API management covers gateways that route and secure API traffic, tools for publishing and versioning APIs, developer portals, and API security and monitoring. Organisations use them to expose services to partners and applications, to apply authentication, rate limiting and quotas centrally, and to keep an inventory of what is exposed.
A gateway terminates traffic in front of your services, so tokens, keys and request payloads pass through it in clear text, and a hosted control plane can see how your systems talk to each other. Where the gateway runs and who operates it therefore determines who can observe or interrupt critical flows. Lock-in tends to sit in vendor-specific policy languages, plugins and portal customisations that must be rebuilt when you move. OWASP's API Security Top 10 lists risks such as broken authorisation, unrestricted resource consumption and improper inventory management, areas a gateway should help control.
When choosing a European option, look at whether the gateway can run in your own cloud or on-premises with a control plane you also host, whether it supports standard specifications such as OpenAPI, how keys and secrets are stored, how logging can be limited to what you need, and whether the core is open source so configuration can move with you.