Open Banking APIs: How Aerapass Enables Third-Party Integration for Fintechs

Key Takeaways

• Open banking API transaction volumes are projected to exceed 580 billion globally by 2027, up from 102 billion in 2023 (Juniper Research).
• PSD2 in Europe, CDR in Australia, and Singapore’s APIX framework each define different API standards - fintechs operating across regions need a platform that abstracts these differences.
• OAuth 2.0 and FAPI (Financial-grade API) security profiles are the authentication standard for open banking, replacing screen scraping and credential sharing.
• Aerapass’s API-first architecture provides RESTful endpoints across payments, FX, card issuance, KYC, and portfolio management through a single integration.
• A single API connection to Aerapass replaces 4-6 separate vendor integrations for fintechs building multi-service financial platforms.

What Open Banking APIs Mean for Fintechs

Open banking is the regulatory and technical framework that allows third-party financial service providers to access banking data and initiate transactions through standardised APIs - with the customer’s explicit consent.

For fintechs, this is not an abstract concept. It is the infrastructure that determines what you can build, how quickly you can launch, and which markets you can enter. A fintech building a digital wallet in Singapore, a lending platform in Australia, and a payment aggregator in Europe needs API access to bank accounts, payment rails, identity verification, and FX services across all three markets. Without standardised APIs, each market requires bespoke integrations with individual banks - a model that does not scale.

The scale of the opportunity is substantial. Juniper Research projects open banking API transactions to exceed 580 billion globally by 2027, up from 102 billion in 2023. The fintechs that capture this growth are the ones with infrastructure that can connect to these APIs efficiently.

Open Banking API Use Cases: Functionality, Regulatory Basis, and Business Value

Use Case	Functionality	Regulatory Framework	Business Value
Account aggregation	Read-only access to customer account data across banks	PSD2 (EU), CDR (AU), MAS API guidelines (SG)	Single financial view for customers across institutions
Payment initiation	Initiate payments directly from bank accounts without cards	PSD2 PIS, FedNow APIs (US), FAST (SG)	Lower cost than card-based payments (no interchange)
Identity verification	Bank-verified identity for KYC onboarding	CDR (AU), PSD2 SCA (EU), eKYC (SG)	Reduced onboarding friction using bank-held data
Data enrichment	Transaction categorisation, income verification, affordability	PSD2 AIS (EU), CDR (AU)	Better lending decisions, personalised financial products
FX and cross-border	Real-time FX rates, multi-currency account access	MAS PSA (SG), FCA EMI (UK)	Transparent cross-border pricing without intermediaries
Balance and credit checks	Real-time balance verification before payment	PSD2 CBPII (EU), NPP (AU)	Reduced payment failures and returned transactions

Sources: European Banking Authority PSD2 technical standards (2024), Australian CDR rules (2025), MAS API Playbook (2024), Juniper Research Open Banking (2025)

The Regulatory Landscape: PSD2, CDR, and APIX

Open banking regulation varies significantly by market. Fintechs operating across regions must navigate three distinct frameworks.

Europe: PSD2 and PSD3 Transition

PSD2, in force since 2019, requires EU banks to provide API access to licensed third parties (AISPs and PISPs). The framework mandates Strong Customer Authentication (SCA) for payment initiation and establishes technical standards for API interfaces. PSD3, currently in legislative process, will address gaps in PSD2 including API performance standards, liability frameworks, and the extension of open banking principles to non-bank payment accounts.

Australia: Consumer Data Right (CDR)

Australia’s CDR framework goes beyond banking. It establishes a cross-sector data portability right that now covers banking, energy, and telecommunications. For fintechs, the banking CDR provides accredited access to transaction data, account balances, and product information through standardised APIs. The accreditation process is rigorous - requiring security assessments, insurance, and ongoing compliance.

Singapore: APIX and MAS Guidelines

Singapore’s approach is market-led rather than mandated. The ASEAN Financial Innovation Network’s APIX platform provides a sandbox for API-based financial services integration. MAS publishes API guidelines and encourages - but does not mandate - banks to provide open APIs. In practice, Singapore’s major banks (DBS, OCBC, UOB) offer extensive API suites, making the market functionally open without the regulatory compulsion of PSD2.

For a fintech building across all three regions, the challenge is not just technical compliance but architectural abstraction - the platform layer must translate between different API standards, authentication models, and consent frameworks without requiring separate codebases per jurisdiction.

Explore Aerapass fintech solutions →

Authentication and Security: OAuth 2.0 and FAPI

Open banking security has converged on two standards.

