List of free developer-tools tool/service for developerππ½
Gradientos
Gradientos makes it easy to find gradients.
Tag: design, color-picker, colors, developer-tools

Firefox Developer Edition
Firefox Developer Edition is a version of Firefox that's tailored for web developers.
Tag: browser, developer-tools, web-development

DevPal
DevPal is a set of many online developer tools that make developers' everyday work productve
Tag: url-encoder, text-editor, dev, developer-tools, json, image, generator, encoder, decoder, formatter, productivity

Free PO editor
Free PO editor is a free online tool for translating Gettext PO files
Tag: text-editor, developer-tools, cloud-text-editor, i18n, localization

Warrant - APIs for authorization and access control
Hosted enterprise-grade authorization and access control service for your apps.
Tag: authorization, api, developer-tools, security
Free tier includes 5,000 API requests per month.
Responsively
A must-have DevTool for all Front-End developers that will make your job easier.
Tag: developer-tools, web-development, productivity, responsive, browser
Mirrored User-interactions across all devices. Customizable preview layout to suit all your needs. One handy elements inspector for all devices in preview. 30+ built-in device profiles with option to add custom devices. One-click screenshot all your devices. Hot reloading supported for developers.