ContentTab – Headless CMS Platform with AI Pipeline
ContentTab is a headless CMS platform delivered as a monorepo of three independent applications: a NestJS 10 modular monolith backend, a Next.js 14 App Router admin dashboard, and a Next.js 15 marketing site.
The Challenge
Organizations managing multilingual content at scale face a convergence of hard problems: rigid CMS schemas that resist extension, fragmented authorization models across teams, unreliable AI integrations that silently fail mid-stream, and zero visibility into API consumption. Existing solutions force a tradeoff between rigid monolithic tools or disjointed glue code.
Our Solution
We architected and built ContentTab — a NestJS 10 modular monolith backend exposing 20+ feature modules across 30+ route prefixes backed by MongoDB (24 Mongoose schemas). It features dual-authentication (JWT + API key/secrets), workspace-scoped embedded RBAC, and a provider-agnostic AI streaming pipeline with atomic credit reservations.
Key Features Delivered
AI Content Pipeline with Multi-Provider Failover
Provider-agnostic AI layer (HuggingFace Inference) supporting 5 operations with real-time SSE streaming, 4 fallback LLM parsers, and atomic credit reservation using MongoDB $inc.
Workspace-Scoped ACL with Embedded RBAC
Roles and members are embedded directly in Workspace documents to eliminate N+1 queries. Hierarchical permissions (delete → write → read) across 13 resources.
Floating AI Widget with CSS Custom Highlight API
Glass-morphism floating AI prompt box over EditorJS with selection persistence (CSS Custom Highlight API + DOM injection) for cross-block replacements.
Headless Custom Schema Engine & Content Versioning
Extensible custom fields (`cs[]` array) without database migrations, coupled with full audit-safe content versioning, split-pane diff comparisons, and backup restores.
Dual-Authentication & Programmatic REST API
Dual auth (JWT + API key/secret pairs) with Redis sliding-window rate limiting, full request logging, and observable programmatic API access.
Multi-Tenant Workspace & Invitation Engine
Isolated workspaces with invitation lifecycle management, seeded system roles, and full frontend ACL mirroring (<Can> component, usePermission hook).
The Impact
ContentTab provided enterprise teams with schema-agnostic content management and fail-safe streaming AI generation.
- Prevented customer billing data loss via atomic credit reservations and automatic failure refunds
- Eliminated developer dependency for new content models through dynamic custom field schemas
- Accelerated team onboarding with workspace-embedded RBAC and instant permission assignment
- Ensured zero-downtime AI streaming via automated primary/fallback provider failover
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