Cloudflare Error 1035: Invalid Request Rewrite: Invalid URI Path
Error 1035 occurs when a Cloudflare Transform Rule (URL rewrite) generates an invalid URI path. Transform Rules let you modify request URLs, headers, and other properties at the Cloudflare edge before the request reaches your origin. If a dynamic rewrite expression produces a path that is not a valid URI — for example, containing illegal characters, missing the leading slash, or resulting in an empty path — Cloudflare returns 1035 instead of forwarding the malformed request.
Status
Error 1035: Invalid Request Rewrite: Invalid URI PathExample
GET /category/sale%20items HTTP/1.1
Host: www.example.com
User-Agent: Mozilla/5.0
Accept: text/htmlHTTP/1.1 409 Conflict
Server: cloudflare
CF-RAY: 7e5f6a7b8c9d0124-SOF
Content-Type: text/html
<!doctype html>
<html>
<head>
<title>www.example.com | Error 1035</title>
</head>
<body>
<h1>Error 1035: Invalid request rewrite: invalid URI path</h1>
<p>A Cloudflare Transform Rule on this site produced an invalid URI path. Please contact the site owner.</p>
</body>
</html>How to Troubleshoot
Review your Transform Rules
In the Cloudflare dashboard, go to Rules > Transform Rules. Check the URL rewrite rules and verify their expressions produce valid paths for all possible request inputs.
Test with specific request paths
Identify which URL triggers the error and trace it through your rewrite rules to see what output the expression generates.
Add validation to expressions
Use conditional expressions in your rewrite rules to handle edge cases where the rewrite might produce an invalid path. Add a default fallback path.
Common Causes
Rewrite expression produces an invalid path
highThe Transform Rule's expression evaluates to a string that is not a valid URI path — it may contain spaces, special characters, or be empty.
Dynamic expression references an undefined field
mediumThe rewrite rule uses a variable or field that does not exist for the current request, resulting in an unexpected or empty value.
Regex replacement error
mediumA regex-based rewrite produces malformed output due to incorrect capture group references or pattern matching.
Related Error Codes
Invalid Request Rewrite: Maximum Length Exceeded
A Cloudflare Transform Rule produced a URL that exceeds the maximum allowed length.
Invalid Rewrite Rule: Failed to Evaluate Expression
A Cloudflare Transform Rule's expression could not be evaluated at runtime.
Invalid Request Rewrite: Header Modification Not Allowed
A Transform Rule attempted to modify a request header that Cloudflare does not allow to be changed.
Frequently Asked Questions
This reference was compiled from official RFCs, protocol specifications, and hands-on troubleshooting experience. AI tools were used primarily for formatting and organizing the content on the page.