Funkload - Web load testing, stress testing, and functional testing tool written in Python and distributed as free software under the GNU GPL. Emulates a web browser (single-threaded) using webunit; https support; produces detailed reports in ReST, HTML, or PDF.

Loadea - Stress testing tool runs on WinXP; free evaluation version for two virtual users. Capture module provides a development environment, utilizes C# scripting and XML based data. Control module defines, schedules, and deploys tests, defines number of virtual users, etc. Analysis module analyzes results and provides reporting capabilities.

TestLOAD - An automated load testing solution for IBM iSeries from Original Software Group Ltd. Rather than placing artificial load on the network, it runs natively on the server, simulating actual system performance, monitoring and capturing batch activity, server jobs and green-screen activity. For web and other applications.

NeoLoad - Load testing tool for web applications from Neotys with clear and intuitive graphical interface, no scripting/fast learning curve, clear and comprehensive reports and test results. Can design complex scenarios to handle real world applications. Features include data replacement, data extraction, system monitors, SSL recording, PDF and HTML reporting, IP spoofing, and more. Multi-platform: Windows, Linux, Solaris.

PowerProxy - A low cost HTTP/HTTPs proxy, from Orderly Software Ltd., has a range of basic load-testing features to test web servers and show debugging information about every request and response received or sent. For Windows.

webStress - Load and stress testing service from MoniForce BV. Includes recommendations on how to fix performance-related problems.

HostedToolbox - Hosted load testing service from hostedLABS, LLC. Browser based test script recording, no downloads or system requirements Works with any client or server. Executed from hostedLAB's distributed infrastructure with servers in multiple locations.

Test Complete Enterprise - Automated test tool from AutomatedQA Corp. includes web load testing capabilities.

WebPartner Test and Performance Center - Test tool from WebPartner for stress tests, load performance testing, transaction diagnostics and website monitoring of HTTP/HTTPS web transactions and XML/SOAP/WSDL web services.

QTest - Web load testing tool from Quotium Technologies SA. Capabilities include: cookies managed natively, making the script modelling phase shorter; HTML and XML parser, allowing display and retrieval of any element from a HTML page or an XML flux in test scripts; option of developing custom monitors using supplied APIs; more.

LoadDriver - Load test tool from Inforsolutions emphasizes ease of use; directly drives multiple instances of MSIE, rather than simulating browsers. Supports browser-side scripts/objects, HTTP 1.0/1.1, HTTPS, cookies, cache, Windows authentication. Tests can be scriptlessly parameterized with data from text files or custom ODBC data source, for individual userID, password, page to start, think times, data to enter, links to click, cache, initial cache state, etc.

Test Perspective Load Test - Do-it-yourself load testing service from Keynote Systems for Web applications. Utilizes Keynote's load-generating infrastructure on the Internet; conduct realistic outside-the-firewall load and stress tests to validate performance of entire Web application infrastructure.

SiteTester1 - Load test tool from Pilot Software Ltd. Allows definition of requests, jobs, procedures and tests, HTTP1.0/1.1 compatible requests, POST/GET methods, cookies, running in multi-threaded or single-threaded mode, generates various reports in HTML format, keeps and reads XML formatted files for test definitions and test logs. Requires JDK1.2 or higher.

httperf - Web server performance/benchmarking tool from HP Research Labs. Provides a flexible facility for generating various HTTP workloads and measuring server performance. Focus is not on implementing one particular benchmark but on providing a robust, high-performance, extensible tool. Available free as source code.

NetworkTester - Tool (formerly called 'NetPressure') from Agilent Technologies uses real user traffic, including DNS, HTTP, FTP, NNTP, streaming media, POP3, SMTP, NFS, CIFS, IM, etc. - through access authentication systems such as PPPOE, DHCP, 802.1X, IPsec, as necessary. Unlimited scalability; GUI-driven management station; no scripting; open API. Errors isolated and identified in real-time; traffic monitored at every step in a protocol exchange (such as time of DNS lookup, time to logon to server, etc.). All transactions logged, and detailed reporting available.

