·SecureStartKit Team
Supabase OAuth, Magic Links, MFA in Next.js [2026]
Secure OAuth, magic links, and MFA in Supabase + Next.js. PKCE flow, redirect URL allowlists, AAL2 step-up, and 5 implementation failure modes.
19 articles
Secure OAuth, magic links, and MFA in Supabase + Next.js. PKCE flow, redirect URL allowlists, AAL2 step-up, and 5 implementation failure modes.
Stripe webhook signature failing in Next.js? 5 causes: parsed body, JSON re-stringify, timestamp drift, wrong secret, missing idempotency.
Pre-launch security audit for Next.js + Supabase: 12 highest-impact checks of 30, in audit order, with triage rules. Run weeks before launch.
Supabase JWT lifecycle, ES256 asymmetric signing keys, httpOnly cookie storage, and getClaims vs getUser vs getSession for Next.js apps.
Multi-tenancy and RBAC in Supabase + Next.js. Tenant scoping via JWT claims + RLS, the composite index rule, and five cross-tenant leak modes.
OWASP Top 10:2025 mapped to Next.js + Supabase failure modes plus the architectural defenses that prevent each category. With 2026 CVEs.
CSRF, XSS, and SQL injection prevention in Next.js. Three architectural defenses tied to OWASP A05:2025 and the 2026 Next.js injection CVEs.
You shipped a Lovable, Cursor, or v0 prototype. Now you need a SaaS that won't get hacked. The 4-phase migration playbook for 2026.
Seven security checks every solo dev must verify before going live: auth, RLS, Zod, webhooks, headers, secrets, error handling. The pre-launch audit.
Five architectural patterns most Next.js SaaS templates skip: backend-only access, Zod everywhere, RLS deny-all, signed webhooks, server-only imports.
AI tools like Lovable, Cursor, Bolt, and Replit ship insecure code. The 2026 breach pattern, bug categories, and the architectural fix.
The architectural pattern that prevents Supabase data leaks. Server Actions, admin client, no NEXT_PUBLIC key for queries, ever.
Next.js 16's 'use cache' is easy to misuse. Cache the wrong thing and User A sees User B's data. The three directives explained safely.
A production security checklist for Next.js apps. Covers HTTP headers, CSP, environment variables, Server Actions, RLS, webhook verification, and more.
Claude Code CVEs, Google's $82K API key incident, 5,000+ repos leaking ChatGPT keys. Learn how AI tools expose your secrets and how to lock them down in Next.js.
Vibe coding tools like Cursor and v0 build apps fast, but they often ship vulnerabilities. Here is the technical audit checklist for Next.js and Supabase apps.
Server Actions are public HTTP endpoints. Validate every payload with Zod before any database call. Patterns for Next.js 16 and Zod 4 with CVE context.
The Lovable hack exposed 170+ apps through missing RLS. Here's what went wrong and the exact steps to secure your Supabase database.
Most SaaS templates expose your database to the browser. Here's why that's dangerous and how SecureStartKit does it differently.