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Payment Lifecycle 101 — New Learner Guide

Welcome to Payments​

If you're new to banking, the payment ecosystem can feel overwhelming. This page takes you from zero to "I understand how a payment works" using plain language and diagrams — no assumptions about prior knowledge.

The Big Picture: What Happens When You Pay Someone?​

You open your banking app, type $500 and your friend's BSB + account number, and hit "Send". Simple, right? Under the hood, a surprisingly complex sequence of events occurs in under 15 seconds.

YOU                     YOUR BANK               YOUR FRIEND'S BANK      YOUR FRIEND

Tap "Send" ────────────►│                               │                     │
                         │  1. Is this really you?       │                     │
                         │  2. Do you have $500?         │                     │
                         │  3. Is this payment risky?    │                     │
                         │  4. Debit your account $500   │                     │
                         │────── Send payment ──────────►│                     │
                         │                               │  5. Is this legit?  │
                         │                               │  6. Find account    │
                         │                               │  7. Credit $500     │
                         │◄──── Confirmed ───────────────│────── Notify ──────►│
                         │                               │                "You received $500"
                         │
                    "Payment sent"

Every single one of those numbered steps is a system, a rule, or a protocol. This guide explains each one.

Step 1 — You Initiate a Payment​

You provide:

  • How much — $500
  • Who to — BSB 062-000, Account 12345678
  • Why — "Rent for June"

Your bank calls this a payment instruction or payment order.

In the ISO 20022 world (the international standard banks use), the electronic version of your instruction is a pain.001 message (see pain.001).

Step 2 — Authentication & Authorisation​

Before anything happens, your bank asks:

"Is this really you, and are you allowed to make this payment?"

CheckWhat it does
AuthenticationConfirms you are who you say you are (PIN, biometric, OTP)
AuthorisationConfirms you're allowed to send from this account in this amount

Step 3 — Can You Afford It?​

Your bank checks your available balance:

Ledger Balance:    $1,200    (total of all posted transactions)
− Existing Holds:  $200      (e.g., pending card payment)
= Available:       $1,000

Payment amount:    $500      ✅ Sufficient

If you don't have enough: payment is declined immediately, before anything else happens.

Step 4 — Screening (The Compliance Checks)​

This is the step most people don't know exists. Before a single dollar moves, the bank runs:

Duplicate Check​

"Did we already process this exact payment?" — Prevents accidental double-payments.

Sanctions Screening​

"Is the recipient on a government prohibited list?" — e.g., OFAC, UN sanctions lists. If yes: payment is blocked, compliance team alerted.

Fraud Assessment​

"Does this payment look suspicious?" — Rules + AI models analyse hundreds of signals. If risky: payment may be held for review or a challenge (OTP) sent to you.

AML Check​

"Does this fit a money laundering pattern?" — Velocity rules, structuring detection.

👉 See Fraud, Sanctions, AML & KYC

Step 5 — Debit Your Account​

Once all checks pass, your bank:

  1. Reserves the $500 (reduces your available balance)
  2. Eventually posts a debit — a formal ledger entry saying "Account 9999 sent $500"
  3. Sends you a debit notification (that push notification: "Payment sent: $500")

The notification is generated from a camt.054 message — see camt.054.

Step 6 — Route the Payment​

Your bank decides which rail to use to deliver the money:

Same bank as recipient? ─────► On-Us (internal transfer, instant)

Different bank? ───────────────► Which scheme?
  Real-time (NPP)?  ─────────── NPP / Osko (< 15 seconds)
  High value?       ─────────── RTGS (same day)
  Bill payment?     ─────────── BPAY (next day)
  International?    ─────────── SWIFT (1–2 days)
  Otherwise?        ─────────── BECS Direct Entry (next day)

👉 See NPP, BPAY, SWIFT, and Clearing & Settlement

Step 7 — The Interbank Message​

Your bank now tells your friend's bank about the payment using a standard message format: pacs.008 — the interbank credit transfer. This message contains:

  • Your details (name, account)
  • Your friend's details (name, account)
  • The amount
  • A unique ID to track the payment end-to-end

👉 See pacs.008

Step 8 — Settlement (The Money Actually Moves)​

The pacs.008 is information — it says "I'm sending you $500". But actual money doesn't flow through that message. It flows through a settlement system:

For NPP:   RBA Fast Settlement Service (FSS)
           Reserve Bank debits your bank's settlement account
           Reserve Bank credits your friend's bank's settlement account
           This is FINAL — irrevocable, real money

For BECS:  End of day netting
           All payments between banks are netted
           Only the difference settles at the RBA

👉 See Clearing & Settlement

Step 9 — Credit Your Friend's Account​

Your friend's bank:

  1. Receives the pacs.008
  2. Runs its own screening (fraud, sanctions)
  3. Identifies your friend's account
  4. Credits $500 to your friend's account
  5. Sends your friend a credit notification (camt.054)

Step 10 — Confirmation​

Your bank receives confirmation that the payment was successfully processed (pacs.002). Your app updates: "Payment delivered ✅"

What Could Go Wrong? (Exceptions)​

Payments don't always complete smoothly:

ProblemWhat Happens
Wrong account numberYour friend's bank can't find the account → Returns funds via pacs.004
Sanctions matchPayment blocked → Compliance team review
Fraud detectedPayment held → You receive a call or challenge
Network outagePayment queued → Retried when network recovers
Insufficient fundsDeclined immediately → No funds moved

👉 See Payment Exceptions, pacs.004

Full Message Sequence (NPP Payment)​

Here's every message exchanged for a successful NPP payment:

You (Customer)         Your Bank              Their Bank         Your Friend

pain.001 ────────────►
(optional, for API/
 corporate; usually
 just API call)

                       pacs.008 ─────────────►
                       (interbank message)

                                              Credit account
                                              ◄──── pacs.002 ────
                                              (confirmed)

◄──── camt.054 ─────                                             ◄──── camt.054
(Debit notification)                                             (Credit notification)

                       ◄──── pain.002 ─────
                       (status from network,
                        for corporate customers)

Key Terms Cheat Sheet​

TermPlain English
DebtorThe person paying (money leaves their account)
CreditorThe person receiving (money enters their account)
Debtor BankThe payer's bank — sends the payment
Creditor BankThe payee's bank — receives the payment
ClearingExchanging payment information between banks
SettlementThe actual movement of money between banks
ESAA bank's account at the Reserve Bank (where settlement happens)
BSB6-digit code identifying a branch in Australia
PayIDA phone number or email linked to a bank account
pacsPayment Clearing and Settlement — ISO 20022 interbank messages
painPayment Initiation — ISO 20022 customer-to-bank messages
camtCash Management — ISO 20022 bank-to-customer messages
NPPNew Payments Platform — Australia's real-time payment network
STPStraight-Through Processing — payment completed without human intervention

Based on your role:

🧑‍💻 Developer / Engineer​

  1. pain.001 → pacs.008 → camt.054 — the message chain
  2. On-Us vs Off-Us — routing logic
  3. NPP — the main AU real-time scheme

🔍 Analyst / Operations​

  1. Inbound Payments → Outbound Payments
  2. Payment Exceptions
  3. Reconciliation

🛡️ Compliance / Risk​

  1. Sanctions Screening
  2. AML & KYC
  3. Fraud Detection

📊 Product / Business​

  1. NPP, BPAY, and SWIFT — understanding the rails
  2. NPP & PayTo — modern AU payments
  3. Open Banking / CDR — future of payments