# LLM gateway security architecture: one enforceable boundary

URL: https://infro.io/blog/llm-gateway-security-architecture
Author: INFRO Editorial (https://infro.io/blog/editorial)
Publisher: INFRO
Published: 2026-08-03
Last modified: 2026-09-11
Last reviewed: 2026-09-11 (next review due 2026-12-10)
Topic: Security and governance
Format: Brief

> An LLM gateway is both a data-path dependency and a security enforcement point. A sound architecture minimizes retained content, scopes credentials, controls models and providers, protects logs, isolates tenants and environments, audits changes, and publishes the processors and policies buyers need to assess.

## Map the complete data path

Document application, gateway, provider routes, logs, analytics, support tooling, backups, and media storage. For each hop, identify data, purpose, region, encryption, retention, deletion, and access.

A gateway does not remove provider review; it should make the active provider path visible and reduce direct credentials in applications.

## Centralize enforceable policy

Use scoped keys, projects, roles, model allowlists, spend ceilings, rate controls, and environment separation. Apply policy before forwarding a request so disallowed data or models do not reach an upstream route.

Keep agent tool permissions separate. Permission to call a model is not permission to send an email, transfer money, or delete data.

## Protect operational evidence

Request traces are sensitive because metadata can reveal customers, features, and usage patterns even without prompts. Restrict access, redact secrets, choose retention deliberately, and audit privileged reads and policy changes.

Default to metadata-first logging and enable payload capture only for an approved debugging or evaluation purpose.

## Evaluate the vendor honestly

Review security documentation, DPA, subprocessors, incident process, vulnerability handling, deletion, availability, and current certifications. Test key revocation, model restrictions, error behavior, and log access.

Separate implemented controls from roadmap promises. Procurement needs the current state.

## Revision history

- 2026-09-11: Removed the promotional template sections and the generic FAQ, moved product context into the product section, and corrected product wording to the current BYOK model.