Tomorrow We Launch Cosine Wallet
December 8th, 2025. That’s tomorrow. After months of building, debugging, and honestly just grinding through problems we didn’t even know existed when we started, we’re finally launching Cosine Wallet.
Joseph, Eben, and I worked on this for months. Joseph literally traveled from his city to Lagos every week to work on the mobile side of things. Every. Single. Week. Eben focused on the product and brand design, making it didn’t just work but actually felt good to use. And me? Backend, blockchains, and whatever else needed doing to make it all work together.
Why We Built This
Here’s the thing that frustrated us enough to build Cosine: there’s no self-custody wallet that lets you actually spend your crypto without converting back to fiat. Everyone talks about crypto adoption, but then what? You hold your USDC and USDT, and when you want to use it for anything real, you’re back to off-ramping. That’s broken.
We wanted to fix that. So we built a wallet where you can spend your stablecoins directly: fund cards, buy giftcards, pay bills - all without gas fees. Though I’ll be honest, some of those spending features are coming after the release of the first version, but the foundation is there. You can send, receive, buy and sell crypto in over 170+ countries. Swap tokens without gas fees. Create child wallets. Access thousands of dapps. It’s everything a wallet should be, but with the ability to actually use your crypto in the real world.
The Journey Was Messier Than We Expected
When we started, there wasn’t even a clear roadmap for crypto development on our stack. MetaMask was slow back then, and we knew nobody would use a wallet that lagged, meaning we couldn’t build on top of their open source infrastructure. So we got our hands dirty. Really dirty.
Mnemonic generation was way too slow at first. We had to rewrite it in native code just to make it is fast enough. Storage? We tried async storage and it was terrible, and we began to look for a way to optimize it and we found MMKV. And those were just two of the issues. Every layer of the product required us to go lower level than we originally planned.
We built across 7 EVM blockchains - Ethereum, Base, Optimism, Arbitrum, Polygon, BNB Chain, Avalanche. And honestly, we created some tools in-house that we’re pretty proud of. We’ll probably open source them later because other builders shouldn’t have to solve the same problems from scratch.
What Happens Tomorrow
You can download Cosine Wallet starting tomorrow.
If you’re someone who believes crypto should be usable, not just holdable - this is for you. If you’re tired of gas fees stopping you from swapping between tokens, this is for you. If you want self-custody but don’t want to feel like you need a computer science degree to use your own money, definitely for you.
We’ll Be Hiring Soon
Next year we’re going to start bringing on cracked engineers and growth people. If you’re the type who sees a hard problem and gets excited instead of scared, keep an eye on our careers page.
Our vision is simple: build a future where anyone, anywhere can use crypto as easily as cash. That means onboarding the next billion web2 users onchain by abstracting away all the technical jargon that keeps normal people out. If that mission sounds interesting, we should talk.
This article was supposed to be about the engineering behind the product. But for now, this is the little part of the story. Tomorrow, Cosine Wallet goes live, and honestly, we’re just really proud of what we built.