Start with the basic problem: why does crypto need a “stable” version at all?
If you’ve read our earlier explainer on blockchain, you know it’s a way of recording transactions across a network of computers without needing one central authority. Cryptocurrencies like Bitcoin run on blockchains — but they have one major flaw for everyday use: their price swings wildly. Bitcoin can rise or fall 10% in a single day. That’s exciting for an investor, but useless for someone trying to pay a salary, settle an invoice, or buy groceries — you can’t price a loaf of bread in something that might be worth 10% less by dinnertime.
A stablecoin solves this. It’s a cryptocurrency designed to hold a constant value, almost always pegged 1:1 to a real-world currency — usually the US dollar. One stablecoin token is built to always equal one dollar, no more, no less.
How does a coin actually “stay” worth one dollar?
This is the single most important mechanic to understand, and it’s simpler than it sounds. A fiat-backed stablecoin (the dominant type) works like this: for every token the issuing company creates and sells, it sets aside one real dollar’s worth of assets — usually cash or short-term US government debt called Treasury bills — in a reserve. This reserve is the company’s promise: if you ever want to convert your stablecoin back into real dollars, the company has the actual money sitting there to give you.
This is fundamentally different from Bitcoin, which has no backing asset at all — its value comes purely from supply, demand, and belief. It’s also different from a Central Bank Digital Currency (CBDC), which we covered in an earlier article: a CBDC is issued directly by a government’s central bank, while a stablecoin is issued by a private company (like Tether or Circle) and merely uses a government’s currency as its reference point.
The market, in numbers
This isn’t a niche experiment anymore. The total stablecoin market cap reached $251 billion, with Tether’s USDT and Circle’s USDC together accounting for more than 86% of that market share. By comparison, even a well-known fintech giant’s stablecoin, PayPal’s PYUSD, holds a vanishingly small 0.0036% share — showing just how concentrated this market is around two dominant players. New Kerala
What is a “payment rail,” and why does everyone keep using that phrase?
You’ll see this term constantly in stablecoin coverage, so let’s define it clearly: a payment rail is simply the underlying infrastructure that moves money from one party to another — the “tracks” the money travels on. Traditional payment rails include the banking wire system, card networks (Visa, Mastercard), and ACH transfers. Each of these involves multiple intermediary banks, takes time to settle, and charges fees at each step.
A blockchain-based stablecoin functions as a new, alternative payment rail. Because it moves on a blockchain rather than through a chain of banks, a transaction can settle — meaning the money is fully and irreversibly transferred — in seconds or minutes, anywhere in the world, instead of the one-to-three business days a traditional cross-border wire takes.
On-chain vs off-chain: a distinction worth knowing
When something happens “on-chain,” it means the transaction itself is recorded directly on the blockchain — visible, verifiable, and settled there. “Off-chain” means the activity happens through a traditional, private system that isn’t recorded on a public ledger. A lot of current stablecoin payment products are hybrids: the movement of value happens on-chain (fast, cheap), but the part the end customer actually sees — say, their bank app showing a deposit — happens off-chain, through a conversion step back into regular local currency.
Why companies care so much: the fee problem
Every time a customer pays with a credit or debit card, the merchant pays a small percentage to the card network and the issuing bank — known as an interchange fee, typically 1.5–3% of the transaction. For a company processing billions of dollars in sales, that adds up to a genuinely massive cost. Stablecoin-based payment rails bypass much of this traditional banking and card infrastructure, which is the central financial incentive driving large retailers and tech platforms toward this technology — not novelty, but cost savings at scale.
The rulebook: what is the GENIUS Act, in plain terms?
The GENIUS Act (Guiding and Establishing National Innovation for US Stablecoins) is the US federal law that creates official rules for stablecoin issuers — covering how much reserve backing they must hold, what those reserves can be invested in, and what anti-money-laundering checks issuers must perform. Before this law, stablecoins operated in a regulatory grey area; companies building products on top of them had real uncertainty about whether their plans were even legally safe to pursue. The Act’s passage is precisely why so many large companies accelerated their stablecoin plans through 2025 and into 2026 — regulatory clarity removed a major business risk.
Key terms, summarised
- Stablecoin: a cryptocurrency pegged to a stable asset, usually the US dollar
- Reserve: the real-world assets (cash, Treasury bills) an issuer holds to back each token
- Peg: the fixed exchange rate a stablecoin is designed to maintain (e.g., 1 token = $1)
- Payment rail: the infrastructure used to move money from payer to payee
- Settlement: the point at which a transaction is final and irreversible
- Interchange fee: the percentage card networks and banks charge merchants per transaction
- On-chain/off-chain: whether an activity is recorded on a public blockchain or through a private traditional system
Why this foundation matters
With these terms in hand, the next article — covering why Visa, Meta, Walmart, and several of the world’s largest payment networks are racing to build stablecoin infrastructure in 2026 — should read as a logical business story rather than a wall of unfamiliar jargon. Every company mentioned in that piece is essentially trying to either own a faster, cheaper payment rail, or avoid being left paying interchange fees to competitors who’ve built one.
Visit decode-finance.com for more insightful content.