Useful Sites — new entries

SitePatent

2026-11-04T14:43:54Z

Curated web directory showcasing independent websites and digital products; relies on editorial selection rather than algorithmic feeds.

https://sitepatent.com

A Guide to Python's Magic Methods

2026-10-18T00:00:00Z

A classic guide that groups and explains Python's special (dunder) methods such as __init__, __getattr__ and __enter__ with examples. Unlike the language reference it shows how and when to use each group.

https://rszalski.github.io/magicmethods/

wtfpython

2026-10-18T00:00:00Z

A collection of surprising and counter-intuitive Python behaviours, each as a short snippet with an explanation. Unlike standard tutorials it teaches by letting you fall into the trap first and then see why.

https://github.com/satwikkansal/wtfpython

Beej's Guides

2026-10-18T00:00:00Z

Long-maintained, free and witty guides to C and network (socket) programming, offered as HTML, PDF and print. Unlike reference documentation they are written in a teaching voice.

https://beej.us/guide/

Operation Costs in CPU Clock Cycles

2026-10-18T00:00:00Z

The well-known infographic with explanation of the CPU clock-cycle cost of operations such as addition, memory access, branch mispredict and virtual calls. It gives orders of magnitude for performance intuition, not exact measurements.

https://6it.dev/blog/infographics-operation-costs-in-cpu-clock-cycles-741

os-tutorial

2026-10-18T00:00:00Z

A step-by-step tutorial that goes from a bootloader up to a kernel, one short folder per step. Shorter and more hands-on than books; it targets BIOS-based 32-bit x86. Maintenance is slow.

https://github.com/cfenollosa/os-tutorial

The Little Book About OS Development

2026-10-18T00:00:00Z

A free book on writing a simple x86 operating system from scratch: booting, memory, interrupts, system calls. Unlike large OS textbooks, it builds one small kernel from start to finish.

https://littleosbook.github.io/

Write your Own Virtual Machine

2026-10-18T00:00:00Z

A one-page tutorial on writing a virtual machine for the LC-3 architecture in C, ending with real LC-3 programs running. Unlike architecture lectures, it produces a working executor in a few hundred lines.

https://www.jmeiners.com/lc3-vm/

Front-End Checklist

2026-10-18T00:00:00Z

A checklist of items to verify before launching a web page across HTML, CSS, JS, accessibility, performance and SEO, with priority labels. Unlike general guides it is a tickable, prioritised checklist.

https://github.com/thedaviddias/Front-End-Checklist

Mozilla Web Security Guidelines

2026-10-18T00:00:00Z

Mozilla's recommended security headers and settings for websites: CSP, HSTS, cookie flags, CORS, SRI. It gives a priority and an example configuration for each, making it more actionable than general security articles.

https://infosec.mozilla.org/guidelines/web_security.html

NGINX Config Generator (nginxconfig.io)

2026-10-18T00:00:00Z

A form-driven generator that builds a ready NGINX config from domain, PHP/Node, security and performance options. Compared with copying sample configs, it adds best-practice settings (TLS, headers, gzip) automatically.

https://www.digitalocean.com/community/tools/nginx

Protomaps

2026-10-18T00:00:00Z

An open-source map stack that serves a world basemap as a single PMTiles file; the file sits on plain storage such as S3 and the browser reads only the parts it needs through HTTP range requests. Unlike hosted map services such as Mapbox there is no tile server and no per-use fee.

https://protomaps.com/

The A11Y Project

2026-10-18T00:00:00Z

A community-run accessibility site with a plain checklist based on WCAG, articles and lists of tools and resources. Unlike the W3C quick reference it states the criteria as items a developer can follow rather than in standards language.

https://www.a11yproject.com/

WAVE

2026-10-18T00:00:00Z

WebAIM’s accessibility evaluation tool; given an address, or through its browser extension, it overlays errors, alerts and structural information as icons on the page. Unlike scanners that produce a report it shows each problem in place on the page; the extension also checks pages behind a login, locally.

