EVERYTHING IN FINTECH, FROM FIRST PRINCIPLES.

Follow the money.
All of it.

Interchange, instant rails, chargebacks, SWIFT — the machinery under every payment, drawn and animated instead of jargoned. Vendor-neutral. Global. Free.

▶ Take the tour: The Journey of $100 New here? Start at zero →

The tour is the thrill; “start at zero” is the foundation if it doesn't click. Prefer to browse? The full guide →

SCROLL ↓
RIGHT NOW, WHILE YOU READ THIS

The rails never sleep.

0
UPI payments since you opened this page · India · ~8,900/sec
0
Pix payments since you opened this page · Brazil · ~3,000/sec
0
Card payments since you opened this page · worldwide · ~20,000/sec
$0
Interchange collected since you opened this page · worldwide estimate
Directional estimates from published monthly volumes (NPCI, BCB, network reports). Good for feel, not for accounting.
THE CURRICULUM

Start at zero. Finish fluent.

Every chapter, in the order the guide teaches them — built to read top to bottom, though each one stands alone. New here? Begin at the top.

START HERE · First principles
The history of moneyCattle, cowrie shells, coins, paper, gold, fiat — how money got from barter to a number on your phone.12 MIN What money actually isThere is no money in your bank account — ledgers, reserves and settlement, from zero.17 MIN The banking systemA bank doesn't store your money, it lends it — fractional reserves, the central-bank pyramid, and why banks run.10 MIN Blockchain from zeroA ledger with no bank: keys, consensus, smart contracts, L2s — no hype, no scorn.14 MIN
The card machine
The card, explainedCredit or debit? Whose money, and when — plus APR, the grace period, and which to tap.8 MIN The journey of $100Five players, six seconds, three skims — the anatomy of every card payment, animated.8 MIN Who makes money when you tapGateway vs processor vs acquirer vs PayFac — the food chain and its business models.14 MIN One tap, four kinds of moneyDebit, credit, charge, prepaid — same tap, four money sources at four very different prices.13 MIN Every place a card says yesPOS, e-commerce, in-app, QR, phone-as-terminal — where a card is read decides the fraud and the fees.12 MIN The fee nobody votes onWho sets it, what moves it, and how three regulators on three continents went to war over it.12 MIN The store never sees your cardTokenization, 3DS, and the liability bargain behind every online checkout.6 MIN The card number that isn'tYour PAN leaked last night. It didn't matter — DPANs, cryptograms and vaults, animated.8 MIN
When things go wrong
When the $100 comes backThe undo button: disputes, representment, and why a lost dispute costs 2.35× the sale.11 MIN The $33B fraud economyCard testing, account takeover, triangulation, APP scams — crime's supply chain, animated.12 MIN
Beyond cards
What Apple Pay actually doesDevice tokens, secure elements, and why your phone is safer than your card.7 MIN The instant payment revolutionUPI, Pix, FedNow, SEPA Instant — how the world rebuilt payments, and who's winning.13 MIN Pay from your bank, no cardPay-by-bank, aggregation and VRP — near-free, instant, chargeback-free, and the threat to interchange.10 MIN Four easy payments, one hard businessWho really pays for "interest-free" — and the regulators closing in worldwide.6 MIN
Global money
The $65 haircutSWIFT, nostro accounts, and why money never actually crosses a border.12 MIN The exchange rate IS the feeThe DCC trap, the rate shade, and why "zero-fee" transfers aren't.5 MIN
The builder side
How anyone launches a cardBIN sponsors, program managers, issuer-processors and just-in-time funding — the stack behind every fintech card.12 MIN The other half of the swipeAcquiring, underwriting, MoR vs PayFac vs ISO, reserves and the merchant discount.12 MIN
Digital assets
Money without middlemenA push wire, not a card: on-chain settlement, the ramp problem, and where crypto met Visa.8 MIN A dollar that settles like a textThe float business model, the GENIUS Act, and why the ramps — not the rail — are the battle.13 MIN
How we got here
Payments wasn't designed. It happened.The forgotten wallet, the Fresno Drop, Wirecard, demonetization — twelve accidents, one timeline.5 MIN
Use it · Tools, reference & play
Fee calculator Decline decoder MCC lookup Card anatomy BIN explainer Fee benchmark Rails atlas Primary sources Run a PayFac · game Settle quiz · game
THIS WEEK IN PAYMENTS

What the headline leaves out.

The story is everywhere in five minutes. What it changes for the machine is the part we add. The briefing + the essays →

FROM
THE DESK

There is no money in your bank account →

The essay layer: the balance in your app is a promise, not money — and that idea is the whole of payments. Read the essay →

JUN 30

Visa, Mastercard, Stripe and 140 others launch Open USD — a stablecoin that pays its distributors

Why it matters: stablecoins just discovered interchange — pay the distribution side and the volume follows. See: stablecoins →

JUL 01

UK's mandatory scam reimbursement turns one — fraud fell £73M, not rose

Why it matters: when banks own the loss, they fund the controls — and the US just started down the same path. See: fraud →

JUL 01

UK BNPL's grace period ends: register or stop lending, full FCA rules July 15

Why it matters: BNPL grew in the gap between credit products — the UK just closed its gap. See: BNPL →

Prashant Arya, founder of Tokens & Rails
WHO'S BEHIND THIS

Written by someone who works in the machine.

I'm Prashant — six years building payment products inside the industry. Tokens & Rails is the visual guide I always wanted and could never find.

Read the story →

One chapter a week,
drawn and animated.

Subscribe for new chapters, the fee calculator, and the payments quiz.

Subscribe for free →