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How do you enable hundreds of online transactions per second?
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Some of the world’s busiest e-commerce platforms rely on leading Payment Service Provider Worldline every day. During peak moments, that trust translates into hundreds of transactions flowing through the platform every second. It’s a level of scale that leaves no room for friction — user experience has to feel effortless, integrations need to be straightforward, and reliability must be absolute.
iO helped Worldline turn that complexity into clarity. Not just by making scale technically possible, but by making it intuitive for developers and reassuringly safe for merchants. By improving the UX and DX of the Worldline Connect platform, we designed and delivered a new integration layer, modern payment pages, an API explorer, and hands-on developer support through a dedicated developer portal.
Optimized UX and DX
Design and implementation of a new integration layer, payment pages, API explorer, and developer portal
A stable solution built to comply with modern security standards
Global support for more than 100 payment products
Successful LLM and AI integrations
A global platform with 100+ payment methods
With a global presence and support for more than 100 payment methods — from Mastercard and PayPal to Google & Apple Pay, WeChat Pay, and Boleto Bancario — Worldline helps merchants do business anywhere in the world. Built on years of hands-on experience and ongoing investment, the platform has grown into a trusted partner in global commerce.
For merchants and developers alike, it’s no longer just about offering the right payment methods. It’s about how easily they can be set up and how confidently they can scale. The simpler and more secure the integration, the faster businesses can move into new markets and keep growing.
Challenge
Optimizing the UX and DX of a global platform.
Solution
Designing and implementing a new integration layer, modern payment pages, an API explorer, and a developer portal that enable fast, secure, and scalable integrations.
About Worldline
Worldline is a leading global player in secure payments and trusted transaction processing. Its innovative online payment solutions are accessible to everyone, support sustainable economic growth, and strengthen trust in secure payment options such as credit cards, direct banking, and online wallets.
Secure online payments built on modern security standards
After a meticulous vendor selection process, Worldline partnered with iO to improve the platform’s ease of integration and mobile support: the Worldline Connect project. For a globally operating Payment Service Provider, this means dealing with multiple currencies, regional payment methods, and complex transaction flows.
We built a new, streamlined REST API that forms the backbone of every integration, making it easier for developers to get up and running. To keep things responsive and transparent, we paired it with a modern webhooks architecture that delivers real-time payment status updates without adding complexity.
Together with Worldline’s payment specialists, we shaped new API definitions and designed responsive payment pages that work seamlessly across devices. The resulting MyCheckout service is especially valuable for merchants who want to reduce their exposure to the strict PCI DSS standard. Performance, A/B testing, mobile security, and conversion optimization were core design principles from day one.
For native mobile apps, we developed SDKs (Software Development Kits) that allow developers to easily integrate Worldline’s rich set of payment products. We also built SDKs for e-commerce platforms in PHP, Node.js, and Java, enabling common setups to be tested and implemented quickly.
The result: less implementation time, better documentation, and a faster time to market.
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A scalable payment API and developer portal for fast integration
A payment API gateway has to earn trust at scale. Hundreds of transactions need to be processed securely every second, while the platform continues to grow and adapt to new regions and markets around the world.
After the initial releases of Worldline Connect, the focus shifted to bringing payment products from around the world together behind the new Connect API. This allowed Worldline to rapidly expand its offering in regions such as India and South America. Despite the technical complexity, existing merchant integrations remained completely unaffected, thanks to the API’s robust and future-ready architecture.
Clear API documentation plays a crucial role in the developer experience, just like access to a sandbox environment. That’s why we delivered:
a central developer portal with clear API documentation and SDKs;
a comprehensive API explorer for testing and validation;
a scalable data architecture focused on performance and stability.
The result? Faster onboarding, fewer integration errors, and a future-proof payment platform.
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AI in payments: agentic commerce and LLM integrations
How do you make payment functionality accessible to AI assistants and LLM clients?
With the rapid rise of AI and Large Language Models (LLMs), we explored with Worldline how the existing API landscape could be opened up to a new generation of clients: AI agents and LLM-based applications.
Worldline sees clear potential in agentic commerce — think shopping experiences powered by tools like ChatGPT — and chose to act early. As Worldline’s technology partner for more than a decade, we built the merchant-facing API ecosystem from the ground up. In this next phase, we carefully and securely opened that same ecosystem to AI-driven applications.
This approach yielded new sales channels, automated processes, and a solid foundation for the next generation of e-commerce.
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Two practical use cases for payment automation
Together with Worldline, we defined two scenarios where LLM integration delivers immediate value:
AI assistant for consumers (agentic commerce)
Merchants can offer their customers an AI assistant that helps them discover and choose the right products in the webshop. When it’s time to check out, the assistant seamlessly creates a secure checkout link through the Worldline APIs.
AI assistant for merchants (transaction management)
Merchants can use an AI agent to handle payments, whether it’s for approving, canceling, or refunding transactions. Tasks that used to require custom interfaces can now be managed smoothly and securely through AI-powered agents.
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Technical implementation: secure LLM integration with payment APIs
To bring these AI use cases to life, we built applications using the Model Context Protocol (MCP) that open up Worldline’s APIs to LLM clients and AI agents. Every request is securely authenticated, and AI-driven instructions are seamlessly translated into standard Worldline API calls, making complex processes feel effortless.
Alongside the tech aspect, we worked together with Worldline to create crystal-clear documentation, showing exactly what’s possible and how LLM clients or agents can connect safely. These applications run on Google Cloud Platform (GCP), Worldline’s new strategic cloud home. They’re the first of their kind in this division: a major step in the company’s cloud transformation and a foundation for future innovation.
Because this solution introduces a whole new access layer and relies on a cutting-edge protocol, it underwent a rigorous security audit, with extra safeguards to keep merchant data fully protected.
The outcome? Merchants can now drive API actions from any LLM client — like Claude Desktop — and create intelligent AI agents that automate payment processes, opening the door to faster operations, smarter workflows, and the next generation of commerce.
Cloud transformation with AWS: scalable infrastructure for global payments
Working closely with AWS, we partner with Worldline to create ever smoother, more secure cloud integrations. With the global reach of both Worldline and AWS, computing power and data storage can be deployed where they’re needed most, optimizing performance by region. As an AWS Select Partner, we’re deeply involved in re-platforming, re-engineering, and automating the full delivery pipeline, helping Worldline scale faster and operate more efficiently worldwide.
Want to know how we can put all this into practice for you?
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