Question: I'm looking for a scalable and reliable payment engine that can handle high-risk and complex billing for my online store.

If you're looking for a scalable and reliable payment engine that can handle high-risk and complex billing for your online store, sticky.io is an excellent choice. They specialize in managing high-risk and complex billing, offering advanced payment routing, better risk mitigation, and multiple payment methods. It's used by over 10,000 merchants who process more than $8 billion annually and integrates with over 400 third-party tools.

Another strong option is ACI Worldwide. This platform supports various payment needs, including fraud management through responsible AI. It's designed to handle high transaction volumes and can be deployed in various ways, such as licensed software, SaaS, or hybrid models. It serves a global client base and processes over 250 billion transactions each year, making it a reliable choice for high-volume payment processing.

Inai offers a full-stack payment platform that simplifies payment operations with a single API connecting to multiple payment service providers. It includes tools for detailed transaction analysis, payment workflow automation, and end-to-end reconciliation. Inai can handle high transaction volumes with 99.99% uptime, making it suitable for businesses aiming to lower payment failure rates and increase revenue.

For those requiring a modular approach, Mangopay provides a suite of payment infrastructure products tailored for marketplaces and platforms. It includes e-wallet management, identity verification, and AI-powered fraud prevention, supporting various use cases like C2C and B2B platforms. With prebuilt integrations and APIs, Mangopay offers flexibility and efficiency in managing payment lifecycles, ensuring reliability and compliance.