Tools tagged #developer
Every ecech. tool tagged developer: 61 free calculators and utilities across Date, Time & Timezone, Design & Color. No signup, runs in your browser.
.env Converter
There is no .env specification. Most libraries strip the quotes; Docker Compose's env_file historically kept them — and nothing logs why authentication failed.
Developer💻Base Converter
\u22125 is 11111011 in 8 bits and 11111111111111111111111111111011 in 32. Neither is more correct — the width is part of the answer.
Developer💻Base64 Encode / Decode
Text or files, both directions, with correct UTF-8 handling and a URL-safe toggle — plus the 33% size penalty shown before you paste a 4 MB image into a JSON payload.
Developer🎨Border Radius
The slash syntax gives each corner a separate horizontal and vertical radius, which is how organic shapes are made in CSS without touching SVG.
Design🎨Box Shadow Generator
Real objects cast a tight contact shadow and a soft ambient one. Stack two box-shadow values and the result stops looking like CSS.
Design💻Caesar Cipher
There are only 25 possible shifts, so breaking it takes no cleverness. Letter frequency finds the key on longer text without even trying them all.
Developer🌐CIDR Overlap Checker
10.0.0.0/8 and 10.1.0.0/16 look unrelated and one sits entirely inside the other. Paste a list and see which blocks collide, and which merely contain another.
Network🌐CIDR to IP List
A /24 is 256 addresses and 254 usable hosts. Get the explicit list, with the network and broadcast addresses labelled instead of quietly included.
Network💻Column Letters
A is 1 and Z is 26, so the next is AA rather than A0. That missing zero digit is why the obvious conversion gives the wrong answer.
Developer💻CSS Gradient Generator
Linear, radial and conic gradients with as many stops as you like — plus the fix for the muddy grey band that appears between complementary colours.
Developer💻CSV to JSON
Leading zeros are identifiers, long digit strings lose precision as numbers, and 03/04/2026 has two readings. This infers types and knows where to stop.
Developer💻cURL to fetch
Converts the command properly — quoted bodies, escapes, line continuations — and flags the headers a browser will silently drop on the way out.
Developer🕑Date Format Tester
In Unicode patterns YYYY is the week-numbering year. 31 December 2019 renders as 2020, which is where the New Year date bugs come from.
Time🕑Epoch Rollover
It does not crash. It wraps to minus two billion and reports a date 137 years in the past, which is far harder to notice.
Time🕑FILETIME Converter
The 18-digit number in a registry export or an Active Directory dump. Too large for a JavaScript number, so parsing it the obvious way loses digits.
Time✏️Find and Replace
Replacement strings have their own syntax, and .* grabs more than you meant. See every match highlighted before anything changes.
Text & SEO💻Float Precision
Every language stores 0.1 as something slightly larger. See the exact value, the 64 bits, and the gap to the next number that exists.
Developer💻Glob Pattern Tester
Test a pattern against your own file list in both dialects at once. node_modules and /node_modules are not the same rule, and that difference ships secrets.
Developer💻Hash Generator
Hashing is one-way with no key, so nothing can be decrypted from it. Useful for checking a file arrived intact — and the wrong tool for storing passwords.
Developer💻HTML Entities
Replace < before & and < becomes &lt;. Only five characters matter, and the order you replace them in is one of them.
Developer🕑HTTP Date Header
Expires and Last-Modified want \u201cMon, 10 Aug 2026 12:34:56 GMT\u201d \u2014 English month names, literal GMT, no milliseconds. Anything else is silently ignored.
Time💻HTTP Status Codes
301 and 302 may rewrite POST to GET and drop the body. 307 and 308 do not. Look up a code, or answer two questions and get the right one.
Developer💻ID Timestamp Decoder
Snowflakes, ObjectIds, ULIDs and UUIDv7 all carry the time they were made. Paste one and read the date — with the right epoch, which is where this usually goes wrong.
Developer💻Invisible Characters
Finds zero-width spaces, bidi overrides and non-breaking spaces — and says which are harmless formatting and which are used to watermark or disguise text.
Developer🌐IP Range Checker
Private, loopback, link-local, carrier-grade NAT, multicast and reserved — with what each one means when you find it somewhere unexpected.
Network🌐IP Range to CIDR
192.168.1.5 to 192.168.1.10 is four CIDR blocks, not one. Firewalls want CIDR and people think in ranges, so here is the exact conversion.
Network🕑ISO 8601 Date Format
Build a valid ISO 8601 string, or paste one and see exactly how it is interpreted — including why a date without a time lands in a different day.
Time🕑ISO 8601 Duration
The same letter M means month before the T and minute after it. Paste a duration to see the parts, and where a conversion to seconds is genuinely undefined.
Time💻JSON Escape
Seven characters become eleven, then nineteen. By the third level nobody can edit it by hand — which is the signal to stop nesting.
Developer💻JSON Formatter
Paste broken JSON and get the exact line and column that failed, with a human explanation of what the parser expected. Format, minify, sort keys and copy out.
