Comma

Share a Plotly chart as a link

Plotly's whole value proposition is that the chart is interactive: hover for the value, drag to zoom, click the legend to isolate a series. Then you share it, and the interaction is the first thing to die. It becomes a PNG in Slack, where nobody can check the number under the peak.

The self-contained HTML file that write_html produces already solves the technical half. What it does not solve is that the file lives on your disk.

Publish it

import plotly.express as px, requests, os

fig = px.line(df, x="day", y="signups", color="channel")
fig.write_html(
    "chart.html",
    include_plotlyjs="https://cdn.jsdelivr.net/npm/plotly.js-dist-min@2/plotly.min.js",
)

requests.post(
    "https://commareports.com/api/v1/reports",
    headers={"Authorization": f"Bearer {os.environ['COMMA_API_TOKEN']}"},
    json={"title": "Signups by channel", "html": open("chart.html").read()},
).raise_for_status()

Two ways to handle the library, both fine:

  • Inline (include_plotlyjs=True) — one truly self-contained file, about 3.5 MB of plotly.js, still under the 5 MB HTML cap on its own but tight if you have a lot of data points.
  • CDN — use jsdelivr, unpkg, cdnjs or esm.sh as above. Plotly's default "cdn" value points at an origin Comma's CSP does not allow, so pass the full jsdelivr URL instead and the chart loads in a few KB of HTML.

Make it a report, not a chart

A lone figure rarely answers a question. Compose the document instead:

parts = [fig.to_html(full_html=False, include_plotlyjs=False) for fig in figs]
html = f"""<!doctype html><meta charset="utf-8">
<script src="https://cdn.jsdelivr.net/npm/plotly.js-dist-min@2/plotly.min.js"></script>
<h1>Weekly growth</h1>
<p>Paid signups fell 12% after the pricing change; organic is flat.</p>
{"".join(parts)}"""

Now there is prose to anchor comments to, which is what turns a chart into a decision. See commenting on HTML.

Limits

  • HTML body: 5 MB. Big traces add up fast — downsample, or split into several reports.
  • Scripts run, sandboxed: allow-scripts, no allow-same-origin. Script and style CDNs are limited to jsdelivr, unpkg, cdnjs and esm.sh.
  • 60 requests/minute per token.

Try it

Comma is free — unlimited reports, unlimited commenters, unlimited revision history.

Publish a chart →

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