FastCAT

FastCAT is a self-hosted, browser-based CAT/TMS stack for translation teams. It combines project intake, translation memory, terminology, rules, MT/LLM provider management, a browser editor, and an app-wide assistant in one Docker deployment.

License: source-available for non-commercial use only. Commercial use requires a separate paid license. See LICENSE.

Current state

The repository is no longer a small "TM Lite" demo. The current application includes:

• Global Setup for first-run provisioning and first admin creation
• Role-based access for admin, manager, and reviewer
• Dashboard with summary metrics and the App Agent chat panel
• Projects area with a multi-step creation wizard, provisioning flow, downloads, and project detail views
• Inbox for assigned work
• Browser editor with classic and modern modes, TM/TB/MT/LLM suggestions, concordance, QA/issues, history, bulk actions, and rendered previews
• Resources area for project templates, file type configurations, JSON/extraction templates, translation engines, translation memories, termbases, rulesets, and NMT/LLM providers
• Admin pages for users, stats, language settings, departments, and App Agent configuration
• Background provisioning and pretranslation workers

The codebase and tests currently cover XLIFF/XML, HTML/XHTML/XTML, and Office document flows (.docx, .pptx, .xlsx). TMX-backed translation memory is handled through t5memory plus tm-proxy.

Architecture

FastCAT runs as a multi-service Docker stack:

Service	Purpose	Default port
web	Nginx serving the frontend and reverse proxying the APIs	9991
frontend	React 19 + Vite single-page app	built into web
cat-api	Main CAT/TMS API, project handling, editor APIs, resources, chat backend	4000
tm-proxy	Auth, user management, and TM/TMX proxy APIs	3001
llm-gateway	OpenAI-compatible provider gateway and App Agent runtime support	5005
tm-db	Postgres persistence	5433
redis	Rate limits and worker/support state	6379
minio	S3-compatible object storage for uploads and generated artifacts	9000 / 9001
t5memory	Translation memory engine	4040
tm-backup	Periodic Postgres backup container	internal

Quick start

Requirements:

• Docker with Compose support

Start the full stack:

docker compose up -d --build

Then open http://localhost:9991.

On the first run, FastCAT redirects to Global Setup. Complete that flow to create the first admin account and initialize the application.

Local development

For day-to-day development, the simplest path is to run the full Docker stack and optionally run the frontend or cat-api locally.

Frontend:

cd frontend
npm install
npm run dev

CAT API:

cd cat-api
npm install
npm run dev

The remaining services are typically left on Docker unless you are working on them directly.

Key runtime notes

• Authentication is handled by tm-proxy.
• Project, resource, and editor APIs are exposed from cat-api.
• Files and derived artifacts are stored in MinIO by default. In AWS-style deployments, the same code can point at S3 via environment variables.
• The App Agent stores chat threads, messages, and tool calls in Postgres.
• llm-gateway speaks an OpenAI-compatible API and can bridge localhost inside containers to host.docker.internal for local model endpoints.
• ./glossaries is mounted into the stack and available to cat-api at startup.
• No TMX libraries are preloaded automatically; upload them through the UI.

Testing

Service tests:

cd frontend
npm test

cd cat-api
npm test

Docker smoke checks:

node scripts/docker-smoke-check.mjs
node scripts/app-agent-project-flow-smoke.mjs

Optional UI/screenshot checks:

node scripts/capture-ui-screenshots.mjs
node scripts/capture-collection-shell-screens.mjs

The smoke scripts exercise admin, manager, and reviewer flows, project creation, termbase access rules, and guided App Agent project creation.

Selected environment variables

Variable	Purpose
JWT_SECRET	Shared JWT signing secret used by the app services
TM_DB_URL, CAT_DB_URL	Postgres connection strings
S3_BUCKET, S3_ENDPOINT_URL, S3_PUBLIC_ENDPOINT_URL, S3_ACCESS_KEY_ID, S3_SECRET_ACCESS_KEY	Object storage configuration
REDIS_URL	Redis connection string
TM_PROXY_URL	cat-api to tm-proxy base URL
LLM_GATEWAY_URL	cat-api to llm-gateway base URL
LLM_GATEWAY_LOCALHOST_BRIDGE	Localhost rewrite for container-to-host model access
APP_AGENT_INTERNAL_SECRET	Internal auth between App Agent components
CHAT_AGENT_SYSTEM_PROMPT	Server-side system prompt for the App Agent
CHAT_LLM_PROVIDER_ID	Optional fixed provider for chat
CHAT_RATE_LIMIT_PER_MINUTE	Per-user chat rate limit
CHAT_MAX_HISTORY_MESSAGES	Chat history window loaded per turn
CHAT_TRANSLATE_MAX_CHARS	Character limit for snippet translation tool calls

Repository layout

• frontend/ - React UI
• cat-api/ - main backend
• tm-proxy/ - auth and TM/TMX proxy
• llm-gateway/ - Python gateway for providers and agent runtime
• web/ - Nginx packaging for the frontend
• docs/ - design notes, acceptance notes, and screenshot helpers
• scripts/ - smoke checks and screenshot capture helpers
• example_files/ - sample input files for manual testing

License

FastCAT is source-available, not MIT-licensed.

• Non-commercial use is allowed under the terms in LICENSE.
• Commercial use is not granted by default.
• Any commercial use requires a separate written paid license from the copyright holder.