Supabase Dashboard Builder

Build rich admin dashboards using Supabase PostgREST API + vanilla JS + D3/Chart.js. No build step, no framework — just HTML files served by FastAPI StaticFiles.

Architecture

FastAPI Server
├── api.py (thin proxy to Supabase REST)
├── static/
│   ├── shell.js + shell.css (shared theme)
│   ├── dashboard/
│   │   ├── index.html (main page)
│   │   ├── agents.html
│   │   ├── skills.html
│   │   └── ...

Step 1: API Layer

Create a thin FastAPI proxy that wraps Supabase REST calls. This keeps the Supabase key server-side.

import httpx
from fastapi import FastAPI

SUPABASE_URL = os.environ["SUPABASE_URL"]
SUPABASE_KEY = os.environ["SUPABASE_SERVICE_KEY"]
HEADERS = {"apikey": SUPABASE_KEY, "Authorization": f"Bearer {SUPABASE_KEY}"}

app = FastAPI()

@app.get("/api/mc/{table}")
async def get_table(table: str, select: str = "*", limit: int = 100, offset: int = 0):
    allowed = {"ai_agents", "skills", "knowledge_vault", "tools", "workflows"}
    if table not in allowed:
        raise HTTPException(403, "Table not allowed")
    url = f"{SUPABASE_URL}/rest/v1/{table}?select={select}&limit={limit}&offset={offset}"
    async with httpx.AsyncClient() as client:
        r = await client.get(url, headers={**HEADERS, "Prefer": "count=exact"})
    return r.json()

Key pattern: Lightweight selects

Tables with large text columns (system_prompt, embeddings) will timeout if you SELECT *. Always specify columns:

?select=id,name,type,status,created_at

Add select parameter to every API endpoint and default to lightweight fields.

Step 2: Shared Shell

Create shell.js and shell.css that every page imports:

// shell.js
function createShell(pageTitle, navItems) {
    // Returns: sidebar (collapsible) + top bar + main content area
    // navItems: [{label, href, icon, active}]
}

function createCard(title, content, footer) {
    // Dark-themed card with header, body, optional footer
}

function createTable(headers, rows, options) {
    // Sortable, searchable table with pagination
}

function mcFetch(endpoint, params = {}) {
    // Wrapper: fetch(`/api/mc/${endpoint}?${new URLSearchParams(params)}`)
    // Handles errors, loading states
}

function createSearchBar(placeholder, onSearch) {
    // Debounced search input
}

CSS variables for consistent theming:

:root {
    --bg-primary: #0a0a0f;
    --bg-card: #12121a;
    --bg-hover: #1a1a2e;
    --text-primary: #e0e0e0;
    --text-secondary: #888;
    --accent: #6c63ff;
    --accent-glow: rgba(108, 99, 255, 0.3);
    --border: #2a2a3e;
    --success: #4caf50;
    --warning: #ff9800;
    --danger: #f44336;
}

Step 3: Page Patterns

Data Grid Page (Agents, Skills, Tools)

┌─────────────────────────────┐
│ Search bar + Filter chips    │
├─────────────────────────────┤
│ Stats row (total, active,    │
│ by type)                     │
├─────────────────────────────┤
│ Sortable table or card grid  │
│ with pagination              │
└─────────────────────────────┘

Force Graph Page (System Overview)

Use D3.js force-directed graph:

• Nodes = entities (agents, tools, skills)
• Edges = relationships (agent uses tool, skill teaches concept)
• Color by category, size by importance
• Click node → side panel with details
• Zoom + pan + drag

Chart Page (Analytics, Metrics)

Use Chart.js:

• Radar charts for multi-dimensional scores
• Line charts for time series
• Bar charts for comparisons
• Doughnut for category breakdown

Step 4: FastAPI Static Mount

from fastapi.staticfiles import StaticFiles

# Mount AFTER API routes
app.mount("/static/mc", StaticFiles(directory="static/mc"), name="mc-static")

# Convenience page routes
@app.get("/mc/{page}")
async def serve_mc_page(page: str):
    return FileResponse(f"static/mc/{page}")

@app.get("/mc/")
async def serve_mc_index():
    return FileResponse("static/mc/index.html")

Common Bugs & Fixes

1. Double-prefix in mcFetch: Agents write mcFetch('/api/mc/agents') when mcFetch already prepends /api/mc/. Fix: mcFetch('agents') or make mcFetch accept both.

2. CORS issues in dev: Add CORS middleware if frontend is on different port:

   app.add_middleware(CORSMiddleware, allow_origins=["*"], allow_methods=["*"], allow_headers=["*"])
   

3. Supabase timeout on large tables: Use select parameter + limit + offset. Never SELECT * on tables with 1000+ rows or text columns > 1KB.

4. Chart.js canvas reuse: Destroy previous chart instance before creating new one on the same canvas, or charts stack invisibly.

Deployment

Works on any platform that serves Python (Railway, Fly, Render):

• Static files are served by FastAPI — no separate CDN needed
• Supabase key stays server-side in env vars
• No build step — edit HTML, refresh browser