HTML to image API — render your HTML and CSS as images or PDFs
Paste your own HTML and CSS into an HTML template, mark the parts that change with double-brace placeholders, and render it to PNG, JPEG, WebP or PDF with one API call — drawn by headless Chromium, so modern CSS renders as it does in Chrome.
100 renders / month free · no card · paid plans are never blockedTry it free: convert HTML to a PNG in your browser →How it works
Paste your HTML
Create an HTML template in the editor and paste in your markup and styles. A live preview shows exactly what will render.
Mark the variables
Wrap anything that changes in double braces — a title, a price, an image URL. The template’s defaults fill in whatever a request leaves out.
Render via API
POST the template id with your values as modifications and get back an image or PDF URL — or put the values in a signed URL for og:image tags and email.
One API call
curl https://api.mostlyrender.com/v1/renders \
-H "Authorization: Bearer mr_test_YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{"templateId":"tpl_html_card","modifications":{"title":"Northwind Co.","subtitle":"v2.4 · 14 Oct"}}'Questions
Can I use my own HTML instead of the visual editor?
Yes. An HTML template keeps your markup and CSS exactly as written, and any double-brace placeholder becomes an API parameter. HTML templates and visual layer templates render through the same API, so you can use both in one account.
Can I send raw HTML in each API request?
Not directly. The HTML lives in a saved template and each request sends only the values, which keeps requests small and lets identical renders be served from cache. To capture a page that is already online, send its URL to the screenshot endpoint instead.
Does CSS render the way it does in my browser?
Templates are rendered by headless Chromium, so modern CSS — flexbox, grid, custom properties — behaves as it does in Chrome.
Are my values escaped when they fill a placeholder?
Yes. A double-brace placeholder inserts the value as text with HTML characters escaped, so user data cannot inject markup. Use a triple-brace placeholder only when you deliberately want to insert trusted HTML.
Which output formats are supported?
PNG (the default), JPEG, WebP and PDF from the same template. Signed render URLs also accept q (0–100) for JPEG and WebP quality and scale (1–3) for sharper output on high-density screens.
How is it different from HTMLCSStoImage?
Both turn HTML and CSS into images. MostlyRender adds a visual layer editor alongside HTML templates and bills overage at $3–$5 per 1,000 against HCTI’s $10 in our June 2026 review. HCTI is the cheaper way in, at $14 for 1,000 images.
How much does HTML to image rendering cost?
Each image or PDF is one render. The Free plan includes 100 renders a month; Starter is $19 for 2,000, Pro $49 for 10,000 and Scale $149 for 50,000, with published overage instead of a hard cap on paid plans.