Use it in

Charts in email reports.

Email clients show images from a URL, so a chart URL in your HTML shows for every recipient. The first open renders the chart; every other open comes from cache.

Start freeSee the examples
Revenue, week 39To: team@yourcompany.com

Morning. Revenue for last week is below. Saturday was the best day.

Bar chart: revenue this week, highest on Saturday at $7,400

Set it up.

  1. Write the URL

    Start from the weekly revenue example and put your own numbers in y.

  2. Fill it in when you send

    Your report job joins this week's numbers with commas and drops them into the URL.

  3. Paste it into the template

    As an img tag with width 600 and alt text that says what the chart shows.

<img src="https://c.renderchart.com/?key=rc_pub_live_7Hq2mX9pLk4vN8sT1wEa&type=bar&x=Mon,Tue,Wed,Thu,Fri,Sat,Sun&y=4200,3900,5100,4800,6200,7400,5300&title=Revenue%20this%20week%20%28%24%29&values=1&h=400"
     width="600" height="400" alt="Weekly revenue">

Worth knowing.

Size
w=600, the usual width of an email body. The default dpr=2 keeps it sharp on phones.
Link tracking
Unknown parameters are ignored, so utm_source and the like added by your email tool never break a chart or cause a new render.
Alt text
Some clients hold images until the reader allows them. Say what the chart shows: "Revenue this week, highest on Saturday at $7,400".
Cost
One render when the numbers change, however many people open the email.
Start freeRead the URL spec