Gartner Expert

Mark O'Neill

VP Analyst

Mark O'Neill advises on API strategy, including API management and building API products. His coverage includes API security, and how API security relates to application firewalls and identity and access management. He also covers API-based integration and how this relates to ESB and integration products.

Mr. O'Neill also advises on strategy for banking APIs, including open banking.

Previous experience

Mr. O'Neill is the author of the book "Web Services Security" and other guidance on API security and strategy. He began his career at an EDI VAN (value-added network) where he extended B2B networks securely to use the internet. He then co-founded two companies, acting as CTO at both, leading to both companies being acquired. At Vordel, as CTO, he drove SOA gateway strategy.

Throughout his career, Mr. O'Neill has worked closely with enterprise architects, CIOs and security professionals, providing best-practice architecture for engaging with the API economy, including API monetization strategy, API security strategy and full life cycle API management.

Professional background


VP Innovation


CTO and Co-founder

Delphium Technologies

CTO and Co-founder

Areas of coverage

Applications and Software Engineering Leaders

Software Engineering Technologies

Software Engineering Strategies


B.A., Mathematics and Psychology, Trinity College, Dublin

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Top Issues That I Help Clients Address

1API management including API gateways and API portals

2API security using standards such as OAuth and OpenID Connect

3API integration with iPaaS and ESB

4Banking APIs, including PSD2

5Microservices architecture, service mesh, and how it relates to APIs and SOA