OAuth 2.0 provides the authorisation framework. The customer authenticates with their bank, grants consent to the fintech, and the bank issues an access token. The fintech never sees the customer’s banking credentials - only the scoped data the customer has consented to share.

FAPI (Financial-grade API) profiles build on OAuth 2.0 with additional security requirements specific to financial services: mutual TLS authentication, signed request objects, proof of possession tokens, and stricter redirect URI validation. FAPI is increasingly the baseline for open banking implementations in regulated markets.

For fintechs evaluating platform partners, the authentication architecture is a critical differentiator. Platforms that support FAPI-compliant authentication, dynamic client registration, and granular consent management reduce the compliance burden for each new market entry. Platforms that require custom authentication per integration create an engineering debt that compounds with scale.

Why API-First Architecture Matters

The distinction between “has APIs” and “is API-first” is not semantic. It determines what a fintech can build and how quickly.

A platform that has APIs bolted onto a legacy system exposes limited functionality through endpoints designed after the core system was built. Data models may not map cleanly. Real-time capabilities may be constrained by batch processing underneath. New features launch in the core system first and reach the API months later.

An API-first platform designs every capability as an API from the start. The API is the product. Internal and external consumers use the same endpoints. New capabilities are available via API on day one. The data model is designed for external consumption, with consistent naming, pagination, and error handling.

For fintechs building products that depend on a platform partner’s capabilities - payment processing, card issuance, KYC verification, portfolio management - this difference directly impacts development velocity and product reliability.

How Aerapass’s API Layer Works

Aerapass provides a unified API-first platform designed for fintechs, neobanks, and digital financial platforms. A single integration provides access to:

• Global payments - Multi-rail payment initiation, FX, and settlement across 120+ countries through RESTful endpoints
• Card issuance - Branded prepaid and debit card programmes with Mastercard and Visa scheme access via API
• Customer management - Digital onboarding, KYC verification, AML screening, and perpetual monitoring through a single endpoint
• Multi-asset exchange - FX, commodities, precious metals, and tokenised asset trading via API
• Wealth management - Portfolio management, reporting, and advisory tools for white-label deployment

The platform replaces the typical fintech integration stack of 4-6 separate providers (payment processor + card issuer + KYC provider + FX service + compliance engine + reporting tool) with a single API connection. This reduces integration complexity, vendor management overhead, and the compliance surface area.

All endpoints use consistent RESTful conventions, OAuth 2.0 authentication, webhook-based event notifications, and comprehensive sandbox environments for development and testing. Documentation, SDKs, and sandbox access are available through the developer portal.

For fintechs evaluating build vs buy decisions, the API architecture is the determining factor. The right platform partner provides institutional-grade capabilities through developer-friendly APIs - enabling fintechs to focus engineering resources on product differentiation rather than infrastructure.

Book a demo or explore the API →

Frequently Asked Questions

What is an open banking API?

An open banking API is a standardised interface that allows licensed third-party providers to access banking data and initiate transactions with the customer’s explicit consent. Rather than negotiating bespoke integrations with individual banks, fintechs connect through defined endpoints for account aggregation, payment initiation, identity verification, and balance checks. Juniper Research projects open banking API transactions to exceed 580 billion globally by 2027, up from 102 billion in 2023.

How do PSD2, CDR, and APIX differ?

PSD2 mandates that EU banks provide API access to licensed AISPs and PISPs, with Strong Customer Authentication required for payment initiation. Australia’s Consumer Data Right is a cross-sector data portability regime covering banking, energy, and telecommunications, with a rigorous accreditation process. Singapore’s approach is market-led rather than mandated: MAS publishes API guidelines and the APIX platform provides a sandbox, but banks are not compelled to open their APIs - though DBS, OCBC, and UOB offer extensive API suites in practice.

What security standards do open banking APIs use?

OAuth 2.0 provides the authorisation framework: the customer authenticates with their bank, grants scoped consent, and the bank issues an access token, so the fintech never sees banking credentials. FAPI (Financial-grade API) profiles build on OAuth 2.0 with mutual TLS authentication, signed request objects, proof of possession tokens, and stricter redirect URI validation. FAPI is increasingly the baseline for open banking in regulated markets, replacing screen scraping and credential sharing.

What is the difference between an API-first platform and one that has APIs?

A platform that has APIs bolted onto a legacy system exposes limited functionality through endpoints designed after the core system was built, with data models that may not map cleanly and real-time capabilities constrained by batch processing underneath. An API-first platform designs every capability as an API from the start - the API is the product, internal and external consumers use the same endpoints, and new capabilities are available on day one. For fintechs, this difference directly affects development velocity and product reliability.