Developer💻JSON Key Sorter
Key order means nothing to a parser and everything to git. Sorting recursively turns a reshuffled file back into a one-line diff.
Developer💻JSON Minifier
Minifying cuts a third of the raw bytes and almost none after gzip, because whitespace compresses away. This measures both, so you know if it is worth doing.
Developer💻JSON Size Analyzer
Total size says there is a problem. Per-key size says which one, and the answer is rarely distributed evenly.
Developer💻JSON to CSV
Nested objects become dotted columns. Arrays have no right answer, so you get both options and what each one loses. Quoting is handled properly.
Developer💻JSON to Go Struct
Go has no undefined, so a missing number and a zero look identical after Unmarshal. This generates the tags, exports every field, and says where a pointer is needed.
Developer💻JSON to TypeScript
A missing key and a null key are different types. Most generators emit any for both. This merges every array element first, then explains each decision.
Developer💻JSON to YAML
An unquoted NO is a boolean in YAML 1.1, and so are y, n, on and off. Version 1.10 becomes 1.1. Quoting is the only portable fix.
Developer💻JWT Decoder
A JWT payload is base64, not encryption — anyone holding the token can read it. Decode the claims, check the expiry, and see what the token is really telling you.
Developer💻Lorem Ipsum Generator
Classic lorem ipsum, plus placeholder data that behaves like the real thing — long names, awkward emails and prices that actually break your layout.
Developer🌐MAC Address Format
Convert between colon, dash, Cisco and bare formats, and read the two bits that say whether an address is multicast or a randomised one no vendor ever owned.
Network💻Markdown to HTML
Type Markdown, watch the HTML appear, copy either side. Escapes HTML by default, and tells you plainly which syntax it supports rather than dropping it silently.
Developer💻Meta Tag Generator
Twitter reads your Open Graph tags, so most twitter: tags do nothing. This writes only what is needed, makes og:image absolute, and shows the card before you ship it.
Developer💻Nano ID Generator
Generate cryptographically strong local IDs with a custom alphabet while measuring entropy, address space and birthday-bound collision risk.
Developer🖼️Placeholder Image
Every placeholder service sees the URL of every page that uses it. This makes the file in your browser instead, so nothing is requested and nothing breaks.
Image🕑Play Test Deadline
Calculate the earliest production-access date, track the twelfth tester and see how one dropout can reset that tester's continuous-day clock.
Time💻Regex Tester
Matches highlight as you type, capture groups are listed per match, and a runaway pattern is stopped before it hangs your tab instead of after.
Developer💻Screen & Viewport
Display scaling divides the physical resolution by the scale factor. Every web API reports the result, which is the number your layout actually gets.
Developer🕑Seconds to Duration
90061 seconds is 1d 1h 1m 1s. Paste a number to format it, or type a duration to get seconds back — with the zero components dropped.
Time💻Semver Comparator
String sorting puts 1.0.10 before 1.0.9 and 1.0.0-alpha after 1.0.0. Both are wrong. Compare versions properly and see what a caret range really allows.
Developer✏️Sort & Dedupe Lines
A plain sort puts 10 before 9. A plain dedupe keeps two lines that differ by a trailing space. Both are shown and both are fixable here.
Text & SEO💻SQL IN Clause Builder
Paste a column, get a working IN list — with quotes escaped the standard way and NULL pulled out, because NOT IN with a NULL matches nothing at all.
Developer💻SVG to CSS Background
Base64 makes an SVG 33% bigger and kills gzip. Percent-encoding only what CSS actually chokes on is smaller, still valid, and still readable.
Developer💻Text Diff Checker
Most diff tools show you two lines and let you hunt for the difference. This one marks the exact words, and never sends your text anywhere.
Developer📏Text to Binary
A is one byte, 中 is three, and a family emoji is eighteen. Convert both directions and see where the bytes actually go.
Converters🕑Timestamp Unit
1000000000 is September 2001 in seconds and January 1970 in milliseconds. Both parse, so validity cannot decide it. Here is every reading at once.
Time🕑Unix Timestamp Converter
Paste any epoch number and it works out whether you gave it seconds, milliseconds or microseconds — then shows the date in UTC, your local zone and every common format.
Time💻URL Encode / Decode
encodeURI leaves :/?&= alone; encodeURIComponent escapes them. One is for a whole URL, the other for a value inside it, and swapping them breaks different things.
Developer💻URL Slug Generator
Turn a headline into a clean, safe URL. Strips accents properly, keeps the words that matter, and tells you when a character cannot be transliterated.
Developer💻UUID Generator
Generate one or ten thousand at once, formatted for SQL, JSON, CSV or a plain list — from the browser's crypto RNG, not Math.random, which is the difference that matters.
Developer🌐VLSM Planner
A subnet must start on a multiple of its own size, so a large block placed after small ones can be blocked by a boundary while addresses remain.
Network🎥YouTube Video ID
Paste any YouTube link — watch, youtu.be, embed, Shorts, live, with or without a playlist attached — and get the clean 11-character ID plus every other URL form.
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