Developer Utilities
Small developer utilities that save a trip to a random website. Encode and decode Base64, explain a regex, build UTM links, generate QR codes and vCards, and more — the everyday helpers. Free in your browser, and available by API when you need them in a script.
Decimal to fixed-point converter
Turn a decimal into the integer stored in a Q.n fixed-point format: 0.1 with 8 fractional bits stores 26, which really stands for 0.1015625, an error of…
Free · Runs in your browser
CIDR first and last usable host calculator
192.168.1.0/24 gives usable hosts 192.168.1.1 through 192.168.1.254, 254 addresses once the network and broadcast are set aside.
Free · Runs in your browser
Subnet prefix cheatsheet
A /24 is mask 255.255.255.0, wildcard 0.0.0.255, 256 addresses and 254 usable hosts: pick a range of prefix lengths and get one row per prefix, ready for exams…
Free · Runs in your browser
TCP flags decoder
0x12, or 18, is SYN plus ACK, not a lone SYN: type a flags byte in decimal, hex or binary to see every control bit by name, or list names such as SYN and ACK to…
Free · Runs in your browser
Expected hash collisions calculator
Hash 100 keys into 128 buckets and, on average, more than half the keys end up sharing a bucket, at a load factor of 0.78125.
Free · Runs in your browser
Binary heap parent index calculator
Enter a node's index and pick the numbering: in a zero-based heap, index 5 has its parent at 2, because the floor of 4 over 2 is 2.
Free · Runs in your browser
Quadtree capacity calculator
See how large a fully populated quadtree gets at a given depth, such as 8 cells per side, 64 leaves, 21 internal nodes and 85 nodes in total at depth 3.
Free · Runs in your browser
Identifier naming case detector
Type a name from your code and see which convention it follows: getUserName is camelCase and splits into get, user and name.
Free · Runs in your browser
SemVer version parser
Split a version such as 1.2.3-alpha.1+build.7 into major 1, minor 2, patch 3, prerelease alpha.1 and build build.7, checked strictly against SemVer 2.0.0.
Free · Runs in your browser
UUID to integer converter
550e8400-e29b-41d4-a716-446655440000 is the 128-bit integer 113059749145936325402354257176981405696: paste a UUID, a decimal integer or a hex string and get all…
Free · Runs in your browser
Hash table bucket count calculator
Plan 1,000 keys at a load factor of 0.75 and you need at least 1,334 buckets, which rounds up to 2,048 as a power of two.
Free · Runs in your browser
Amdahl's law calculator
A program that is 95% parallel runs about 5.93 times faster on 8 processors, not 8 times, and can never pass 20 times however many you add.
Free · Runs in your browser
ASCII converter
Turn one character into its decimal ASCII code, or a code from 0 to 127 back into its character: uppercase A is 65 and a space is 32.
Free · Runs in your browser
Base64 encoder decoder
One converter for both directions: “Ready when you are.” becomes UmVhZHkgd2hlbiB5b3UgYXJlLg==, and any standard Base64 turns back into readable text, emoji and…
Free · Runs in your browser
Binary to text converter
0100100001100101011011000110110001101111 decodes to Hello: every eight bits make one ASCII character, most significant bit first, and a missing bit or stray…
Free · Runs in your browser
Hamming code calculator
The data word 1011 encodes to 0110011: three even-parity bits go into positions 1, 2 and 4, and your four bits fill positions 3, 5, 6 and 7.
Free · Runs in your browser
Odd parity bit calculator
For 1010, which has two ones, the odd-parity bit is 1, giving 10101 with three ones. Paste a string of zeros and ones to get the bit that makes the total count…
Free · Runs in your browser
Password entropy calculator
A 12-character password drawn at random from 95 printable characters carries about 78.84 bits, rated strong.
Free · Runs in your browser
RAM latency calculator
Turn the CAS latency and clock on a memory kit into real time: CL16 at 1600 MHz, sold as DDR4-3200, takes 10 ns until the first word arrives.
Free · Runs in your browser
Schedule a webhook
Have a URL of yours called on a cron schedule, for a nightly report, a renewal check or a cache warm-up, without keeping a server or container alive just to…
$0.002
Schedule a delayed callback
Have your URL called after a wait you choose, from a few seconds up to 30 days: a reminder 24 hours before a trial ends, or an unpaid invoice cancelled after 30…
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Generate a regex
Describe what you need to match, such as a phone number in three formats or a log line with a timestamp and a severity, and get the regular expression plus the…
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Explain a regex
Paste a regular expression you inherited and get a plain-language walk-through of each piece: what every group captures, what each anchor requires and what each…
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Explain code
Paste a function you did not write and read what it actually does today, not what its name suggests: the logic it follows, how it handles errors, its side…
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Document your code
Send a source file and get it back with a docstring above every function, in a style your tools read, such as Google, NumPy, JSDoc or PHPDoc.
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Turn a question into SQL
Ask which customers had two or more refunds this quarter and get a runnable query built only from the tables and columns you supply, plus a short note on what…
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Generate unit tests
A suite can reach 90% line coverage and still never try an empty list: send your function and its framework, such as Jest or PyTest, and get a runnable test…
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Write a commit message
Paste a diff and get a commit message written from what actually changed, such as fix(auth): handle expired refresh tokens, with the type and scope picked for…
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Generate a README
Get a README drafted from the code you actually shipped: the generator reads the folder layout, dependency files, build and test scripts and license, then…
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