How I Built a Discord Activity Heatmap Bot with Python and discord.py

#python #discord #showdev #programming

I've been running a Discord server for a while and always wondered: "when is my community actually online?"

Discord doesn't show you this. You can see who's online right now, but there's no way to see patterns over time, no weekly view, no hourly breakdown, nothing.

So I built Heatmap Bot.

What it does

Heatmap Bot tracks your server's activity and turns it into a heatmap, a 7×24 grid showing activity by day and hour for the past week. It also supports:

Daily bar chart view
Monthly trend chart
Channel breakdown
Member leaderboard
Week-over-week comparison
Weekly auto-reports
Peak activity alerts
CSV data export

Tech stack

Python 3.13 with discord.py 2.x
SQLite with aiosqlite for async DB access
matplotlib + numpy for heatmap rendering
aiohttp for the webhook server
Railway for hosting
Ko-fi for payments (manual grant flow)

The interesting part, rendering heatmaps

The heatmap is a 7×24 numpy array. Each cell is the count of events at that day/hour combination, converted from UTC to the server's local timezone.

pythondef aggregate_to_heatmap_grid(events, timezone, days):
    grid = np.zeros((7, 24), dtype=float)
    tz = pytz.timezone(timezone)
    for event in events:
        ts = event.get("timestamp", 0)
        dt = datetime.fromtimestamp(ts, tz=tz)
        grid[dt.weekday()][dt.hour] += 1
    return grid

The rendering uses matplotlib with a custom blurple→pink gradient to match Discord's aesthetic.

The hard part - Railway + Discord rate limits

The trickiest issue was Discord's Cloudflare rate limiting. Too many reconnects from the same IP gets you a 1015 error, temporarily banned. The fix was switching Railway regions to get a new IP.

If you're deploying a Discord bot, make sure your restart policy doesn't cause rapid reconnect loops.