Free Personality and Brain Tests

Human Benchmark — Test Your Brain

Reaction time, memory, typing and aim measured against millions of people.

Global 16-Personality MBTI Test

Free 16-personality type assessment taken by over 100 million people worldwide.

Big Five Personality Test (Free, Research-Grade)

The personality model psychologists actually use. Free, no email required.

unittest

(Python standard library) Unit testing framework.

Mensa IQ Challenge

The official taster test. Take it once and then argue about it forever.

Communications system achieves fastest laser link from space yet

MIT Lincoln Laboratory, in partnership with NASA Goddard Space Flight Center, built and designed a communications payload, TBIRD, which is demonstrating space-to-ground laser communications at unprecedented data rates.

go-template-playground

An interactive environment to create and test Go templates.

Hoppscotch — API Testing in a Tab

A fast open-source alternative to heavy desktop API clients.

Hacker News Simulator

Browse the latest posts on Hacker News Simulator. Unlike the real HN, all comments are generated by LLMs. Posts, links, and titles are still user-submitted.

tldraw

The fastest infinite canvas for sketching an idea and sharing the link.

Obsidian Canvas - Visualize your ideas

Obsidian Canvas gives you infinite space to research, brainstorm, diagram, and lay out your ideas.

Hookdeck

Develop, test, and monitor your webhooks from anywhere. 100K requests and 100K attempts per month with three days retention.

GrowthBook

Open source feature flag and A/B testing provider with built-in Bayesian statistical analysis engine. Free for up to 3 users, unlimited feature flags and experiments.

Turn an idea into a 48-hour test

Break any idea into customers, pain, revenue, risks, and a free first experiment.

My idea is [IDEA]. Identify: 1) three customer groups most likely to pay, 2) their sharpest problem, 3) a free 48-hour validation test, 4) three paths to first revenue, and 5) clear failure conditions. Put it in a table and challenge the riskiest assumption first.