IIS Application Request Routing (ARR)
IIS Application Request Routing (ARR): A free, self-hosted IIS module for HTTP routing, balancing, monitoring, and caching. Ranked #29 of 31 in Load Balancing Software by our editors (6.4/10); pricing: Free plan; best for windows/IIS users needing free HTTP reverse proxying.
At a glance
- Editor score6.4 / 10
- PricingFree plan
- Best forWindows/IIS users needing free HTTP reverse proxying
- Free planYes
- Paid fromNone
- Layer 7 routingYes
- Facts checked24 Sep 2026
Where it wins
- Routes HTTP requests using URLs, headers, and server variables
- Offers selectable balancing algorithms, health checks, and client affinity
- Includes reverse-proxy routing and disk-based HTTP caching
Where it doesn't
- Requires Windows Server running IIS and the IIS URL Rewrite module
- Self-hosted only; it is not a managed service
- Focused on HTTP routing rather than broader load-balancing needs
Our verdict on IIS Application Request Routing (ARR)
IIS Application Request Routing (ARR) is a free, self-hosted IIS module that routes HTTP requests to content servers and distributes traffic across them. It is aimed at web server administrators and hosting providers already running Windows servers with IIS. The module can manage server farms in IIS Manager, making it relevant for teams that want request routing and balancing within an existing IIS environment rather than a separate hosted service.
ARR’s HTTP controls are its main strength. Rules can inspect URLs, headers, and server variables, while administrators can choose among multiple load-balancing algorithms. Health monitoring uses live traffic and URL tests; cookie-based client affinity can keep a client on a content server, and host-name affinity supports shared hosting. Reverse-proxy configurations and disk-based HTTP caching extend its role beyond distributing requests. These capabilities make ARR a fit for IIS-based HTTP workloads that benefit from centralized farm management and runtime statistics.
The deployment trade-off is a close tie to the IIS stack: ARR is installed on Windows servers running IIS and relies on the IIS URL Rewrite module for request inspection and routing rules. It is not a managed service, so the team operates the environment itself. Microsoft’s official page lists compatibility through IIS 10. For Windows/IIS users seeking free HTTP reverse proxying and balancing, ARR covers the core needs; teams wanting a managed option or balancing beyond its stated HTTP focus should consider alternatives.
IIS Application Request Routing (ARR) pricing
IIS Application Request Routing (ARR) fact sheet
| Free plan | Yes |
|---|---|
| Paid from | None |
| Managed service | No |
| Layer 7 routing | Yes |
| Layer 4 routing | Not verified |
| Global traffic management | Not verified |
| TLS termination | Yes |
| Backend limit | Not verified |
| Deployment | Self-hosted |
| Platforms | Windows |
| Support | Docs |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | Free plan |
| Website | iis.net |
| Facts checked | 24 Sep 2026 |
Alternatives to IIS Application Request Routing (ARR)
- AWS Elastic Load BalancingBroad Layer 4 and Layer 7 load balancing for AWS production environments.9.3
- Google Cloud Load BalancingA managed load balancer for global, regional, Layer 4, and Layer 7 traffic.9.2
- Alibaba Cloud Server Load BalancerA broad Alibaba Cloud balancing service with Layer 4/7 routing and a low published entry price.9.1
See all IIS Application Request Routing (ARR) alternatives →
Also listed in
Used IIS Application Request Routing (ARR)? Be the first to review it
The editor score above is our own research. What this page doesn't have yet is a reader's view — what you used IIS Application Request Routing (ARR) for, what worked and what didn't. No stars are seeded and no review is paid for; an editor reads every one before it appears.
Write a reviewTwo minutes · verified accounts only · read by an editor before it appears
Featured on iTechGuides
IIS Application Request Routing (ARR) is listed in our Load Balancing Software directory. Add the badge to your site — it links back to this page.
<a href="https://www.itechguides.com/products/iis-application-request-routing-arr/"><img src="https://www.itechguides.com/best/badge/iis-application-request-routing-arr.svg" alt="Featured on iTechGuides" width="230" height="46"></a>
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Advertiser disclosure: iTechGuides is reader-supported. We may earn a commission when you click some links. How we rank.
Last updated · How we research and update