💡Feature Request: Support for custom request headers

[Mercuria1x]

Describe the feature you'd like

Currently, cloudflared only allows setting the Host header ,but there's no way to add or modify other headers.

I would like cloudflared to support adding custom and overwriting HTTP request headers when forwarding traffic through a tunnel.

Describe alternatives you've considered
run an additional reverse proxy (like Nginx or Traefik) solely to manipulate headers

Additional context
By supporting this directly in cloudflared, users wouldn't need to run an additional reverse proxy (like Nginx or Traefik) solely to manipulate headers. This would simplify deployment and reduce resource consumption, especially in resource-constrained environments.

[absar0920]

added a pr for this feature.

[nikitacano]

Our recommended and most powerful way to handle this today is at the Cloudflare edge, using features like Transform Rules or, for more complex logic, Snippets and Workers.

The key benefit of this approach is that modifications happen before the request ever reaches your origin or the cloudflared connector. This means that the work is done entirely on Cloudflare's network, keeping your infrastructure lean. Also, header modifications can be integrated with your other Cloudflare services, like WAF Custom Rules, Rate Limiting, etc., because they all operate within the same request evaluation flow. You can also make use of Secrets Store and Workers Secrets to securely store sensitive information like API keys and auth tokens.

We're intentionally cautious about adding features to cloudflared that duplicate functionality already available at the edge. Our goal is for cloudflared to be a highly reliable, secure, and lightweight connector. Adding HTTP processing logic risks increasing its complexity and resource consumption over time, which runs counter to its primary purpose. By keeping this logic at the edge, we can ensure cloudflared remains focused on what it does best: creating a secure, persistent connection from your infrastructure to Cloudflare.

With that context in mind, we'd love to better understand the scenarios where edge-based rules fall short. Beyond quick tunnels, are there other specific situations where using Transform Rules is not feasible or practical?

[absar0920]

@nikitacano Thanks.

[Mercuria1x]

@nikitacano
Cloudflare automatically adds some request headers such as cf-connecting-ip, etc.
In some cases, I would like to manually remove these headers.

Currently, this can be done in Transform Rules, but if I deal request through Workers , the Workers service will add those headers again.