https://wave.webaim.org/

WCAG 2.2 Hızlı Başvuru

2026-10-18T00:00:00Z

The W3C’s “How to Meet WCAG” page: every success criterion, its level (A, AA, AAA), the techniques that satisfy it and the common failures, filterable by level and topic. Unlike reading the standard itself it takes you from a criterion straight to a technique you can apply.

https://www.w3.org/WAI/WCAG22/quickref/

WebAssembly

2026-10-18T00:00:00Z

The official site of the WebAssembly standard: the specifications, an introduction to the concepts and a feature table showing which proposal is supported in which browser and runtime. Unlike MDN’s WebAssembly pages it looks from the standard and the runtimes rather than from the JavaScript side.

https://webassembly.org/

webhint

2026-10-18T00:00:00Z

An open-source linter that scans a site for accessibility, speed, security and compatibility problems and explains each rule; it runs as an online scan, a CLI and a VS Code extension. Unlike Lighthouse it documents every rule in detail and is configurable.

https://webhint.io/

Enable CORS

2026-10-18T00:00:00Z

A small reference site that explains CORS with copy-paste configurations for dozens of servers and frameworks (Apache, nginx, Node, IIS and more). Unlike general HTTP docs it answers the narrow question of how to turn CORS on for a given server.

https://enable-cors.org/

HTTPie

2026-10-18T00:00:00Z

A readable alternative to curl that sends HTTP requests with coloured JSON output and a simple syntax. Unlike curl it needs far fewer characters for typical API calls; desktop and web apps exist too, and some of those ask for an account.

https://httpie.io/

Hurl

2026-10-18T00:00:00Z

A command-line tool that runs HTTP requests and checks their responses (status, JSONPath, XPath, headers) from plain-text files, usable as tests in CI. Unlike Postman collections the files stay readable in git.

https://hurl.dev/

The C10K problem

2026-10-18T00:00:00Z

The classic article on how one server can handle ten thousand concurrent connections (select/poll, epoll, threading models, kernel support). It explains historically why modern event-loop and async servers are designed the way they are. Unlike the docs of modern async frameworks, it explains the historical reason for the design.

https://www.kegel.com/c10k.html

Wasmer

2026-10-18T00:00:00Z

A WebAssembly runtime that lets you choose between several compiler back ends (Singlepass, Cranelift, LLVM), with a package registry and paid Wasmer Edge hosting alongside. Unlike Wasmtime it is not only a runtime but a commercial platform covering packaging and deployment too.

https://wasmer.io/

Wasmtime

2026-10-18T00:00:00Z

The Bytecode Alliance’s runtime for running WebAssembly outside the browser; written in Rust, compiling with Cranelift, and among the first to implement WASI and the component model. Unlike Wasmer it sells no package registry or hosting; it focuses on tracking the standards and on being embedded.

https://wasmtime.dev/

PostgreSQLCO.NF

2026-10-18T00:00:00Z

Searchable documentation for every postgresql.conf parameter, with version differences, defaults and community recommendations. Unlike the official manual it adds per-parameter tuning advice and context.

https://postgresqlco.nf/doc/en/param/

Select Star SQL

2026-10-18T00:00:00Z

An interactive online book that teaches SQL through exercises run in the browser against one real dataset. Unlike syntax references it builds query reasoning step by step around a single dataset's story.

https://selectstarsql.com/

Awesome Sites to Test On

2026-10-18T00:00:00Z

A list of target sites and APIs for practising test automation: demo shops, forms, trap-laden pages and fake APIs, grouped by kind. Rather than repeating dozens of interchangeable demo sites, this directory keeps a few representatives and points here for the rest.

https://github.com/BMayhew/awesome-sites-to-test-on

badssl.com

2026-10-18T00:00:00Z

A test site that serves subdomains with deliberately broken TLS setups (expired, self-signed, wrong host and so on). It tests clients, not servers: whether your browser or HTTP library rejects these errors correctly.

