Agentic trading gateways are the integration layers that let autonomous AI agents place, monitor and settle trades — either by interacting directly with blockchains (on‑chain) or by using centralized exchange APIs (CEX). Choosing between them requires balancing latency, custody, liquidity and attack surface. On‑chain gateways give verifiable settlement, programmable custody and composability with smart‑contract primitives, but expose agents to smart‑contract bugs, MEV/front‑running risks and higher finality latency (mitigated by L2s and rollups). CEX gateways deliver low latency, deep liquidity and familiar API controls but introduce counterparty and custody risk and opaque internal matching or liquidation behaviors. This topic is timely in 2026 because AI agent frameworks and no‑code agent platforms have matured (LangChain, AutoGPT, AgentGPT, MindStudio) and developer tooling (Replit, Cursor, JetBrains AI Assistant) plus quality and governance tooling (Qodo) are accelerating production deployments. Those tools shape how agents are authored, tested and deployed into marketplaces or trading chatbot front ends. Emerging custody patterns — MPC/threshold signatures, custody tokenization, and hybrid on‑chain settlement — create new gateway designs that try to combine the low latency of CEXs with verifiable settlement properties of blockchains. Practically, teams must evaluate threat models (exchange insolvency, smart‑contract exploits, oracle/manipulation, MEV), performance needs (microsecond order routing vs periodic rebalancing), compliance and auditability, and the maturity of agent testing/governance pipelines. The most robust architectures in 2026 are hybrid: off‑chain execution engines for latency‑sensitive decisions with on‑chain settlement or cryptographic attestations for custody and audit. Tooling choice should emphasize reproducible testing, runtime controls and clear custody boundaries rather than convenience alone.