A freelance designer in Lagos needs to receive payment from a client in Berlin. The traditional financial system turns this into an ordeal: an international wire transfer takes 3-5 days to settle, currency conversion fees stack up, and intermediary charges eat 5-7% of the payment. Days of time lost. Hundreds of dollars vanish to friction.
Traditional cash apps were supposed to fix this. Instead, they created regional monopolies. Venmo works in the US. Revolut covers Europe. Paytm serves India. None of them talk to each other. Cross-border payments remain expensive, slow, and fragmented.
Crypto offered a different vision: a global, permissionless payment network. But the reality fell short. Crypto payments became too complex for everyday people. Most apps optimized for speculation rather than utility. The promise of frictionless global payments remained just that, a promise.
eth.cash: A Blockchain-Native Global Payment App
AppChain started with a simple belief: "a blockchain is nothing without successful apps." So they built eth.cash, a global payment app where users send money using just an email address, Farcaster handle, or Telegram handle. From your bank to anyone in the world in under one minute. No wallet management. No seed phrases. No blockchain complexity.
The timing couldn't be better. Stablecoin adoption is accelerating globally, and TradFi is jumping in headfirst. Western Union is launching its own dollar-backed stablecoin. Coinbase and Citigroup partnered to help institutional clients use stablecoins for faster payments. Zelle is exploring stablecoin-powered international transfers. Citi projects stablecoins could reach $1.9 trillion by 2030 in its base case, up to $4 trillion in a bullish scenario.
The momentum follows the GENIUS Act signed in July, which established the first comprehensive federal framework for stablecoins in the United States. Circulating stablecoin market capitalization jumped from $206 billion at the start of the year to over $308 billion today. Visa reports over $670 billion in on-chain loans over the past five years. Stablecoins aren't a crypto experiment anymore, they're officially mainstream.
In emerging markets facing inflation, USDC and other dollar-denominated assets are becoming the currency of choice. AppChain is building the infrastructure to make stablecoin payments as simple as sending a text message, exactly when the world needs it most.
The numbers prove it works: Circle USDC Grant Program selection, over 1.4 million transactions processed, 354,000+ addresses onboarded, 226,000+ account abstraction wallets created, and over $10.5M USD in volume YTD.
Back to that Lagos-Berlin payment. With ethcash, the client logs in using their email, connects Apple Pay, and sends USDC to the designer's email address. The designer receives it within minutes and will soon be able to hold the USDC in yield-bearing form while idle, spend it directly through ethcash, or off-ramp to local currency when needed. The entire flow takes less than 60 seconds of active time, with no wire transfer delays, no currency conversion spread, and no intermediaries taking cuts along the way.
The product keeps evolving beyond simple transfers. A bill splitter app lets users upload receipts and send payment requests to their contacts, while Telegram integration enables payments to any Telegram handle. Request payment features mirror what users expect from traditional cash apps, bringing familiar functionality to a global, stablecoin-powered infrastructure.
This is AppChain's values-driven approach in action: real utility over speculation, building infrastructure to "multiply the people who think about crypto like us." Their mission is clear: "AppChain exists to fill blockspace with transactions from apps that provide value to real people solving real problems."
The Case for a Dedicated Payments Rollup
To build a global payment app that feels as simple as Venmo, the AppChain team couldn't just build the dApp itself, they had to design the underlying infrastructure from the ground up. A general-purpose L2 would mean compromising on cost, UX, and control. So they built everything in-house, including their own bridge infrastructure.
Sub-Cent Transaction Economics
A $50 remittance payment with a $2 gas fee is unacceptable for mainstream adoption. When someone in Nigeria sends money to family or receives freelance payment, transaction costs must be measured in fractions of a cent, not dollars. Shared networks mean competing for blockspace, where costs spike during congestion and fees become unpredictable, ultimately pricing out users in developing markets who need these services most.
AppChain built a dedicated rollup on Arbitrum Nitro (Orbit stack) and gained full control over its fee market, achieving an average cost per transaction of just $0.0000017 (0.001 ETH across 570 transactions over 24 hours). That's the economic foundation that makes micro-payments viable and ensures users in developing markets can actually afford to use the platform.
Protocol-Level Customization for Web2-Simple UX
Mainstream users will not tolerate seed phrases, and they won't understand gas fees. ethcash required social and email logins from day one, which meant building Account Abstraction natively at the chain level rather than bolting it on as an afterthought. The result: over 226,000 AA wallets created where the blockchain becomes completely invisible to users. They interact via email and social handles without ever managing private keys. The chain has processed over 1.44M transactions, proving this approach works at true payment scale where crypto complexity disappears entirely.
Deep protocol control enabled seamless integration with thirdweb's Universal Bridge as core infrastructure. Users can onboard from over 150 countries with automatic provider selection that routes each user to the best option for their region, whether that's Stripe, Coinbase, Kado, or Transak. Apple Pay works, Google Pay works, and cards and bank transfers work. Users interact with payment methods they already trust, while flexible offramps to local currencies complete the full cycle.