https://badssl.com/

CryptCheck

2026-10-18T00:00:00Z

A French test site that grades the TLS setup of HTTPS, SMTP and XMPP servers by cipher suite, certificate and key exchange. Unlike SSL Labs it covers mail and messaging servers as well as web.

https://cryptcheck.fr/

CSP Evaluator

2026-10-18T00:00:00Z

A Google tool that flags bypassable rules (unsafe-inline, broad wildcards, missing directives) when you paste in a Content-Security-Policy header. securityheaders.com grades headers in general; this looks only at the CSP, directive by directive, from an XSS angle. Unlike general header graders, it looks only at the CSP, directive by directive.

https://csp-evaluator.withgoogle.com/

Hardenize

2026-10-18T00:00:00Z

A scanner that gathers a domain's DNS, email (SPF/DKIM/DMARC), TLS and web-header security into one report. Unlike tests that measure a single layer it shows the whole external surface together; a public one-off scan is free, continuous monitoring is paid.

https://www.hardenize.com/

How's My SSL?

2026-10-18T00:00:00Z

A page that grades your browser's TLS client setup (version, cipher suites, known weaknesses). SSL Labs tests a server; this tests your side, the browser and OS, and the result is also available as a JSON API. SSL Labs tests a server, whereas this checks the client side.

https://www.howsmyssl.com/

MDN HTTP Observatory

2026-10-18T00:00:00Z

Mozilla's in-browser checker that scores a site's headers, cookies and TLS settings against security best practice; it now lives inside MDN. Unlike securityheaders.com it keeps a rescan history and is backed by an open-source scanner (http-observatory).

https://observatory.mozilla.org/

Security Headers

2026-10-18T00:00:00Z

A browser-based scan that grades a site's HTTP response headers (CSP, HSTS, X-Frame-Options, Permissions-Policy and so on) from A to F and explains what is missing. SSL Labs looks at the TLS layer; this looks at header hardening at the application layer. Instead of the TLS layer, it looks at application-layer header hardening.

https://securityheaders.com/

Static Analysis Tools

2026-10-18T00:00:00Z

A compilation of static analysis tools, linters and formatters grouped by language and format (formerly awesome-static-analysis). It is for surveying the options for a language rather than documenting a single tool.

https://github.com/analysis-tools-dev/static-analysis

Awesome GIS

2026-10-18T00:00:00Z

A list for geographic information systems: cartographic tools, geoanalysis libraries, data sources and communities. Unlike Esri-centred lists it is open-source and platform-neutral, with desktop GIS, web mapping libraries and open data in one place.

https://github.com/sshuair/awesome-gis

kepler.gl

2026-10-18T00:00:00Z

An open-source tool, born at Uber, for visualising large location datasets (millions of points, trips, grids) layer by layer in the browser. Unlike QGIS it aims at exploration and presentation rather than analysis: drop in a CSV or GeoJSON and you have a map with a time slider in minutes.

https://kepler.gl/

Map of Reddit

2026-10-18T00:00:00Z

Interactive WebGL map clustering subreddits by shared commenters (2020-21 comments). Unlike subreddit lists, it shows how communities relate spatially.

https://anvaka.github.io/map-of-reddit/

OpenDigger

2026-10-18T00:00:00Z

X-lab's analysis platform publishing open-source health metrics derived from GitHub activity (OpenRank, activity, contributors). Unlike the raw GitHub API, the metrics come ready-made as open time-series data.

https://open-digger.cn/en/

overpass turbo

2026-10-18T00:00:00Z

A web front end for querying OpenStreetMap data through the Overpass API; it shows the result on a map, downloads it as GeoJSON and has a wizard for those who do not write queries. Unlike downloading a full OSM extract it fetches only the features you ask for, such as every pharmacy in a city.

https://overpass-turbo.eu/

QGIS

2026-10-18T00:00:00Z

An open-source desktop GIS for Windows, macOS and Linux; it reads and analyses shapefile, GeoPackage, PostGIS and raster layers and extends through plugins. Unlike ArcGIS there is no licence fee; in exchange support comes from the community and commercial partners.

https://qgis.org/