Curation in progress
Payments
Seven modules on the layer a product needs the moment it has a customer, and the only one where being wrong costs money rather than uptime. What authorization, capture, settlement and payout actually are and who is entitled to decline each of them. How you become someone allowed to take a payment at all, and whether you want a gateway or a merchant of record. What a checkout hands to an attacker. Then the part nobody sequences: minor units, the webhook that is the only thing that knows, idempotency, entitlement state and a double-entry ledger that reconciles. Subscriptions on a card and under India's e-mandate framework. Declines, dunning, refunds and chargebacks. Marketplaces, splits and payouts. And what spending authority an AI agent may be granted.
- Modules
- 7
- Lessons
- 35
- Watch time
- 14h 46m
- Free to open
- 14
How Money Actually Moves
Separate the four different events that 'the payment went through' collapses into one, and learn who in the chain is entitled to say no.
- 01.01What Happens When Someone PaysName authorization, capture, settlement and payout as four separate events, and say how many days can pass between the first and the last.
- 01.02Who Says No, and WhyPlace the merchant, gateway, processor, acquirer, network and issuer in order, and say which one actually decides whether a payment is approved.
- 01.03Cards, UPI, Wallets & Bank TransfersExplain the difference between a payment you pull and a payment the customer pushes, and say why a UPI collect request is not a card authorization and never becomes one.
- 01.04What a Payment Costs YouBreak a headline rate into interchange, scheme fee and processor markup, and say why UPI merchant transactions in India carry no such rate at all.
- 01.05Every State a Payment Can Be InDraw the state machine a single payment moves through, and say why pending is not a failure and why failed is not always final.
Becoming a Merchant & Choosing the Stack
Answer 'which provider' only after answering what kind of money flow this is, where it starts, where it lands, and who is legally selling.
- 02.01Gateway, Processor or Merchant of RecordDistinguish the three things people call 'a payment provider', and say which one changes who the legal seller is.
- 02.02The Tax You Stop OwingSay what sales tax, VAT and GST obligations a merchant of record absorbs, what it does not absorb, and what nexus means for a seller who has never left home.
- 02.03Selling From IndiaChoose a rail for an Indian entity taking money from abroad, and name the licence, the code and the certificate that decide whether you can.
- 02.04Selling to the WorldSeparate the currency a customer is shown from the currency you are paid in, and explain how a rupee sale gets reported as a dollar one.
- 02.05The Account You Cannot GetDescribe what a provider is underwriting when it onboards you, and name three legitimate businesses that will be refused an account anyway.
Checkout & the First Payment
Take one real payment, and know exactly which parts of it an attacker controls.
- 03.01Hosted, Embedded, or Your Own FormChoose between a redirect, an embedded element and your own card form, and say what each choice does to the PCI questionnaire you have to answer.
- 03.02The Amount Must Never Come From the BrowserIdentify every field in a checkout request that the client controls, and move price, plan and identity to the server before an attacker moves them for you.
- 03.03Intents, Authorization & CaptureBuild a checkout that survives a customer closing the tab and coming back, by reusing one payment intent instead of creating a second.
- 03.04What a Checkout Page LosesName the four checkout decisions that move conversion most, and say why the right payment methods matter more than the page design.
- 03.05Test Mode Is a Different PlanetExercise the whole money path against a sandbox, including replayed webhooks, and list what is still untested the moment you switch on live keys.
Money in Your Database
The module this subject is actually about: what has to be true in your own tables before you are entitled to call an order paid.
- 04.01Never Store Money in a FloatStore an amount as an integer in its currency's minor unit, and handle the currencies that have three decimal places or none.
- 04.02The Webhook Is the Only Thing That KnowsProvision access from a verified server-side event rather than from a browser redirect, and say why a customer who closes the tab must still get what they paid for.
- 04.03Idempotency, or You Will Charge TwiceMake a webhook handler safe to run twice on the same event, and explain why at-least-once delivery makes that a requirement rather than a precaution.
- 04.04The Entitlement State MachineModel what a customer is entitled to as its own state, separate from the payment that granted it, with grace, expiry and revocation as distinct transitions.
- 04.05The Ledger and the Monthly CloseRecord money with double-entry, append-only writes committed in one transaction, and reconcile your own numbers against the processor report and the bank.
Subscriptions, Usage & Recurring Money
Money that arrives again without anyone clicking anything, on two rails that authorise it in completely different ways.
- 05.01What a Subscription Actually IsSeparate the mandate from the charge and the invoice, and say which object owns the amount your customer will be billed.
- 05.02Recurring in IndiaSet up a recurring charge under the RBI e-mandate framework, and name the authentication step, the value threshold and the notice period it forces on you.
- 05.03Trials, Coupons, Proration & UpgradesChange a customer's plan mid-cycle and charge the right amount, and put a discount where the amount is computed rather than where it is displayed.
- 05.04Usage Billing, Credits & OveragesMeter what a customer consumed and turn it into an invoice they trust, with credit blocks that expire and burn in a defined order.
- 05.05Dunning, Cancellation & the EndDesign what happens over the days after a renewal fails, and keep cancelling a subscription from being the same event as revoking access.
Failure, Fraud & Disputes
The declines that were recoverable and you lost anyway, and the money that gets taken back after you have already delivered.
- 06.01Why Good Customers Get DeclinedTell a soft decline from a hard one, and say which of them you may retry and which you must never retry.
- 06.023DS, SCA & the Soft Decline You Must EscalateExplain when strong customer authentication is required and when it is exempt, and recover a transaction the issuer soft-declined instead of losing it.
- 06.03Fraud, Card Testing & Risk RulesRecognise a card-testing attack running against your own checkout, and set a risk threshold knowing what it costs you in real customers.
- 06.04Refunds, and What They Do Not UnwindIssue a full or partial refund, then list every other thing in your system that a refund did not touch and has to be undone by hand.
- 06.05Chargebacks & the Evidence That WinsRespond to a dispute with the evidence that actually decides it, and say what your dispute ratio costs you before anyone has won or lost.
Platforms, Payouts & the Agentic Money Path
Money that passes through you on its way to somebody else, and money spent by something that is not a person.
- 07.01When the Money Is Not YoursDescribe how a platform's architecture differs from a shop's, and say who the merchant legally is once a third party is being paid.
- 07.02Splits, Commissions & Seller KYCSplit one payment between a seller, your commission and the fees, and say what you must verify about a seller before you are allowed to pay them at all.
- 07.03Payouts, Reserves & the Float You Are HoldingDesign a payout schedule with a reserve, and explain why a balance you are holding for other people must reconcile to the account underneath it every single day.
- 07.04Agents That Spend MoneyExplain how an agent is granted a bounded authority to pay rather than a card, and name the two protocols competing to define what that grant looks like.
- 07.05The Payment Code Your Agent WroteAudit a generated payment integration against this course, and find the missing pieces in the handler rather than in the provider call that looks correct.