How random are the generated strings?

They use the browser's crypto.getRandomValues() — a cryptographically secure random number generator — not Math.random(), which is predictable and unsafe for secrets.

What character sets can I include?

Any combination of lowercase, uppercase, digits, and symbols, with an option to exclude ambiguous characters (0/O, 1/l/I) for strings humans must read or type.

How long should a secure random string be?

For secrets: 16+ characters mixing all sets (~95 bits of entropy at 16 chars) is a solid floor; 32 characters for API keys and tokens. Each additional character multiplies the search space.

Can I generate many strings at once?

Yes — bulk mode produces dozens or hundreds of strings in one click, one per line, for seeding test data, voucher codes, or ID lists.

Are the generated strings sent to a server?

No — generation runs entirely in your browser. No one, including this site, ever sees the strings you generate.

Random String Generator — Free Secure Random Strings

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Random String Generator — Secure Randomness on Demand

Passwords, API keys, webhook secrets, coupon codes, test fixtures — all need strings nobody can guess. This free generator produces them using the browser's cryptographically secure random source (crypto.getRandomValues), with full control over length and character sets, bulk generation, and an ambiguous-character filter for human-readable codes. Nothing leaves your device; no signup.

Entropy: How Strong Is Your String?

Length	Charset (95 printable)	Entropy	Practical meaning
8	all sets	~52 bits	crackable — avoid for secrets
12	all sets	~79 bits	good password floor
16	all sets	~105 bits	strong secret
32	letters+digits	~190 bits	API-key grade

Each extra character multiplies attacker cost by the charset size — length beats complexity tricks every time.

Why Math.random() Is Not Enough

JavaScript's Math.random() is a fast pseudo-random generator whose internal state can be reconstructed from observed outputs — fine for animations, catastrophic for secrets. Secure generation requires a CSPRNG, which is exactly what this tool uses. If you generate secrets in your own code, the same rule applies: crypto APIs, never Math.random().

Common Recipes

Password: 16–20 chars, all four sets.
API key: 32–40 chars, letters + digits (symbol-free survives URLs and headers).
Voucher codes: 8–10 uppercase + digits, ambiguous characters excluded, bulk mode.
Test data: any shape, bulk-generated for fixtures and load tests.

Free and Private

Generation is local and unlogged — the strings exist only on your screen until you copy them.

Random String Generator

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