Tools

Science

Computer

IPIP : The best IP geolocation database

Programming

General Tools

Choose an open source license : Simple way to choose a license
DevDocs : API documentation for multiple programming languages/tools in one place
regex101 : Online regular expressions tester and debugger

Python

strftime : Python strftime reference
ruff : An extremely fast Python linter and code formatter, written in Rust.

Document

General Tools

Convertio : Convert your files to any format (300+ formats supported)
WebPlotDigitizer : Web based tool to extract data from plots, images, and maps

PDF

cpdf : Command line tool to manipulate existing PDF files
ILovePDF : Every tool you need to work with PDFs in one place
pdftk : The PDF toolkit for doing everyday things with PDF documents
PDF2JPG : Free PDF to JPG online converter
Smallpdf : All-in-one easy-to-use online PDF tools

Image

ILoveIMG : Every tool you could want to edit images in bulk
Logoly : A simple online logo generator
Squoosh : Image compression web app provided by Google

Writing

Grammarly : Free writing assistant to check your grammar
IRIS citations : How to cite/acknowledge IRIS data