| Disclaimer up front; party in back: I'm about to discuss a freemium service that I built & operate related to this :) I looked around for a solution like this for a while last year while building a new weekly email for Ramen[1]. I tried a bunch of services but ran up against a bunch of issues mentioned in this thread: - GET query string character limit - Stress around unreliability of free alternatives - Need to be able to handle large spikes of image generation when sending emails So I ended up building a service and turning it into a freemium product: ChartURL.com[2] It is: - Free for low usage w/ branding - Based on C3.js[3] (for major flexibility) - Supports datamaps.github.io[4] - Has an API whereby you can POST huge datasets and get back a short URL that can be used in an img tag - Supports retina & `srcset` via a `retina=1` option You need to sign the URLs which means it's not a simple "just drop the data in the URL" but it's close. I'll hang out in the comments here for a while if any of you want to ask questions about it. [1] https://ramen.is [2] https://charturl.com [3] http://c3js.org/reference.html [4] http://datamaps.github.io |