--- title: The 403 That Redesigned Our Auth: Three Login Systems,... description: A retrospective on how a multi-tenant MICE SaaS platform accumulated three separate authentication systems organically, and how a 403 error triggered by a... canonical: https://daily.dev/posts/the-403-that-redesigned-our-auth-three-login-systems-one-rust-middleware-qzxvrcfdm twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: The 403 That Redesigned Our Auth: Three Login Systems, One Rust Middleware | daily.dev og:description: A retrospective on how a multi-tenant MICE SaaS platform accumulated three separate authentication systems organically, and how a 403 error triggered by a... og:url: https://daily.dev/posts/the-403-that-redesigned-our-auth-three-login-systems-one-rust-middleware-qzxvrcfdm og:image: https://api.daily.dev/og/posts/QzxvrcFdM.png og:image:alt: The 403 That Redesigned Our Auth: Three Login Systems, One Rust Middleware og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # The 403 That Redesigned Our Auth: Three Login Systems, One Rust Middleware **[Medium](https://daily.dev/sources/medium_js)** · 13 min read · 0 upvotes · 0 comments ## Summary A retrospective on how a multi-tenant MICE SaaS platform accumulated three separate authentication systems organically, and how a 403 error triggered by a cross-event token mismatch led to unifying all three under a single Rust middleware. The post explains the domain reasons each auth system existed (Supabase Auth for platform staff, custom bcrypt JWT for exhibitors scoped to event+year, a third for business matchmaking), why merging the user tables wasn't the right fix, and how a fallback chain middleware handles all three token dialects. Honest trade-offs are covered: three secrets means three of everything to rotate, the service-role swap for addon identities removes database-enforced tenancy as a safety net, 24-hour stateless JWTs are too long for the trust model, and the legacy default cookie lingered. The key insight: cryptographic authenticity is easy; token relevance (is this the right credential for this context?) needs a single owner. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: --- Tags: [#authentication](https://daily.dev/tags/authentication), [#rust](https://daily.dev/tags/rust), [#jwt](https://daily.dev/tags/jwt), [#multi-tenancy](https://daily.dev/tags/multi-tenancy) [View this post on daily.dev](https://daily.dev/posts/the-403-that-redesigned-our-auth-three-login-systems-one-rust-middleware-qzxvrcfdm) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"The 403 That Redesigned Our Auth: Three Login Systems, One Rust Middleware","url":"https://daily.dev/posts/the-403-that-redesigned-our-auth-three-login-systems-one-rust-middleware-qzxvrcfdm","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/the-403-that-redesigned-our-auth-three-login-systems-one-rust-middleware-qzxvrcfdm"},"datePublished":"2026-07-25T19:30:05.624Z","dateModified":"2026-07-25T19:30:47.316Z","description":"A retrospective on how a multi-tenant MICE SaaS platform accumulated three separate authentication systems organically, and how a 403 error triggered by a...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b76159d8c6929cc6f9edb114eb256f61?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b76159d8c6929cc6f9edb114eb256f61?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Medium","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Medium","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/medium","url":"https://daily.dev/sources/medium_js"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/the-403-that-redesigned-our-auth-three-login-systems-one-rust-middleware-qzxvrcfdm","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"authentication,rust,jwt,multi-tenancy","timeRequired":"PT13M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Medium","item":"https://daily.dev/sources/medium_js"},{"@type":"ListItem","position":3,"name":"The 403 That Redesigned Our Auth: Three Login Systems, One Rust Middleware"}]} ```