Platform architecture

This section describes how Casa Conect is put together, component by component. It is written for the people who assess software before an office adopts it, and for anyone curious about what happens behind the interface. For the security posture specifically, start with the Security overview.

The shape of the system

Casa Conect is a single codebase, a monorepo, containing a small number of deployable applications and a larger set of internal libraries that they share. Everything is written in TypeScript in strict mode, and every piece of external data is validated against a schema at the boundary.

Browser · Microsoft Word · Email · Share-link recipients
        │
        ▼
   Edge: CDN + web application firewall
        │
  ┌─────┴──────────────┬──────────────────┬─────────────────┐
  ▼                    ▼                  ▼                 ▼
Dashboard            API               Collaboration     Word add-in
(web app)      (REST + typed RPC)      server (live      (static app)
                       │               editing)
        ┌──────────────┼───────────────────────┐
        ▼              ▼                       ▼
   Background       Rendering             Data layer
   jobs             service               PostgreSQL · object storage · cache
   (agent sessions, (Word → PDF)
   indexing, sync)

Applications

Application	Role
Dashboard	The signed-in web application, and the public pages behind share links
API	The single backend. Every client talks to it. All authorization happens here.
Collaboration server	Holds the live state of documents that are being edited, and synchronizes editors in real time
Rendering service	Converts Word documents to PDF. Internal only, with no public surface.
Background jobs	Durable and scheduled work: agent sessions, document indexing, drive sync, workflows, reminders
Word add-in	The task pane inside Microsoft Word
Website	The public marketing site. It has no connection to customer data.

Libraries

Each library has one responsibility and a narrow public surface.

Library	Responsibility	Read more
Agent	The AI agent: models, tools, memory, workflows, containment	Agent runtime
Jobs	Every background and scheduled task	Background jobs
Editor	The document model, tracked changes, page layout	Editor and collaboration
OOXML engine	Reading, validating, editing and writing Word files	Document engine
DOCX bridge	The one place where the editor’s model and Word’s format meet	Document engine
RAG	Parse, chunk, embed, index, search, rerank	Search pipeline
Storage	The only gateway to object storage, including malware-scan verdicts	Storage and encryption
Share links	The cryptography and rules behind account-free sharing	Storage and encryption
Email and Operations	Templates, the send path, and inbound mail processing	Email pipeline
DMS	Adapters for Google Drive, OneDrive and SharePoint	Integrations layer
Billing	Subscriptions, entitlement, metering and spending guards	Billing engine
Database	Schema, migrations and typed queries	Storage and encryption
Cache	Every use of the in-memory store, one module per purpose	Storage and encryption
Logger, Health, Analytics	Structured logs, dependency probes, privacy-scrubbed analytics	Observability
UI and Utils	The design system, shared constants and pure helpers

Design principles

Authorization lives in one place

Access control is enforced in the API and the query layer, keyed to an identity that is verified cryptographically on every request. Routers orchestrate. Business rules live in an application layer beneath them. The database reinforces tenancy with composite foreign keys. See Access control.

Narrow surfaces

Libraries expose small, specific entry points rather than general-purpose clients. The cache is not a generic key-value client, but some thirty modules, each owning one concern. Storage is a single gateway. There is exactly one code path that writes to a Word document from the add-in.

One implementation for each concern

Every route by which a document arrives passes through the same indexing function. Every version, from any surface, lands in one history. There is one agent for every situation, configured per request, rather than a family of agents that could drift apart.

Fail closed where it matters, fail open where it is safe

Security decisions fail closed: an incomplete malware scan, a failed safety review, a limiter that is down during PIN entry. Protective conveniences fail open, with a log entry: a general rate limiter backed by the edge firewall, or a cache read.

Honest degradation

When something cannot be done exactly, the user is told. A font that cannot be matched is named. A Word construction that cannot be represented produces a notice. A document that is not yet indexed is reported as such.

Bounded work

Every unit of background work has a time limit, a retry policy and a concurrency cap. Agent turns have step budgets. Queues apply backpressure before anything falls over.

Infrastructure as code

The cloud environment is defined in Terraform, with state and runs managed remotely and cloud access through short-lived federated credentials. There are no static keys. Production changes are applied manually after review. Database migrations are applied by the deployment pipeline, never from a developer’s machine.

Technology at a glance

Layer	Technology
Language and runtime	TypeScript, Bun, Node.js
Web application	Next.js, React
API	Hono, tRPC, Zod, OpenAPI
Agent	Mastra, the Vercel AI SDK
Background work	Trigger.dev
Editor	TipTap and ProseMirror, Yjs, Hocuspocus
Documents	An in-house OOXML engine. LibreOffice, through Gotenberg, for PDF.
Data	PostgreSQL (Amazon Aurora) with pgvector, Drizzle ORM, Valkey
Identity	WorkOS AuthKit
Cloud	AWS, Frankfurt, managed with Terraform

Data flows

Four journeys through the system, end to end.

Security overview

The same system, from a security point of view.

Architecture

Components

The shape of the system

Applications

Libraries

Design principles

Technology at a glance

Next

Data flows

Security overview

​The shape of the system

​Applications

​Libraries

​Design principles

​Technology at a glance

​Next

Data flows

Security overview

The shape of the system

Applications

Libraries

Design principles

Technology at a glance

Next