went from having completely siloed systems to suddenly, with RESTful APIs, being able to issue tokens and say, "Hey, you're allowed to access these APIs with this token." Permissionless says, "Why even bother with the token? You can generate your own, or there is no token, please interoperate with us directly." This vision that we'd been sold for the past 15 years, that never completely materialized. We have a little bit of web hooks, things like that.

Brooklyn: It suddenly becomes much, much easier when you hand the user the keys to the identity, and now they can wander around to all these different services and say, "Hey, I have storage from over there, I have a bit of compute from over here, and I'm allowed to post over there. I'm going to grant you, the server, some abilities to do things across all of those to help me achieve some goal." So that's very exciting for a lot of developers because now they don't have to set up all this provisioning and an auth server and all this other stuff. You can literally just look at the public key signatures and you're off to the races.

David: And that brings the benefit of the user owning their data and being competent in the security of it, because they understand, or maybe they don't understand. That's the benefit. They can just assume that that it's been implemented and the technology is providing these guarantees.

Brooklyn: Exactly. You don't have to trust a particular provider anymore. Anyone can hook into this because they're standards, and because it's open. It's very easy to verify, "Okay, yeah, somebody else did this thing and here's the chain of signatures. Great." That's a guarantee.

David: And the tech stack that you're working on I understand is a mixture of Elixir and Elm. How have you found working with those technologies? And is there anything else that you're using that you find really useful?

Brooklyn: The actual framework, because it has to work with anybody else's tech stack, is actually written in TypeScript. A lot of our first party apps are in Elm, which is a delight to work with. When you get down to it, it's a DSL for writing web apps, so it does that extremely, extremely well with really good feedback and really good ergonomics. It's been surprisingly easy to hire for because I literally went on Twitter and said, "Who wants an Elm job," and we had more CVs than we knew what to do with. So yeah, Elm for a lot of our first party apps. We have Haskell on the backend, filling in the couple things that we actually need to manage still. So we do distribution of some information over DNS text records. So we need to have a DNS Route 53 manager. So that's in Haskell.

Brooklyn: We have a little bit of Go running because a part of our tech stack, IPFS, we use Go IPFS there. We use js-ipfs in the browser, and that is a distributed content store, I guess, aim to be a replacement for HTTP, where you're not looking for the address something lives at, you're asking for what's not where. So I want this piece of data and anyone can send it to you. We have been doing early experiments with WebAssembly, especially to speed up parts of the cryptography and anything that we need to do that's custom, especially with anything that's not in the Web Crypto API. Doing things directly in JavaScript is great, but we were finding really incredible speed ups by using Rust compiled down to WebAssembly, to the order of like 130 X speed up, which was pretty fantastic, taking things from being a second or two down to imperceptible. It always feels good.

David: Yeah, it makes a big difference for the user experience. Okay, great. Well, before we wrap up, I have two lightning questions for you. The first is, are there any interesting dev tools that you're playing around with at the moment?

Brooklyn: Nothing that spectacular since the last time I was on here. Myself and the team are still really enjoying Nix. So we have Nix across all of our projects, our production services are running NixOS. it's fantastic. The consistency's amazing. Highly recommend. And then esbuild, I think, has been taking the world by storm recently. So enjoying having fewer bundler headaches, because that's a whole thing.

David: And then what is your current tech setup? What hardware and software are you using.

Brooklyn: So I have really two setups. I have a M1 Mac, MacBook Air, and on that I run obviously MacOS, EMACS, Doom EMACS. I have a VIM clutch, which is foot pedal, because I'm using VIM bindings. So I press the pedal down, it's in insert mode, I lift the pedal up and it stops typing. And then I also use an iPad pro I dial in to a Digital Ocean server over Tailscale using Mosh, use a mechanical keyboard, so I now have two. I have an Anne Pro 2. I'm not actually sure how to say the name of the brand AZIO, just arrived, which was a Kickstarter mechanical keyboard.

David: And where can people find you online?

Brooklyn: So you can find me anywhere as Expede. That's my username, E-X-P-E-D-E. So Twitter, GitHub. We have a Discord and a Discourse for FISSION, so if you go to, there's links to all of that. And yeah, definitely drop into the Discord. We've had a bunch of people join recently because I was just giving a talk at ElixirConf, and it's a really nice supportive community, lots of links, maybe too many links, lots to discuss and learn over there.

David: Excellent. Well that's all we've got time for today. Thanks for joining us, Brooklyn.

Brooklyn: Great, thank you.

David: Thanks for listening to the Console Dev Tools Podcast. Please let us know what you think on Twitter. I'm @DavidMytton, and you can follow @consoledotdev. Don't forget to subscribe and rate us in your podcast player. And if you are playing around with or building any interesting dev tools, please get in touch. Our email's in the show notes. See you next time.

David Mytton
About the author

David Mytton is Co-founder & CEO of Console. In 2009, he founded and was CEO of Server Density, a SaaS cloud monitoring startup acquired in 2018 by edge compute and cyber security company, StackPath. He is also researching sustainable computing in the Department of Engineering Science at the University of Oxford, and has been a developer for 15+ years.

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