See Also

Appweb™ — for Dynamic Web Applications

red Appweb is an embedded web server for the efficient hosting of web applications and frameworks. It is blazing fast and has an extensive set of features. Appweb is optimized for hosting dynamic web applications via an event-driven, multi-threaded core to deliver rapid response, fast throughput and effective memory utilization. It is compact and will embed using as little as 800K of memory.

Appweb has a strong set of features including: SSL, TLS, basic and digest authentication, virtual hosting, loadable modules, Apache style configuration, PHP, Ejscript, CGI, sandbox resource limits, logging, angel monitoring process and extensive conditional configuration and compilation controls.

As one of the most widely deployed embedded web servers, Appweb is being used in networking equipment, telephony, mobile devices, consumer and office equipment as well as hosting for enterprise web applications and frameworks. It runs equally well stand-alone or in a web farm behind a reverse proxy such as Apache.

Appweb Benefits and Features:

Target Uses

Embedded Device Applications


When used in embedded devices or applications, web servers must assume they are secondary to the essential functions the device or application must perform. As such, the web server must minimize its resource demands and should be deterministic in the load it places on a system.

Appweb excels in this regard and is:

Web Applications Behind Reverse Proxies

Ruby and PHP have transformed the landscape for developing web 2.0 applications. They have made many tasks easier, but deploying these applications has not been quite so smooth. The "dirty-little-secret" about using these web frameworks is that deployment is often messy and difficult.

CGI, FastCGI, Mongrel-Clusters ... many solutions have been tried. More recently, the best solution is emerging — to deploy these applications behind a reverse proxy. This permits the front-end web server to exclusively serve static content and route the incoming requests. The back-end can then focus on actually running the application.


Appweb is an ideal back-end web server in this scenario for running web applications. Because Appweb is a fast, multi-threaded, event-driven server, each Appweb instance can host several web application sessions for maximum efficiency and minimal memory footprint. Due to its Apache compatible configuration file, you don't have to learn a whole new configuration setup. Using this configuration, you will lighten the load on your web installation, provide better response to clients and simplify your configuration.

Goals and Non-Goals

The goal of Appweb is to create the best web server for hosting web applications and frameworks whether they be embedded device applications or enterprise applications behind a reverse proxy. This requires that Appweb be:


Non Goals: Appweb was designed to handle small loads exceptionally well. An explicit goal was NOT to create a single, monolithic, highly scalable web server, like Apache, rather Appweb is designed to host the applications that will serve those users running behind Apache as a reverse proxy.

Appweb Internals

The core of Appweb is an event-driven, multi-threaded HTTP pipeline above which modules are loaded to provide content specific handling and to extend its functionality.


Appweb has the following features:

Request Pipeline

Appweb has an efficient, zero-copy request pipeline to process requests and generate responses. This consists of a mechanism of queues, packets, buffering and event scheduling. The pipeline architecture is highly optimized and uses sendfile, async I/O and vectored, scatter/gather writes to the network to avoid the costly aggregation of data and headers in a single buffer before writing to the network. pipeline


Most web servers have become more secure by a painful process of discovery. While it is no guarantee, developing a web server to be secure by design is easier than trying to engineer-in security after the fact. Securing embedded web servers is even more difficult, as it must be done without increasing memory footprint or degrading performance.

Embedthis Portable Runtime (MPR)

Appweb is designed to be secure from the foundation up, by using a secure Portable Runtime (MPR). The MPR is a cross-platform layer that permits over 97% of the Appweb code to be portable. It includes many mechanisms to assist in the creation of secure application. One such facility is a safe string and buffer handling module to help eliminate buffer overflows that have plagued many products.


Appweb closely controls its use of system resources via a technique known as "sandboxing". This means running the web server within tightly controlled limits so that request errors will not compromise system operation. Appweb has also been hardened against several common denial of service attacks.

Appweb can be configured to:

To build on this foundation, Appweb also provides a Secure Sockets Layer and Digest authentication.

Open Source and Free

osiAppweb uses an Open Source development model where a community of developers contribute toward making Appweb the leading embedded HTTP web server. Products are licensed under the GNU open source license and are provided with full source code. Embedthis Software has generously provided infrastructure, developers and funding to make this possible. Embedthis sells commercial support and licenses for Appweb.

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