The case for offline mobile signers for crypto transactions

Navigating the crypto ecosystem is quite a ride and is riddled with numerous challenges and roadblocks, starting with how to acquire cryptocurrency and spanning to how to use it securely without losing it.

There is currently a plethora of blockchains, and with each one comes a different standard of dealing with the challenges above. Naturally we end up in a situation where there are multiple wallets, with different interfaces and different ways to integrate them.

Despite this fragmentation, wallets end up being the means by which most people interact with blockchains, more specifically, the blockchains that the specific wallet they chose supports. To support more blockchains, you'll have to install multiple wallets, increasing the amount of things you need to be mindful of to avoid problems, thus increasing friction.

The problems with current wallets

Wallets come in numerous shapes and forms but usually either a mobile app or a browser extension (or both), each with multiple tradeoffs:

• Extensions bring with them massive security risks, both for your crypto keys and for your regular browsing history (extensions have read access to everything you browse)
• Mobile apps come with the problem that they usually don't work on mobile websites, which completely beats their purpose. (unless there is some trick in place, like running a browser within the app, or routing communication between the app and the mobile window through a backend, etc).

Wallets are what I like to call: "asset first". They will show you the current balance of your aggregated assets that are in your different crypto accounts. Their focus is usually on simulating a "you are your own bank" feeling. This makes it difficult to create one wallet to rule them all because different blockchains, protocols, and dApps (decentralized applications) have varying standards, transaction types, and custom behaviors. Wallets often need to integrate deeply with blockchain-specific quirks, making them siloed and specialized for certain ecosystems. As a result, cross-chain compatibility becomes a complex problem, that forces users to juggle multiple wallets or interfaces, which dilutes the seamless "bank-like" experience they aim to provide.

Additionally, the wallet approach and how it the wallet is implemented, also gives the specific blockchain more leverage in capturing a user-base that ends up locked into that specific crypto ecosystem: if the wallet doesn't implement a way to execute a specific action like bridging assets to a different chain, most users just won't do it, and the likelihood of a competing wallet capturing the initial user base is very unlikely thanks to laziness.

To be completely fair though, wallets end up like this because the whole point to have a wallet is to simplify some things, at the price of other things: it's all about the user experience.

This article is about how I prefer offline mobile signers for crypto transactions instead of wallets.

Mobile signers as a better paradigm

The difference between a wallet and what I call "mobile signer" in this post are the following:

• A mobile signer approach is "action first", it is build around making deliberate and secure interactions vs the "asset first" approach of wallets, more focused on storing and sending value. This difference deeply influences how they function and what they prioritize.
• Mobile signers are just tools to manage cryptographic keys and provide secure ways for how to use them for authorization and authentication. They do not depend on external APIs or services to exist or to function: they could even work completely offline.
• Mobile wallets are clear signing first. Clear signing means that the mobile signer tells you exactly what it is you are currently going to do, would you use a key to sign a transaction.

A mobile signer is simply a tool to interact securely with blockchains, better aligned with the practical needs of users. Wallets don’t actually store coins or assets, they are abstractions built around cryptographic keys. However, their "asset-first" design focus creates a fundamentally different user experience compared to mobile signers, whose goal is to act as a clear and secure gateway for blockchain interactions.

In a nutshell, wallets frame everything around "managing value", whereas mobile signers re-imagine the experience to prioritize action, clarity and security.

Security without compromising UX

Naturally the first point that can be raised is that a mobile signer is only for experts and not for the majority of people, but I believe that a good mobile signer is only as good as how simple it is to use it securely, meaning, using a mobile signers makes doing the wrong thing very difficult.

Features of a signer that I'd love to use:

• Mobile-only (no Ledger or hardware device)
• Simple login capabilities for dApps
• Companion dApp for viewing balances and portfolio (keeping heavy logic outside the signer)
• QR code-based transaction flow:
  • Scan transaction QR from dApp
  • See clear action description on mobile
  • Sign and return via QR code
• Optional NFC support for devices that prefer it

The closest implementation I know of right now is the Polkadot Vault, which nails a lot of these concepts. But there's more to consider here.

The benefits of mobile signers

The beauty of mobile signers is that they're fundamentally simpler than traditional wallets. They don't try to be your crypto bank, they just handle the critical security bits really well. This separation means you can have rock solid security (your keys never touch the internet) while still getting a great user experience through companion apps or websites that handle all the fancy UI stuff.

Think about it: when you're signing a transaction, do you really need to see your entire portfolio? Or do you just need to clearly understand what you're about to do? Mobile signers cut through the noise and show you exactly what matters: "You're about to send 0.1 ETH to this address" or "You're approving this contract to spend your tokens". No gibberish, no confusion.

This approach also solves the multi-chain mess we're in. Since a mobile signer focuses on cryptographic operations rather than chain-specific features, one tool can work across any blockchain. No more juggling five different wallet apps.

But there are some hurdles to overcome. We need better standards for how dApps communicate transaction intents to signers. The QR code flow works, but it could be smoother. And we need more dApps to support this approach because right now it's still easier to just tell users "install MetaMask" than to implement a proper signing flow. Polkadot is an crypto ecosystem where I believe this to be completely solved: you get clear-signing technically for free thanks to the metadata.

Looking ahead, I see mobile signers becoming the default way people interact with blockchains. Not because they're more secure (though they are), but because they're actually simpler. They do one thing - signing - and they do it well. Everything else can live in whatever interface makes the most sense for that specific use case.

For this to happen, we need:

• Better standards for representing transaction intents
• More dApps supporting QR-based signing flows
• Improved backup and recovery solutions that don't compromise security

The tools are already here, but we just need to start building with this paradigm in mind. If you're a developer, consider how you might support mobile signing in your dApp. If you're a user, try out tools like Polkadot Vault and push for better signing support in the apps you use. The sooner we move away from the "wallet as everything" model, the better off we'll be.

And I might just build this thing myself, although I'm happy to support any initiative that aims to do so.