Web routing and reverse proxies: connecting external pages to your root domain

Marketing teams often need to launch landing pages on Webflow, run quizzes on Typeform, or set up storefronts on Shopify.

When requesting to host these pages under a root path like brand.com/special-offer, teams often encounter roadblocks:

• SaaS builders rarely support hosting directly in arbitrary subdirectories of an existing domain out of the box.
• Custom Nginx rules require engineering time, SSL certificate management, and asset rewriting.
• Tasks get stuck in development backlogs.

Teams often default to subdomains (offer.brand.com), which fragments cross-domain attribution and resets 1st-party cookies.

Edge Reverse Proxy technology enables co-locating third-party builders onto root domain subdirectories without writing custom server configs.

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1. How an edge reverse proxy works#

In a direct setup, the browser connects to the third-party builder. With an Edge Reverse Proxy, an intelligent edge router sits between the visitor and external SaaS tools:

Visitor opens: brand.com/black-friday
                     │
                     ▼
           [Sply Edge Gateway]
                     │
                     ├── Matches rule: path /black-friday ➔ Webflow Project #4819
                     ├── Fetches HTML upstream from webflow.io in 30 ms
                     ├── Rewrites asset URLs and Set-Cookie headers to brand.com
                     └── Delivers page seamlessly under your 1st-party domain

Technical mechanics:#

1. Unified root domain: visitors see clean URLs like brand.com/black-friday.
2. 1st-party context preservation: the browser treats the page as originating from your primary domain. All cookies (Client ID, UTM parameters, cart tokens) remain accessible.
3. Automatic SSL provisioning: the edge gateway provisions and renews SSL certificates across all proxied paths.

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2. Reverse proxy deployment methods#

Criterion	Manual Nginx / Apache	Cloudflare Workers	Sply Visual Router
Setup complexity	High (custom server configs)	Medium (writing JS code)	3 clicks in UI
SSL management	Manual Certbot / reload	Managed within CF	Fully automated
Cookie & header rewriting	Complex proxy_cookie_domain	Manual regex header parsing	Built-in out of the box
Self-serve for marketers	No (engineering-dependent)	No (engineering-dependent)	Yes

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3. Practical co-location use cases#

1. Campaign landing pages (Webflow, Tilda, Unbounce)#

Build pages in visual editors and publish them directly to brand.com/promo. Traffic remains on your primary domain, preserving attribution parameters.

2. Multi-step lead quizzes (Typeform, Marquiz)#

Host interactive forms at brand.com/quiz. Upon completion, users redirect to your main catalog (brand.com/shop) with their session state intact.

3. Headless storefronts and SaaS portals#

Attach external tools (booking systems, calculators) to brand.com/portal, serving them under your branded domain.

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Next steps#

• Step-by-step blueprint: Attaching Any External Landing Page to a Root Subdirectory in 3 Minutes.
• Next in series: Routing external landing pages to your root domain via the Sply dashboard.