F->IT is an open source & easy to use web based FTP client that resembles Windows Explorer.
It supports:
- Drag and drop folders and files
- Edit highlighted source files
- Upload multiple files

Diagramo is an HTML5 diagram editor, which allows to make diagrams and flowcharts from within a web browser. It allows to create, edit and share diagrams, organizational charts, network diagrams and graphs.

You have no need to install any browser plugin or extension in order to use Diagramo.
Tweet! is an unobtrusive JavaScript plugin for jQuery to add twitter on your website. Its small and efficient script that will not slow down or pause your page while tweets are loading.

With Tweet!, you can:
- Customize look and feel with your own stylesheet
- Display tweets from multiple accounts!
- Display tweets from a twitter search, or from your own feed
- Display your avatar
Maki is a tool for web designers that helps the transition from design to HTML / CSS code. Maki lets you overlay design mock-ups in the browser and see the adjustments you need to make, and tweak away until they match.

Maki, for sure, is an effective way to keep developers and designers on the same page from start to finish, ensuring that the final website matches the design layouts clients have approved.
ImpressPages is an open source CMS that enables you to develop an effective and functional website quickly. ImpressPages offers a new approach towards the administration of web content.

Features:
- Easy drag and drop widgets interface
- Newsletter
- Smart copy & paste
- SEO friendly
- Multilingual
Lumzy is a free online quick mockup creation and rapid prototyping tool for software designers and developers with robust features, intuitive and clean interface.

You can add events to controls, place controls inside other containers and emulate your project with easy page navigation triggered by user actions.
Add participants to your project and chat within same window over the project. With project participants, you can edit a project online in realtime. When you drag a control, everyone connected sees the changes you just made.
TeamLab is an open-source software for business collaboration and project management. It allows you to use social networking tools such as blogs and forums, organize business tasks and milestones, as well as communicate with your team members via corporate IM.

Features
- Create and manage existing projects
- Tasks & Milestones management
- Chat with your colleagues in real-time
TeamLab is written in ASP.NET / MySQL and can be used as a hosted service or its open source alternative allows you to deploy it on your own servers.
If you’re building a multilingual website or application, you probably use language files. When you change content in one language file, you need to remember to update the other language files. Even with source control, this can get messy pretty quickly if you have many languages, many translators or a large site.
String was built to keep things organized. It can manage your language files – from PHP to PO to Rails to iPhone applications. You can now easily add languages and sections to your site. You can also invite users and control permissions.

String is free, with no project limitations. Invite as many users as you like. You’re free to extract all your data, close your project at any time and you can easily import and export projects.
Plaud.it is a free website stat & rank monitoring tool which provides multiple stats in one place and can play a vital role in the marketing strategy development.

It allows you to monitor multiple sites and check for stats such as Pagerank, Alexa Rank, Feedburner Subscribers and Twitter followers, etc.
Recommended: 10+ Website Speed & Performance Testing Tools & Plugins
Google Browser Size is a visualization of browser window sizes for people who visit Google. For example, the “90%” contour means that 90% of people visiting Google have their browser window open to at least this size or larger.
This is useful for ensuring that important parts of a page’s user interface are visible by a wide audience. And designers can use this tool to get better insights and user experiences for their websites and applications.

In the above example image, there is a donate now button which falls within the 80% contour, meaning that 20% of users cannot see this button when they first visit the page. 20% is a significant number; knowing this fact would encourage the designer to move the button much higher in the page so it can be seen without scrolling.