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Code challenges

Want to test your skills with VCL or the Compute platform? Our code challenges each present a problem and invite you to write edge code to solve it. We use Fastly Fiddle to run the code, and test that it produces the outcome we want.

Getting started

To take a challenge, you need to be logged into a manage.fastly.com account. The number of points available for each challenge is proportional to the difficulty, and doesn't necessarily reflect the amount of code you need to write.

All the challenges are solvable using knowledge available in this Developer Hub; so check out the learning resources and reference docs. Sometimes you might even find ready-made answers in our code examples library. Some challenges will offer links to relevant docs in the definition of the objective, or in hints next to the code editor.

HINT: There's no penalty to running the code even if you know it won't pass yet. Feel free to hit the RUN button right away, before you even do anything, to see what tests fail!

Code challenges are new, and we appreciate your feedback! Let us know what you think using the comment button at the bottom of any page.

Available challenges

Pick a challenge from the selection below, and write code to make the tests pass.

Enabling Image optimization
Fastly's image optimizer won't touch requests until you turn it on
Enrich requests with geolocation
Add location data to requests before they are passed to the backend
Hit-for-pass on 403s
Why doesn't passing an error response from origin create a hit-for-pass object?
Distinguish origin from Fastly errors
Fastly generates error responses in some cases, but origin servers can also return error responses. Can you tell the difference?
Robots.txt at the edge
Generate pre-determined content at the edge without making requests to a backend
Modify a JSON response
Parse and modify response bodies at the edge
Normalizing the Accept header
Content negotiation can reduce cache efficiency. Fix this by reducing the number of variations of the Accept header.
Retaining a HEAD request
Ensure that HEAD requests from clients are forwarded to origin as HEAD
Synthetic status page
Composing content directly at the edge is a great way to provide a status page with minimal dependencies
Backend token authentication
Add an authentication token to a client request to authenticate with the backend
Synthetic error response
Pass on key information from a backend error in an edge-generated error page
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