WAPT - Web load and stress testing tool from SoftLogica LLC. Handles dynamic content and HTTPS/SSL; easy to use; support for redirects and all types of proxies; clear reports and graphs.

Microsoft Application Center Test - Tool for stressing Web servers and analyzing performance and scalability problems with Web applications, including ASP, and the components they use. Supports several authentication schemes and SSL protocol for use in testing personalized and secure sites. The programmable dynamic tests can also be used for functional testing. Visual Studio .NET Edition.

OpenLoad - Affordable and completely web-based load testing tool from OpenDemand; knowledge of scripting languages not required - web-based recorder can capture and translate any user action from any website or web application. Generate up to 1000 simultaneous users with minimum hardware.

ANTS - Advanced .NET Testing System from Red Gate Software. A load and stress testing tool focused on .NET web applications, including XML Web Services. ANTS generates multiple concurrent users via recordable Visual Basic .NET scripts and records the user experiences, at the same time performance counter information from Windows system is integrated into the results.

Apache JMeter - Java desktop application from the Apache Software Foundation designed to load test functional behavior and measure performance. Originally designed for testing Web Applications but has since expanded to other test functions; may be used to test performance both on static and dynamic resources (files, Servlets, Perl scripts, Java Objects, Data Bases and Queries, FTP Servers and more). Can be used to simulate a heavy load on a server, network or object to test its strength or to analyze overall performance under different load types; can make a graphical analysis of performance or test server/script/object behavior under heavy concurrent load.

TestMaker - Free open source utility maintained by PushToTest.com and Frank Cohen, for performance, scalability, and functional testing of Web application. A framework and utility to build and run intelligent test agents that implement user behaviors and drive the system as users would. Features an XML-based scripting language and library of test objects to create test agents. Includes capability to check and monitor email systems using SMTP, POP3, IMAP protocols. Java-based tool - runs on any platform.

Webhammer - Low-cost utility by Stephen Genusa designed to test Web applications and servers. Configurable 1-16 connections per system CPU.

SiteStress - Remote, consultative load testing service by Webmetrics. Simulates end-user activity against designated websites for performance and infrastructure reliability testing. Can generate an infinitely scalable user load from GlobalWatch Network, and provide performance reporting, analysis, and optimization recommendations.

e-Load - Web load test tool from Empirix can simulate hundreds or thousands of concurrent users; accessible via a Web browser interface.

Siege - Open source stress/regression test and benchmark utility; supports basic authentication, cookies, HTTP and HTTPS protocols. Enables testing a web server with a configurable number of concurrent simulated users. Stress a single URL with a specified number of simulated users or stress multiple URL's simultaneously. Reports total number of transactions, elapsed time, bytes transferred, response time, transaction rate, concurrency, and server response. Developed by Jeffrey Fulmer, modeled in part after Lincoln Stein's torture.pl, but allows stressing many URLs simultaneously. Distributed under terms of the GPL; written in C; for UNIX and related platforms.

Jblitz - Affordable load testing tool from Clan Productions aimed at small web site developers. Each part of a site's functionality can be tested apart or together with up to 500 threads to simulate many users. Can request anything normally addressable through browser, including regular web pages, ASP scripts, JSP scripts, Servlets, CGI scripts etc.

WebServer Stress Tool - Web stress test tool from Paessler GmbH handles proxies, passwords, user agents, cookies and ASP-session IDs. Shareware. For Windows. Standard, Professional, and Enterprise versions.

Web Polygraph - Freely available benchmarking tool for caching proxies, origin server accelerators, L4/7 switches, and other Web intermediaries. Other features: for high-performance HTTP clients and servers, realistic traffic generation and content simulation, ready-to-use standard workloads, powerful domain-specific configuration language, and portable open-source implementation. C++ source available; binaries avail for Windows.

OpenSTA - 'Open System Testing Architecture' is a free, open source web load/stress testing application, licensed under the Gnu GPL. Utilizes a distributed software architecture based on CORBA. OpenSTA binaries available for Windows.

