The stablecoin sandwich: Making on/off-ramps faster

Stablecoins offer unmatched speed and affordability, but one critical question remains: how do users move in and out of stablecoins in real-world transactions? That’s where the “stablecoin sandwich” comes in.

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By combining local on- and off-ramps with blockchain-based stablecoin transfers in between, the sandwich model creates a frictionless user experience that retains crypto’s benefits while remaining grounded in local realities.

The stablecoin sandwich isn’t just a workaround - it’s becoming the infrastructure of modern remittances. In 2024 alone, global stablecoin transaction volume surpassed $10 trillion (Circle/Chainalysis). 

At the same time, over 30% of remittances to Sub-Saharan Africa were routed through crypto rails, up from 9% in 2021 (Triple A, 2025). And Kenya, Nigeria, and Ghana saw triple-digit growth in stablecoin-enabled financial services (CV VC Africa Blockchain Report, 2025).

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How the stablecoin sandwich works

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1. Local on-ramp: The sender uses fiat currency to purchase a stablecoin via a trusted on-ramp partner. This could be a local payment processor, mobile money agent or OTC provider offering stablecoin access
2. Stablecoin transfer: The stablecoin (e.g. USDT or USDC) is then transferred cross-border - instantly, securely and cost-effectively - bypassing SWIFT and traditional banking rails
3. Local off-ramp: The recipient cashes out into local currency through an off-ramp, like a mobile wallet, agent network or crypto-to-fiat exchange

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Why the stablecoin sandwich works

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• Speed and efficiency: Stablecoin transfers settle in seconds or minutes, rather than the 2-5 days often required by banks and SWIFT
• Cost saving: Traditional remittance services charge 6-10% in fees (World Bank, 2024). With stablecoins, that cost drops by over 60%, especially in high-volume corridors like Nigeria, Kenya and Ghana
• Flexibility and resilience: Stablecoins provide a dollar-equivalent store of value in markets plagued by inflation or currency instability
• Localised liquidity: By partnering with regional players, remittance providers ensure users can access funds in formats they trust and use daily - like mobile money or cash-out agents 

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In a continent like Africa, where over 70% of the population is unbanked or underbanked (Global Findex, 2023), this model is more than technical innovation - it’s a leap towards financial inclusion. 

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Fraud patterns in the sandwich ecosystem

While stablecoins enable faster, cheaper, and more inclusive cross-border payments, the risk of fraud hasn’t disappeared - it’s simply evolved.

In many ways, these risks mirror those faced by traditional financial systems: weak KYC controls, identity fraud, illicit fund flows, and infrastructure gaps. But because stablecoins operate on newer, decentralised rails, the vulnerabilities often show up in different places - especially at the seams where fiat meets crypto.

According to Chainalysis, over $23 billion in crypto was linked to illicit activities in 2024, with a significant share routed through on/off-ramp loopholes. In remittance-heavy markets with fragmented regulatory oversight and informal financial infrastructure, vulnerabilities are especially pronounced.  

Some emerging fraud vectors we’ve observed include: 

• Double-dipping wallets: multiple cash-outs using spoofed or duplicated identities
• Ghost agents: nonexistent offramp agents who disappear with funds 
• Split laundering: breaking large illicit transfers into multiple small “legit-looking” transactions 
• Cross-border identity morphing: exploiting differences in KYC rigour across jurisdictions

Importantly, stablecoins shouldn't be seen as inherently riskier — the real priority is developing fraud prevention strategies tailored to this new financial stack.

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Building a fraud resistant sandwich

To build a robust and fraud-resistant stablecoin sandwich, remittance providers must: 

1. Develop deep networks of trusted partners. Build on/off-ramp relationships with vetted mobile money providers, OTC desks, and agent networks who adhere to strong compliance standards.‍
2. Embed end-to-end risk monitoring. Fraud doesn’t just happen on the blockchain; providers must monitor on-ramp transaction behaviors, wallet usage patterns, off-ramp device and identity integrity, and corridor-specific red flags.‍
3. Localise fraud detection logic. Risk scoring should adapt by region and corridor. What’s “suspicious” in the United Kingdom might be normal in Kenya, making local insights incredibly important. 
4. ‍Simplify user experience, harden the backend. Users shouldn’t have to understand blockchain mechanics - they should see a smooth, familiar interface. But behind the scenes, businesses must run multi-layered security systems: real-time monitoring, geolocation checks, and behavioural AI.

Towards a safer, smarter stablecoin future

Stablecoins are solving real-world financial pain points - from remittance costs to liquidity droughts to banking access gaps, and the stablecoin sandwich model makes real-time, cross-border money movement possible. 

But every new on-ramp is a new attack surface. Every cash-out point is a potential vulnerability. If left unchecked, these weak links can undermine trust in the entire ecosystem.

Fraud prevention is not a bolt-on feature. It’s core infrastructure - especially in high-risk, high-velocity environments like remittances.

To thrive, providers must bake security into every layer of the sandwich. That means localised risk scoring, network-level intelligence, partner due diligence, and AI-powered fraud orchestration.

At Orca, we help remittance platforms build smarter, safer ecosystems - combining behavioural analytics, corridor-specific insights, and omnichannel risk monitoring into a single platform designed for stablecoin-powered growth.

Build with confidence. Get your free fraud assessment with Orca.