Tools for Developers & IT Pros
138 toolsNetwork diagnostics, browser testing, and hardware validation tools. DNS lookup, IP analysis, system diagnostics, display calibration, and accessibility checking.
ZX Spectrum tape
ZX Spectrum tapes in your browser: TZX/TAP to audio for loading into a real Spectrum, cassette recordings back to TAP, tapes from your own BASIC.
AI prompt generator
Ready-made prompts for photos, chat, video and music, plus a builder that assembles your own prompt part by part and shows what is missing.
Country flags
An online tool for the flags of the world: filter by color, check the proportion and color codes, download PNG or SVG — or set the cloth waving in the wind.
Delay-line reservoir computing
Move the feedback gain and watch the reservoir’s memory change.
Font converter
Convert TTF, OTF, WOFF and WOFF2 in any direction, subset by language, pin variable axes and repair vertical metrics. Runs in the browser.
Color Picker from Photo
Upload a photo and drag across it — the loupe shows the exact pixel while the tool reads the color in six formats, names the shade and finds the nearest RAL.
SSL certificate decoder
Read any X.509 certificate: expiry, SAN, issuer, key strength, chain. Explains what is wrong, not only what the fields say.
CSR generator
Create a certificate signing request and its private key in your browser. RSA or ECDSA, every domain in the SAN, no openssl needed.
Self-signed certificate generator
Make an HTTPS certificate for localhost or an internal host. Builds a local CA so the browser warning goes away for good.
Key and certificate matcher
Check whether a private key belongs to a certificate or CSR. Works with RSA and EC, encrypted keys and .pfx bundles.
Certificate format converter
Convert certificates and keys between PEM, DER, PKCS#8, PKCS#1 and PFX. Opens old Windows .pfx exports other tools reject.
Certificate chain fixer
Paste your certificates and get a correctly ordered chain file. Finds the missing intermediate and downloads it for you.
Let’s Encrypt troubleshooter
Find out why certbot cannot validate your domain. Checks DNS, the challenge path over HTTP and your CAA records from outside.
File diagnosis
Drop the file that will not open — we walk its structure and tell you what is wrong with it.
File Converter
Audio, video, images, PDF, archives, subtitles and data files — one tool detects what you dropped and shows every format it can become.
Photo merger: two pictures into one
Combine two or more photos into one image: side by side, stacked, in a grid, or layered with transparency. Tone matching and before/after labels.
Lorem Ipsum
Generate placeholder text in 10 languages — exact word or character count, HTML, Markdown or plain. Presets for meta, tweet, SMS.
Face Maker
Drag the sliders to morph the head shape, set the expression and pose, then download a PNG — all in your browser.
Video Analyzer
Inspect any video file in your browser: codec, resolution, real bitrate, HDR, color, audio tracks and platform-readiness checks. Free.
Color Mixer
Mix two or more colors and see the real result — like real paint (blue + yellow = green), as light, or digital. In your browser.
Solid Color Screen
Fill your entire display with any solid color — presets, HEX/RGB/HSL, brightness, color temperature, and one-click edge-to-edge fullscreen.
Secret Language
Type a secret, get innocent-looking text to send anywhere; paste it back to recover the exact message.
Document scanner
Photograph a page with your phone — the edges are found for you, the perspective is straightened, the shadows go, and out comes a PDF that will be accepted in place of a scan.
Profanity Filter
Check any text for profanity and censor swear words across 10 languages.
