Charts for newsletters
Newsletter platforms differ - some want Markdown, some rich HTML - but almost all accept remote images. ChartKit gives you one stable URL per issue graphic.
Platform patterns
Ghost and many MD-first tools accept `!alt`. Buttondown/Medium-like editors often need the raw `<img>` from the ChartKit copy field.
Substack’s editor varies - test both Markdown image syntax and the image insert dialog with your URL.
Use cases
- Creator economy weekly digests with a single “chart of the week”.
- Company internal Substack-style updates with KPI sparklines rendered as PNG.
- Paid tiers that get the same chart URL gated by the newsletter platform, not ChartKit.
Examples
PNG suitable for narrow newsletter columns
https://getchartkit.com/api/chart?type=line&labels=Issue+20,Issue+21,Issue+22,Issue+23&s0=4200,4450,4680,4910&s0name=Opens&title=Open+rate+trend&format=png&w=580&h=320&valueFormat=compactHTML `<img>` (many ESPs)
<img src="https://getchartkit.com/api/chart?type=line&labels=Issue+20,Issue+21,Issue+22,Issue+23&s0=4200,4450,4680,4910&s0name=Opens&title=Open+rate+trend&format=png&w=580&h=320&valueFormat=compact" alt="Monthly revenue" width="600" height="360" />Markdown (for MD→HTML pipelines)
Donut “share of voice” graphic
https://getchartkit.com/api/chart?type=donut&labels=Essay,Podcast,Video&s0=55,30,15&s0name=Mix&title=Content+mix&format=png&w=480&h=420Horizontal bar for sponsor rankings
https://getchartkit.com/api/chart?type=horizontal-bar&labels=Sponsor+A,B,C,D&s0=12,9,7,5&s0name=Clicks&format=png&w=560&h=340Build the chart for this issue
Adjust fields and copy URL, HTML, Markdown, or an AI prompt. See the [URL parameters](/docs/url-parameters) reference if you are editing links by hand.
Preview
Copy
Show snippets
How it works
- Draft issue text, freeze numbers, build the chart, copy Markdown or HTML.
- Paste early - some editors strip hotlinked images and require upload; download PNG from the URL if needed.
- Archive issues should keep working: avoid expiring intermediaries when possible.
Use with ChatGPT or Claude
LLM-written issues should reference ChartKit URLs explicitly so text and graphics stay in sync.
Compare with charts for email for ESP-specific HTML notes.
FAQ
- Markdown or HTML?
Try Markdown in MD-native tools; fall back to `<img>` when previews break.
- SVG allowed?
Prefer PNG for widest newsletter compatibility.
- Free?
ChartKit public chart URLs are meant for normal trial throughput.
- Can I use Google Sheets data?
- JavaScript?
Not required for readers.