Identifiers
Choose a value type and generate a batch. A seed repeats test values; passwords always use secure randomness.
Secure mode uses Web Crypto. Each click draws a new batch; editing options does not generate automatically.
Input is processed in this browser and is not sent to a server.
Length counts Unicode code points. Custom pools are deduplicated; at most 256 distinct points and 4,096 input code units. Whitespace and controls are rejected.
1–1,000 values. String/byte length 1–1,024. For length-based types: count × length ≤ 100,000.
Choose settings, then generate.
A random string generator is useful when a failing test needs the same inputs tomorrow, while a fresh password needs the opposite property. Choose the source explicitly, keep the parameters with your test case, and generate each batch only when you are ready.
The random string generator separates two jobs: a seed rebuilds the same test sequence, while secure mode draws new values from Web Crypto. Selecting password mode forces the secure source. Changing the seed, length or type leaves your previous output visible but disables export until you generate again.
A request for 16 bytes creates 16 values between 0 and 255. Hex displays those bytes as 32 lowercase digits, including leading zeros. With the same seed and length, both views describe the same bytes, so you can check an encoding fixture without confusing byte count with text length.
Use seeded mode for regression fixtures, and keep the exact seed, character pool and range. Every run restarts that sequence. Spaces in a nonempty seed matter; the page does not secretly add the current time.
String length counts Unicode code points; hex and bytes count raw bytes. For numeric or date tests, both bounds are included. The preset example loads three seeded strings of length 12 after you review the replacement.
Changing any parameter marks the result stale. Generate again with the button or Ctrl/Cmd + Enter before copying. The preview shows 50 values first, but both downloads always contain the entire current batch.
Select letters, digits, alphanumeric, URL characters or a custom pool. Duplicate code points in the pool are removed before drawing, so repeating a character does not weight it. Visible Unicode code points are accepted; whitespace, control and formatting characters are rejected.
The random number generator samples integers from an inclusive interval within the signed 32-bit range. Rejection sampling avoids modulo bias for intervals such as 0–100. Each draw is independent: equal bounds intentionally produce a repeated constant, and a batch may contain duplicates.
The random password generator uses Web Crypto and requires at least one uppercase letter, lowercase letter, digit and symbol. It draws a whole candidate uniformly and rejects candidates missing a class. Length is 8–128; this mode never accepts a seed.
Dates are calendar days in UTC, not local timestamps. IPv4 stays in 192.0.2.1–192.0.2.254, IPv6 uses 2001:db8::/32, and MAC addresses set the local and unicast bits. These are test values; no address is contacted or checked for availability.
Random bytes appear as decimal arrays and random hex as lowercase text. TXT has one value per line; JSON keeps integers, booleans and byte arrays in their original types. A boolean draw has equal probabilities, without promising an exact half-and-half split for a finite batch.
Secure mode uses the browser’s cryptographic random source and rejection sampling. It fails with an error if that source is unavailable; it does not fall back to a seed or Math.random. Seeded mode is deliberately reproducible and is suitable for test fixtures, not credentials.
Choose the Password type. It switches to secure mode and enforces all four character classes, with a default length of 16. The generic String type only samples its selected pool and does not guarantee those classes. Store real credentials in a password manager and avoid copying them into test logs.
The presets cover English letters, digits, their combination and URL-safe characters. Custom pools support visible Unicode code points, remove duplicates and reject whitespace and control characters. The password mode has a separate fixed pool with mandatory uppercase, lowercase, digit and symbol coverage.
Yes. Set the count from 1 to 1,000, subject to the combined 100,000-unit limit for length-based outputs. Preview expansion only affects what is displayed. Copy, TXT and JSON include every generated value, and parameter changes disable them until a new batch succeeds.
This page creates raw strings, byte values and other test data. It does not register an API key with any service or attach permissions, an expiration date or revocation. A generated string becomes an actual credential only when your own system provisions and manages it.
Have a question about a result?
Use the random string generator to create values with an explicit source, length and format. Save the exact seed and settings alongside reproducible tests; keep password output out of shared fixtures.