picfit is a reusable Go server to manipulate images (resize, thumbnail, etc.).
It will act as a proxy on your storage engine and will be served ideally behind an HTTP cache system like varnish.
It supports multiple storage backends and multiple key/value stores.
Convert plain text diagrams to images !
Kroki provides a unified API with support for BlockDiag (BlockDiag, SeqDiag, ActDiag, NwDiag), C4 (with PlantUML), Ditaa, Erd, GraphViz, Mermaid, Nomnoml, PlantUML, SvgBob and UMLet... and more to come!
RSSify some content sources:
Email: get your favorite newsletters or any other types of emails straight to your RSS reader.
Telegram channel: free your Telegram chat list from channels and read them via RSS instead.
HTTP webhook (for tech-savvy people): send HTTP requests to Notifier and read them via RSS. 
imgproxy is a fast and secure standalone server for resizing and converting remote images. The main principles of imgproxy are simplicity, speed, and security.
A simple, intuitive web app for analysing and decoding data without having to deal with complex tools or programming languages. CyberChef encourages both technical and non-technical people to explore data formats, encryption and compression.
I love newsletters, but I hate receiving e-mails. Call me an oldie, but I still use RSS feeds to read my news and e-mails for communication. And I prefer to keep those two separate.
Unfortunately, as newsletters have become popular, there are some great readings that are not available through RSS anymore. Kill the newsletter! exists to fill this gap.
This service converts newsletters into RSS feeds.
HTML2PDF is a HTML to PDF converter written in PHP.
It allows the conversion of valid HTML 4.01 in PDF format, and is distributed under OSL.
If you need to convert files from one markup format into another, pandoc is your swiss-army knife.
Convert your HTML documents to PDF.
Beautiful printing with simple CSS.
Prince is an ideal printing component for server-based software, such as web applications that need to print reports or invoices. Using Prince, it is quick and easy to create PDF files that can be printed, archived, or downloaded.