Sebastien Rousseau

PAYMENTS

SWIFT

Messaging, GPI, payment pre-validation, and SWIFT's evolving role in the multi-rail world.

9 articles

PAYMENTS & MONEY

From Messages to Map: Building a Global Corporate Standard on ISO 20022 and Swift

The industry finally has a global language for payments. It still does not have a global map for corporates to act on it. ISO 20022 and Swift's CBPR+ harmonised what a payment must say, not how a corporate uses it — the missing interface and behaviour layers, and how banks can build a global corporate standard on the rails they already have.

APPLIED AI

From Fragmentation to Fault Line: Corporate Banking's Missing API Standard in the Agentic Era

Retail banking got its API standard a decade ago. Corporate banking never did — and now that AI agents and the Model Context Protocol have turned integration into a runtime decision, the gap has stopped being a nuisance and become a fault line. A concrete failure mode, the strategic choice it forces, and what a corporate banking API standard has to mandate.

PAYMENTS & MONEY

Cross-Border 2026: ISO 20022, Open Finance and Tokenised Deposits in Corporate Treasury

Cross-border corporate treasury in 2026 is a multi-rail engineering problem. ISO 20022 is the common grammar, A2A and open finance under PSD3/FiDA are the customer-facing rail, tokenised deposits handle the wholesale settlement leg, and SWIFT still anchors the long tail. The interesting work is in the orchestration layer, not the model.

APPLIED AI

From Pain.001 to Programmable Liquidity: ISO 20022 as the Autonomic Nervous System of Treasury in 2026

ISO 20022 in 2026 is the autonomic nervous system of treasury. pain.001 and pacs.008 carry richer data than any MT message ever did. Nearly half of banks remain off-track for the November 2026 SWIFT MT/MX cut-over, structured addresses become mandatory, and agentic treasury cannot exist without MX-native APIs. This article maps the engineering reality, from CBPR+ validation rules to a real pain.001 fragment with PstlAdr fields.

APPLIED AI

Post-Quantum Payments Infrastructure: Why Banks May Replace Rather Than Retrofit Legacy Rails

Harvest-now-decrypt-later turns today's TLS-protected payment messages into tomorrow's decrypted exposure. ML-KEM and ML-DSA are an order of magnitude larger than the RSA and ECC keys legacy rails were sized for — retrofit triggers fragmentation, latency, and HSM exhaustion. The 2026 architectural decision is whether to patch or replace before the regulatory clock runs out.

APPLIED AI

Quantum-Safe Payments: Why the Industry Must Act Now

Modern payment infrastructure relies on public-key cryptography. RSA, ECC, and Diffie-Hellman. To authenticate transactions, protect cardholder data, and secure messaging between financial…

APPLIED AI

Automating ISO 20022 Payment Files Creation with pain001

pain001 is an open-source Python library that generates ISO 20022 pain.001.001.09 (CustomerCreditTransferInitiation) XML from CSV or SQLite input, validates output against the XSD schema, and computes CtrlSum and NbOfTxs automatically — supporting both SEPA SCT and CBPR+ cross-border message formats.