May 26, 2011 · Updated Sep 13, 2026

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# Introducing /s3/store Robot's 'url\_prefix' parameter

![Felix Geisendörfer](/assets/images/teammates/avatar-felixge-1.jpg)

**Felix Geisendörfer**

Co-founder · Berlin, Germany · Show bio

[](https://x.com/felixge)[](https://github.com/felixge)

We have some good news for people using CDNs or bucket names that are not well-formed. As of today, we are supporting a new parameter called `url_prefix` for our [/s3/store](/docs/robots/s3-store.md) Robot.

Before, we would always return URLs prefixed with `"https://<bucket>.s3.amazonaws.com/"`, where `<bucket>` is the name of the S3 bucket in which we stored the file.

This new option now allows you to define any prefix, for example `"https://cdn.example.com/"`, in case that is the name of your CDN domain.

Enjoy!

[#file-exporting-service](/blog/tags/file-exporting-service.md)[#s3-store-robot](/blog/tags/s3-store-robot.md)

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