Capture a full page screenshot in one keystroke
Scrolling and stitching by hand takes six screenshots and an image editor. This takes one keystroke.
Key Insights
ShareX is a powerful capture tool built for Windows desktops. Screenful lives entirely in the browser, so a full page capture works the same everywhere Chrome does.
The short version
Both tools capture more than the visible window, but they start from different places. Screenful is a browser extension that scroll stitches a full page in one keystroke, stays aware of sticky headers so they do not repeat down the finished image. Lets you annotate the result before saving as JPG or PDF. Nothing is installed beyond the extension itself. ShareX is a much broader Windows capture and workflow tool, with screen recording, file uploading and automation built in. It asks for an install and some configuration to get the most out of what it offers. Awesome Screenshot sits closer to Screenful, a browser based capture and annotate tool with its own following.
What actually separates them
The difference is scope and reach. Screenful does one job, full page capture. Does it from a keystroke with no separate application to open, which also means it works on any operating system Chrome runs on rather than one platform. ShareX does far more: region capture, scrolling capture, recording, uploads and workflow automation are all included. It is Windows only, and that breadth is more setup than most people need for a single full page screenshot. Awesome Screenshot covers similar browser based ground with its own annotation and screen recording tools layered on top.
What you get free
Screenful is $0, free with no account needed, and asks for 4 permissions on install: active tab, scripting, storage and clipboard write. ShareX is free and open source, and its cost is the time spent learning its options rather than money. Awesome Screenshot offers a free tier and reserves extra cloud storage and recording length for its paid plan.
Strengths and weaknesses
Verdict

Full-page screenshots in one keystroke

Screenful wins for anyone who needs full page, sticky header aware screenshots without extra software.
Who should pick what
Someone who needs a clean full page screenshot right now, on any platform, should install Screenful and press the shortcut. A Windows user who wants a complete capture and recording toolkit with automation built around it should learn ShareX instead. Awesome Screenshot suits someone who also wants screen recording bundled into the same browser tool.

Absolute beast