HTTPS for Custom Domains

We have added HTTPS support for our CNAME records for free.

All our CNAME records now came with a free HTTPS certificate by Let’s Encrypt. These are trusted by all major browsers and allow our users to have a full encrypted site.

When using our service directly on a site you might want a CNAME record to keep everything on the same domain, but without HTTPS support from us that would be an issue, leading the browser to notify your users that some parts are not encrypted.

Now we automatically provide HTTP and HTTP for all your CNAME records that you register with us with no additional fee or limit.

Our own domain sill operates with http:// and https://.

Cloudflare Integration

Since last June we have enabled CloudFlare CDN for our API domain:

With this change we can leverage on the amazing CloudFlare network (with over 80 delivery points) and give our users best performance and security. Our API is a highly cacheable endpoint, so it makes sense to cache all our data near our final users.

How this work? CloudFlare stands between your user browser and our own servers. When a user requests an image for the first time CloudFlare passes the request to us. We then process the image and return the final image. CloudFlare will cache this image and subsequent requests won’t hit our servers (being served by CloudFlare alone). Virtually 100% of our requests are cache hits so this will bring a significative speed-up for our final users.

We are also better protected against DDoS attacks and even when our all servers are down we can operate on some level.

Note: clients using CNAME records won’t have access to this feature – they will have to enable CloudFlare CDN for their domain.

Tutorials in Kotlin programming language

If you want to use rethumb with Kotlin check these tutorials:

Paths in Sources

Our API finally allows paths in sources. As listed by our roadmap our API didn’t allow for paths in the domain or subdomain name of a source.

From now on all these are valid sources:

  • (NEW)
  • (NEW)

This could be very useful for clients with resources on shared domains like S3, where all customers might share the same domain or subdomain.

Bring your Custom Domain Name

Starting today you can use your own domain name with rethumb.

By using CNAME records it is possible to point any subdomain to our server.

  1. Choose a subdomain: something like

  2. Create a CNAME record with and within your DNS managament service.

  3. Login into our dashboard at and create a CNAME record with your subdomain name (

  4. Wait for your DNS changes to propagate and our servers to update.

After these steps you can start using rethumb with your own domain, example:

That will work in the same way as:

More information: CNAMEs – how do they work?

Cover Resize Tutorials

Check our cover resize examples. rethumb can resize an image to cover any dimensions:

Cover resize now Available

Our new operation cover is now available. This feature allows you to resize an image to any dimension: upscaling, downscaling and cropping as needed.

An example, if you have an image with dimensions 300 x 300 px you can use the following request to get a new 150 x 200 px image:

Original image

As you can see the new image itseft have no distortion in any way:

Transformed image

This feature is very similiar to CSS background cover, you can read more about it here: CSS3 background-size Property.

Check our API for more details on how to use this new transformation.

WebP Support now Available

Support for WebP images in now available. You can use rethumb to convert WebP images to other formats like JPG or PNG and vice-versa.

Convert from WebP to JPG:

Convert from JPG to WebP:

Format Conversion Tutorials

Check our format conversion examples. rethumb can convert to and from JPG, GIF, PNG, TIFF and WebP:

Format Conversion now Available

Starting today our format conversion feature is available for all our customers.

This feature allows you to convert from an image file format to another. At the moment we can convert from and to JPG, GIF, PNG, TIFF and WebP.

The following example will convert a JPG image to GIF, PNG and WebP. Note that the format feature must be used with other transformation operation like height, square or width.

Documention on this feature is online at

It is a paid feature so you’ll need to subscribe to a paid plan. Check our prices at

Any question contact us at [email protected].