This infrastructure matters most for users in regions with currency hyperinflation like Argentina, Turkey, and Nigeria, where holding USD stablecoins provides protection against local currency devaluation. Direct sequencer control for AppChain delivers the fast confirmations users expect from payment apps, ensuring the experience feels instant and reliable.
Brand and Ecosystem Sovereignty
AppChain is building a values-driven ecosystem where apps solve real problems for real people—supporting DePIN protocols, real gaming, and applications that reward meaningful contribution. ethcash isn't "a dapp on some chain." It's AppChain's flagship application, and they grow together with a unified brand and mission. Full control over economics, governance, and which applications to support allows AppChain to maintain those principles rather than competing for attention with thousands of unrelated applications on shared infrastructure.
"Caldera gave us the infrastructure to build what users actually need: simple, fast, global payments without compromise. Their Rollup Engine handled all of the complexity of launching on Arbitrum Orbit — easier than just clicking a button. We were able to focus on building the best payment experience while Caldera ensures the infrastructure just works." — Alex Carrabre, AppChain Team
How Caldera Enabled the Vision
AppChain's goals required infrastructure supporting global payment scale while maintaining sovereignty and customization. Caldera provided the complete stack.
A Production-Ready Payments Rollup
Caldera's Rollup Engine delivered the high-performance chain AppChain needed with fully managed infrastructure, allowing the team to focus on building ethcash rather than managing DevOps or Nitro stack operations. The scale speaks for itself: 1.4 million transactions processed across 354,000+ addresses, over 716,000 blocks maintained, and a transaction success rate approaching 100% (1.449M total transactions vs 1.446M completed). The platform scaled from zero to over 1 million transactions while maintaining reliability, proving the Rollup Engine can handle production-ready payment applications at scale.
A Shared On-Ramp for the Internet of Chains
Every Caldera chain connects automatically to the Metalayer, solving the liquidity cold start problem that typically plagues new chains. Instant connectivity to highly liquid networks like Base, BNB Chain, and the broader Arbitrum ecosystem means users can move assets from established networks without friction, while intent-based bridging routes assets across chains intelligently and finds optimal paths without requiring users to understand the underlying complexity.
The connectivity works both ways. AppChain gains access to liquidity from established networks, while ethcash becomes critical onboarding infrastructure for the entire Caldera ecosystem. Other Caldera rollups benefit from ethcash's 150+ country fiat onramp coverage and Web2-friendly UX, creating a network effect where each new integration strengthens the whole.
Consider a concrete example: A user in Argentina facing peso devaluation wants to protect savings in USDC and access DeFi yield. They onboard through ethcash using a local payment method, receive USDC on AppChain, then bridge seamlessly via the Metalayer to deploy capital on a DeFi-focused Caldera rollup earning 8% APY. As the ecosystem matures, this same Metalayer pathway will allow them to access new primitives like native yield-bearing stablecoins launching across the network, all from their ethcash hub. When they need to make a payment, they bridge back to AppChain and send via email to any recipient globally. ethcash becomes a shared payment rail for the Internet of Chains, bringing non-crypto natives into the broader ecosystem at scale.
The Networked Money Future
Stablecoins can finally become what they were meant to be: networked money that moves as freely as information across the internet. JPMorgan, PayPal, and BNY Mellon are integrating stablecoins into their operations, and the payment layer must be ready to handle global scale. ethcash proves that crypto payments can match Web2 simplicity while delivering Web3's global reach and programmability.
AppChain demonstrates what happens when you build with values-first principles and focus on solving real problems for real people—you attract users building real businesses. The numbers tell the story: 1.4 million transactions, 354,000+ addresses, over 226,000 account abstraction wallets making blockchain invisible to end users. This is what mainstream adoption looks like when infrastructure meets intention.
For builders considering blockchain infrastructure for payments, the path is clear. Custom rollup with full sovereignty, integration into existing applications, sub-cent economics that make small payments viable, day-one liquidity access, complete stack covering rollup deployment through ecosystem connectivity, all in a single partnership. Caldera’s infrastructure is proven at scale across 50+ live rollups processing millions of transactions.
The future of payments isn't regional apps that aren’t interoperable. It's a unified network where value flows as freely as information, where sending money to Lagos is as simple as sending an email, where users never need to understand what blockchain is to benefit from it. AppChain is building that future on Caldera, and the infrastructure is ready for the next wave of payment applications to scale globally. Building the future of payments? Get in touch to learn more.
About Caldera
Caldera is powering the next internet. Its architecture consists of two core components: the Rollup Engine and the Metalayer. The Rollup Engine is a modular operating system used to launch high-performance, custom chains on leading chains and frameworks like Arbitrum, Optimism, Base, and ZKsync. The Metalayer then automatically connects every chain into one network. Through this interoperability protocol, all chains access shared liquidity and secure, intent-based bridging that transforms fragmented networks into a unified Internet of Chains. And now with the launch of the Caldera Bridge Preview, Metatoken, and Stablecoin Module, this expands the product suite and market size that Caldera is tackling.
