V1 Image and Document Transformations

The following pages cover the first iteration of the Filestack REST API for image and document transformations. If you are still using this format for your transformations, we strongly encourage you to migrate to our more powerful transformation engine urls (i.e. process.filestackapi.com or process.filepicker.io) which allow for faster more complex conversions.


Examples using www.filestackapi.com/api/file/ are interchangeable with www.filepicker.io/api/file

Click here

The following conversion functions are supported by the old transformation API:

Old Transformation URL Format:

Old style conversions are executed in the following order regardless of parameter placement in the request:

resize > crop > watermark > filter > post-processing (rotate, quality, format).

To make a crop happen before a resize, use the crop_first=true parameter.

Filestack has a limit to how large the images it will accept for transformations can be.The maximum accepted image size is 100,000,000 pixels, so an image with this many pixels could have width and height combinations like 10,000 x 10,000 or 5,000 x 20,000, etc.

When using the old style transformation urls, you can store a copy of the transformation by making a POST request to the convert endpoint with your conversion parameters and your API key. The result of the transformation will be stored to your specified storage solution.:

Store a Transformation
Store Location

Where to store the file. The default is S3. Other options are 'azure','dropbox', 'rackspace' and 'gcs'. You must have configured your storage in the developer portal to enable this feature.


The path to store the file at within the specified file store. For S3, this is the key where the file will be stored at. By default, Filestack stores the file at the root at a unique id, followed by an underscore, followed by the filename, for example "3AB239102DB_myphoto.png".


The bucket or container in the specified file store where the file should end up. This is especially useful if you have different containers for testing and production and you want to use them both on the same Filestack app. If this parameter is omitted, the file is stored in the default container specified in your developer portal.

Note that this parameter does not apply to the Dropbox file store.

Public Access

Indicates that the file should be stored in a way that allows public access going directly to the underlying file store. For instance, if the file is stored on S3, this will allow the S3 url to be used directly. This has no impact on the ability of users to read from the Filestack file URL. Defaults to 'private'.


If you have security enabled, you'll need to have a valid Filestack policy and signature in order to perform the requested call. This allows you to select who can and cannot perform certain actions on your site. Read more about security and how to generate policies and signatures