The second tier of Telecom Application Programming Interface (API) market taxonomy classifies APIs by type, which determines integration complexity, performance characteristics, and pricing models. RESTful APIs dominate with an estimated 55 % share, owing to their lightweight HTTP‑based design, JSON payloads and broad developer adoption across carrier portals and digital services. SOAP APIs, still prevalent in legacy OSS/BSS environments for their strict contract‑first approach, account for roughly 20 % of deployments, especially where WS‑Security and transaction reliability are mandatory. GraphQL, a newer query‑language layer, captures about 8 % as operators seek granular data retrieval for analytics dashboards. Webhook‑driven event APIs, enabling push‑based notifications for real‑time usage alerts and network‑state changes, represent 7 % of the mix. SDK bundles (software development kits) that wrap API calls for specific platforms—iOS, Android, Java—contribute 5 %, facilitating rapid app creation for MVNOs and enterprise customers. Finally, micro‑gateway and API‑management platforms, which provide policy enforcement, throttling and monetization, occupy the remaining 5 %, reflecting growing emphasis on security and monetization frameworks. These type‑based distinctions collectively shape procurement strategies and revenue streams within the Telecom API market.