PureLoad - Java-based multi-platform performance testing and analysis tool from Minq Software. Includes 'Comparer' and 'Recorder' capabilities, dynamic input data, scenario editor/debugger, load generation for single or distributed sources.

ApacheBench - Perl API for Apache benchmarking and regression testing. Intended as foundation for a complete benchmarking and regression testing suite for transaction-based mod_perl sites. For stress-testing server while verifying correct HTTP responses. Based on the Apache 1.3.12 ab code. Available via CPAN as .tar.gz file.

Torture - Bare-bones Perl script by Lincoln Stein for testing web server speed and responsiveness and test stability and reliability of a particular Web server. Can send large amounts of random data to a server to measure speed and response time of servers, CGI scripts, etc.

WebSpray - Low-cost load testing tool from CAI Networks; includes link testing capabilities; can simulate up to 1,000 clients from a single IP address; also supports multiple IP addresses with or without aliases. For Windows.

eValid - Web test tool from Software Research, Inc that uses a 'Test Enabled Web Browser' test engine that provides browser based 100% client side quality checking, dynamic testing, content validation, page performance tuning, and webserver loading and capacity analysis.

WebPerformance Trainer - Load test tool emphasizing ease-of-use, from WebPerformance Inc. Supports all browsers and web servers; records and allows viewing of exact bytes flowing between browser and server; no scripting required. Modem simulation allows each virtual user to be bandwidth limited. Can automatically handle variations in session-specific items such as cookies, usernames, passwords, IP addresses, and any other parameter to simulate multiple virtual users. For Windows, Linux, Solaris, most UNIX variants.

WebSuite - A collection of load testing, capture/playback, and related tools from Technovations for performance testing of web sites. Modules include WebCorder, Load Director, Report Generator, Batch, Manager, and others. WebSizr load testing tool supports authentication, SSL, cookies, redirects. Recorded scripts can be modified manually. For Windows.

FORECAST - Load testing tool from Facilita Software for web, client-server, network, and database systems. Capabilities include proprietary, Java, or C++ scripting; windows browser or network recording/playback. Network traces can also be taken from over 15 third party tracing tools. Virtual user data can be parameterized. Works with a wide variety of platforms.

e-Load - Load test tool from Empirix Software; for use in conjunction with test scripts from their e-Tester functional test tool. Allows on-the-fly changes and has real-time reporting capabilities. Includes script editor with advanced debugging and maintenance capabilities. Works with a wide variety of platforms.

http-Load - Free load test application from ACME Labs to generate web server loads, from ACME Software. Handles HTTP and HTTPS; for Unix.

QALoad - Compuware's QALoad for load/stress testing of web, database, and char-based systems. Integration with other Compuware tools provides an in-depth view by monitoring its operating system, database and network components, as well as the application itself. Works with a variety of databases, middleware, ERP.

Microsoft WCAT load test tool - Web load test tool from Microsoft for load testing of MS IIS servers; other MS stress tools also listed.

Portent Web Load test tool - Loadtesting.com's low-priced web load testing tool. Has minimal hardware requirements. Page validation via matching string in page. Written in Java; multi-platform.

SilkPerformer - Enterprise-class load-testing tool from Segue. Can simulate thousands of users working with multiple protocols and computing environments. Allows prediction of behavior of e-business environment before it is deployed, regardless of size and complexity. SilkPerformer Lite version also available for up to 100 simulated users.

Radview's WebLoad - Load testing tool from Radview Software, also available as part of their TestView web testing suite. Capabilities include over 75 Performance Metrics; can view global or detailed account of transaction successes/failures on individual Virtual Client level, assisting in capturing intermittent errors; allows comparing of running test vs. past test metrics. Test scripting via visual tool or Javascript. Wizard for automating non-GUI-based services testing; DoS security testing.

Loadrunner - Mercury's load/stress testing tool for web and other applications; supports a wide variety of application environments, platforms, and databases. Large suite of network/app/server monitors to enable performance measurement of each tier/server/component and tracing of bottlenecks. Integrates with other Mercury testing and monitoring producs.