--- title: "Microsoft Entra App Proxy vs GuardianKey AuthBastion — GuardianKey" source_url: "https://guardiankey.io/posts/microsoft-entra-app-proxy-vs-guardiankey-authbastion/" language: "en" description: "Microsoft Entra App Proxy vs GuardianKey AuthBastion: Modernization Without Rewriting Apps. A practical comparison for teams evaluating Microsoft Entra App Proxy and GuardianKey AuthBastion." lastmod: "2026-05-14T13:43:02+00:00" --- # Microsoft Entra App Proxy vs GuardianKey AuthBastion — GuardianKey [GuardianKey](https://guardiankey.io/)/Authentication Bastion COMPARISON AuthBastion # Microsoft Entra App Proxy vs GuardianKey AuthBastion *Modernization Without Rewriting Apps.* GuardianKey AuthBastion and Microsoft Entra App Proxy can both improve security outcomes, but they usually enter the architecture for different reasons. This article compares the decision through scope, deployment model, user friction, and operational control. [Request a demo →](https://guardiankey.io/contact/) [Read the comparison](#comparison) ## Short answer Choose Entra App Proxy when Microsoft Entra is the standard identity control plane. Choose AuthBastion when the application needs a controllable authentication proxy with MFA, OIDC/OAuth2 bridging, and GovBR integration outside a Microsoft-only architecture. ## GuardianKey angle AuthBastion protects web systems from the outside in. It acts as a configurable reverse proxy, applies MFA and access policy before the application login is reached, and can bridge legacy systems to OIDC/OAuth2 identity flows without requiring source-code changes. How to frame the choice ## Different tools for *different control points.* A fair comparison starts by separating platform breadth from the specific security decision the organization needs to enforce. ### Microsoft Entra App Proxy Microsoft Entra Application Proxy publishes on-premises web applications for remote access through Microsoft Entra ID and supports Conditional Access and MFA. Entra App Proxy is powerful for Microsoft-centered remote access. AuthBastion is a focused GuardianKey layer for protecting login routes and modernizing authentication around existing web apps. ### GuardianKey AuthBastion AuthBastion protects web systems from the outside in. It acts as a configurable reverse proxy, applies MFA and access policy before the application login is reached, and can bridge legacy systems to OIDC/OAuth2 identity flows without requiring source-code changes. - Reverse proxy architecture for sensitive routes - MFA before the application login - OIDC/OAuth2 bridge for legacy systems - GovBR integration for public-sector authentication needs Comparison ## Where each option tends to fit. The best choice depends less on brand recognition and more on the control point: identity platform, fraud platform, bot platform, or a focused GuardianKey protection layer. Dimension Microsoft Entra App Proxy GuardianKey AuthBastion Primary fit Broad product capability in its category and ecosystem. Reverse-proxy mfa, oidc/oauth2 bridging, govbr integration, and modernization without application rewrites. User friction Depends on policy, challenge, step-up, or access flow design. Designed to reduce unnecessary friction while preserving security decisions. Deployment control Often strongest when adopted with the vendor's broader cloud or platform model. Designed for organizations that value on-premises, hybrid, or application-close control. Operational scope May cover more adjacent use cases beyond the narrow comparison. Focused scope with clear integration boundaries and security outcomes. GuardianKey strengths ## What to emphasize in an architecture review. 01 / Focus ### Specific control Reverse proxy architecture for sensitive routes. 02 / Experience ### Low friction MFA before the application login while keeping the user journey practical. 03 / Control ### Deployment fit Fast rollout for legacy and regulated environments, especially where sovereignty or legacy constraints matter. Balanced view ## What GuardianKey is *not trying to replace.* AuthBastion is not a complete IAM platform, SASE fabric, or global ZTNA ecosystem. It is focused on putting modern authentication controls in front of web systems that cannot be rewritten quickly. ### When Microsoft Entra App Proxy may be the better fit If the organization needs the full breadth of Microsoft Entra App Proxy's category, existing ecosystem, commercial relationships, or adjacent platform capabilities, it may be the more natural center of gravity. ### When GuardianKey AuthBastion deserves a closer look When the problem is precise, urgent, and close to the application flow, GuardianKey can be easier to evaluate through a proof-of-concept: integrate the control point, observe the decision quality, and measure user friction directly. Public references ## Product positioning reviewed. [GuardianKey AuthBastion product page](https://guardiankey.io/guardiankey-auth-bastion/) [GuardianKey AuthBastion documentation](https://guardiankey.io/docs/auth-bastion/how-it-works/) [Microsoft Entra App Proxy public product information](https://learn.microsoft.com/en-us/entra/identity/app-proxy/overview-what-is-app-proxy) ## Validate the fit in *your architecture.* Talk to GuardianKey about a focused demo, architecture review, or proof-of-concept for reverse-proxy MFA, OIDC/OAuth2 bridging, GovBR integration, and modernization without application rewrites. [Request a demo →](https://guardiankey.io/contact/) [Schedule an architecture review](https://guardiankey.io/contact/) [Plan a proof-of-concept](https://guardiankey.io/contact/)