API-Driven Treasury: How to integrate your TMS with ERPs and Banks

As finance temas evolve from manual, file-based operations to real-time data-driven environments, one technology is quietly reshaping the backbone of financial connectivity: APIs (Application Programming Interfaces). For years, finance teams have been forced to rely on SWIFT files, SFTP servers, and nightly batch updates. Today, APIs are enabling instant access to cash positions, real-time payment execution, and seamless data flows between systems. The result? Faster decision-making, better control, and radically improved operational efficiency.

But what does it actually mean to “connect your TMS to your ERP and your banks via API”? In this article, we’ll break down the API building blocks of a modern treasury stack, explain how to integrate them, and share a real-world example of what this looks like in action.

What are APIs and why do they matter for treasury?

APIs are software interfaces that allow different systems to “talk” to each other in real time. Think of them as the pipes that connect your treasury plumbing: your ERP (where transactions originate), your TMS (where liquidity and risk are managed), and your banks (where cash is held and moved). Instead of uploading files or sending emails, APIs enable direct, instant communication between these systems.

In treasury, this means:

• Pulling live account balances from banks into your TMS
• Initiating payments directly from your ERP
• Receiving real-time status updates on FX trades
• Automating bank reconciliation and cash forecasting

APIs reduce manual errors, enhance visibility, and provide agility in responding to market changes — all of which are critical in today’s volatile financial environment.

Building blocks of the API-driven treasury

To understand API integration, let’s break the treasury tech stack into three parts:

1. ERP (Enterprise Resource Planning)

This is your accounting system — SAP, Oracle, Microsoft Dynamics, Netsuite , etc. — where invoices, payroll, and vendor payments originate.

2. TMS (Treasury Management System)

This is the control tower for treasury. It manages cash flow forecasting, FX risk, intercompany loans, and bank account visibility.

3. Banks and Financial Institutions

These are your cash custodians. Banks offer APIs for balance reporting, payment execution, transaction notifications, and FX services.

APIs connect these three layers, enabling a seamless data exchange between operational finance (ERP), strategic decision-making (TMS), and execution (banks).

How to Integrate: TMS ↔ ERP ↔ Bank

A typical API integration follows this flow:

Step 1: ERP to TMS

Your ERP sends payment proposals, forecasted cash flows, and invoice data to your TMS via API. This helps the TMS consolidate positions and project liquidity across time horizons.

Step 2: TMS to Bank

The TMS sends validated and approved payments, FX deals, or sweeping instructions to your bank via its corporate API. Banks respond instantly with confirmations, reference numbers, or error messages.

Step 3: Bank to TMS (and ERP)

Your TMS receives real-time balance and transaction data from each bank account via API. This data can also be passed to the ERP for reconciliation and reporting purposes.

Together, this closed loop allows treasurers to manage cash, risk, and payments from a single interface — without ever exporting a file.

Security & Compliance Considerations

When integrating APIs in treasury, data protection and access control are essential. Key areas to focus on:

• Authentication: Use secure methods like OAuth2 or mutual TLS to control access.
• Consent & Access Rights: PSD2 APIs require explicit user consent; corporate APIs use predefined credentials with scope limits.
• Data Privacy: Ensure compliance with GDPR and other data regulations — both in transit and at rest.
• Auditability: Maintain logs of all API activity for transparency and internal control.
• Cybersecurity: Coordinate with IT and InfoSec teams to assess API endpoints and enforce secure integration standards.

In short, treat APIs like opening a digital vault: only the right people and systems should ever get the key.

Best Practices for API-Driven Treasury Projects

Implementing API integrations doesn’t have to be a chaotic and complex project. Follow these principles for a smooth rollout:

• Start with a focused use case: E.g., retrieving daily bank balances from 10 banks, or automating payroll execution via ERP.
• Choose API-native vendors: Ensure your TMS and ERP can natively support open API standards (like REST and JSON).
• Modular rollouts: Tackle one process at a time — e.g., start with balances, then move to payments and reconciliation.
• Collaborate cross-functionally: Involve treasury, IT, InfoSec, and compliance early to align expectations and responsibilities.

Real-World Example: Embat + ERP + Banks

A European technology company using Embat’s TMS integrated its ERP (Netsuite) and two main banking partners via API. The project enabled the following:

• Automated daily balance retrieval across 12 accounts via BNP Paribas and Citi APIs
• Direct payment execution from Netsuite through Embat to bank APIs with real-time status updates
• Cash flow forecasting enriched by ERP data on payables and receivables, updated hourly

The result: 90% fewer reconciliation errors, cash visibility by 9:00am every day, and real-time FX rate validation before settlement. What used to take hours and emails now happens automatically, every day.

Conclusion

APIs are no longer a buzzword — they are the foundation of a modern treasury infrastructure. By connecting your TMS, ERP, and banks through APIs, you enable faster, smarter, and more secure treasury operations. Whether you’re a multinational or a fast-scaling startup, building an API-first treasury stack is the next logical step toward efficiency, agility, and control.

Now is the time to assess your systems, talk to your banks, and start building the infrastructure of tomorrow — today.