The whole category in one page.
AUTHORISATION IS NOT SETTLEMENT
A successful payment does not mean you have the money. That gap — and the reserve, the fees and the disputes that follow — is where cash flow surprises live.
NO RESPONSE IS THE HARDEST CASE IN PAYMENTS
It is indistinguishable from success, failure and slowness. Record as pending, query by your own reference, and never assume failure and retry.
Idempotency keys derived from business intent are what make retries safe.
NEVER USE FLOATING POINT FOR MONEY, AND NEVER STORE A BALANCE AS A MUTABLE NUMBER
Immutable double-entry records, balances derived, and a daily check that the ledger sums to zero.
TRANSFERS DOMINATE THIS MARKET BECAUSE THEY ARE CHEAP, INSTANT AND FINAL
Which makes the recipient name returned by verification the last defence before money is gone for good.
RECONCILE THREE SOURCES DAILY, AND INVESTIGATE WHAT THE PROVIDER HAS THAT YOU DO NOT
CUSTOMER MONEY IS THEIRS
Safeguarding it separately is not a formality — using it is the failure that ends firms.
ESTABLISH THE REGULATED ACTIVITY FIRST, AND VERIFY CURRENT RULES DIRECTLY
Licensing categories, fee caps and product rules are revised regularly here. Building first and asking later has ended businesses.
