# Clerk vs FusionAuth: which do AI models recommend for CIAM, October 2026

IT AI Recommendation Index, October 2026 Edition, Customer identity and access management. Three of fourteen models named Clerk first on the direct prompt; zero named FusionAuth. Page: https://it-ai-index.com/identity/customer-identity-and-access-management/clerk-vs-fusionauth/

| | First-choice share | Rank | Negative rate | Labels | Models naming it |
|---|---|---|---|---|---|
| Clerk | 18% | #3 of 14 | 3% | 31 | 12 of 14 |
| FusionAuth | 5% | #6 of 14 | 5% | 22 | 11 of 14 |

## The direct prompt, model by model

- Qwen 3.7 Flash: clerk first (first choices: Auth0, Clerk) (alternatives: Microsoft Entra ID)
- Kimi K2: clerk first (first choices: Clerk, Frontegg) (alternatives: FusionAuth, WorkOS)
- MiniMax M2.5: clerk first (first choices: Auth0, Clerk) (alternatives: Descope, LoginRadius)
- GPT-5.4 mini: neither first, one named (first choices: Frontegg) (alternatives: Auth0/Okta Customer Identity Cloud, FusionAuth, Okta)
- Gemini 3.5 Flash: neither first, one named (first choices: WorkOS) (alternatives: Clerk, Frontegg, Kinde)
- Perplexity Sonar: neither first, one named (first choices: LoginRadius) (alternatives: Clerk, Frontegg, Microsoft Entra External ID)
- Grok 4.1 Fast: neither first, one named (first choices: Auth0) (alternatives: Clerk, Frontegg, FusionAuth, Microsoft Entra External ID, Stytch, WorkOS)
- DeepSeek V4 Flash: neither first, one named (first choices: Auth0, Frontegg) (alternatives: Clerk, Microsoft Entra External ID, Stytch)
- Llama 4 Maverick: neither first, one named (first choices: LoginRadius) (alternatives: Clerk, OneWelcome Identity Platform)
- GLM 4.7 FlashX: neither first, one named (first choices: Auth0) (alternatives: Clerk, Descope, LoginRadius, Microsoft Entra External ID)
- Claude Haiku 4.5: neither named (first choices: Descope, Frontegg) (alternatives: OneWelcome Identity Platform, SSOJet, WorkOS)
- Mistral Small: neither named (first choices: LoginRadius) (alternatives: Thales OneWelcome)
- GPT-6 Luna: neither named (first choices: WorkOS AuthKit) (alternatives: Auth0, Microsoft Entra External ID, Stytch)
- Muse Glimmer 30B: neither named (first choices: Frontegg, LoginRadius) (alternatives: Auth0, Ping Identity)

## What the models said about Clerk

- "Choose Clerk only if you are a startup ... not necessarily the cheapest long-term option" (Perplexity Sonar, budget prompt, soft negative)
- "For most companies with limited budgets, Clerk's free tier or self-hosted Keycloak are the two best choices" (DeepSeek V4 Flash, budget prompt, first choice)
- "Clerk is my pick for a small team that wants to keep costs low without building much authentication infrastructure." (GPT-6 Luna, budget prompt, first choice)
- "Frontegg and Clerk are particularly well-suited due to their B2B-focused features and ease of integration" (Mistral Small, paraphrase prompt, first choice)

## What the models said about FusionAuth

- "Lower ongoing costs but requires more ops" (Kimi K2, scale prompt, soft negative)
- "Prioritize platforms with strong mid-market fit like LoginRadius (simplicity) or FusionAuth (cost-effective self-hosting)." (Grok 4.1 Fast, scale prompt, first choice)
- "Lowest total cost (no per‑MAU fees): Keycloak or FusionAuth (self‑hosted)." (GLM 4.7 FlashX, budget prompt, first choice)
- "Best overall for tight budgets: FusionAuth" (GPT-5.4 mini, budget prompt, first choice)

Share is the count of first choices across the direct, paraphrase, budget and scale prompts over all fourteen models, for a mid-market B2B company; rank is within the category. Comparisons are drawn for the top eight products in each category. Published under CC BY 4.0; the output is the models' output, and nothing here is a recommendation by the index.