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Nexus Web App

Nexus is the full-stack web application for ABI. It provides a browser-based interface for chatting with agents, browsing the knowledge graph, and managing workspaces and organizations.

Architecture​

Nexus is integrated into the ABI monorepo as of February 2026:

libs/naas-abi/naas_abi/apps/nexus/
├── apps/
│   ├── api/              # FastAPI backend (mounted on the core ABI API process)
│   └── web/              # Next.js frontend

The Nexus FastAPI API is wired into the ABI Engine as a module - it receives the engine's configured services (TripleStore, VectorStore, BusService, etc.) at startup. The Next.js frontend and its backend share the same process.

Starting Nexus​

Nexus starts automatically with the full stack:

abi stack start

The web frontend is served at http://localhost:9879 (or your configured port).

Features​

  • Agent chat: conversation interface for all loaded ABI agents, with thread history and streaming responses.
  • Knowledge graph browser: explore entities, relationships, and ontology classes.
  • Workspace management: multi-tenant workspaces with organization and membership management.
  • File browser: browse object storage and uploaded documents.
  • Search: semantic search across the knowledge graph and vector store.

Authentication​

Local development​

The local stack seeds a single admin account on first start. Default credentials:

EmailPassword
[email protected]Admin1234!

The password is read from .env at seed time via NEXUS_USER_ADMIN_EXAMPLE_COM_PASSWORD. Change it there before sharing the stack with others.

config.local.yaml controls which method is active:

nexus_config:
  auth_password_enabled: true   # password form
  # auth_password_enabled: false  # magic link form

Switch by editing the flag and restarting the backend:

docker compose restart abi

No frontend rebuild required. The login page fetches /api/auth/config at runtime.

When auth_password_enabled: false and SMTP is not configured (the default for local dev), magic links are generated but not emailed. Retrieve the latest token directly from the database:

docker compose exec postgres psql -U abi -d nexus \
  -c "SELECT token, expires_at FROM magic_link_tokens ORDER BY created_at DESC LIMIT 1;"

Then open:

http://localhost:3042/auth/magic-link?token=<token>

Tokens expire after 15 minutes.

Tenant branding​

Nexus supports per-deployment white-labeling configured in config.yaml:

modules:
  - module: "naas_abi.modules.core.nexus"
    enabled: true
    config:
      tenant:
        title: "My AI Platform"
        logo_url: "https://cdn.example.com/logo.png"
        primary_color: "#22c55e"
        favicon_url: "https://cdn.example.com/favicon.ico"

No frontend rebuild required. Branding changes take effect on config update and service restart.

See ADR: Tenant Provisioning.

Workspace routing​

After login, Nexus redirects users to their workspace using a three-tier resolution: last-visited cookie, DEFAULT_WORKSPACE env var, then a hardcoded fallback of primary.

Production deployments must set NEXUS_DEFAULT_WORKSPACE in .env to match their workspace slug, or first-visit redirects will land on a 404.

See ADR: Default workspace routing for the full decision record.