Free Random String Generator for Test Data, Custom Character Sets, Lengths, and Unique Batches
Generate non-secret random strings for test data, sample identifiers, mock records, games, and development exercises. Choose character classes, remove ambiguous characters, and create unique batches.
Generate random strings
How to use this tool
1. Set the rules
Choose the range, filters, list, or generation settings that match your real task.
2. Generate and inspect
Run the tool once, review the result and its summary, then adjust settings only if needed.
3. Save useful output
Copy, download, print, favorite, or keep a local history entry when you need a record.
Practical examples
Mock database IDs
Generate 20 alphanumeric strings of a fixed length for test records.
UI stress test
Generate longer strings to see how components handle wrapping and overflow.
Readable test codes
Exclude ambiguous characters and use uppercase letters plus digits.
12 useful features
1–128 character length
Built into this page for a faster, clearer workflow.
1–50 strings per batch
Built into this page for a faster, clearer workflow.
Lowercase toggle
Built into this page for a faster, clearer workflow.
Uppercase toggle
Built into this page for a faster, clearer workflow.
Digit toggle
Built into this page for a faster, clearer workflow.
Symbol toggle
Built into this page for a faster, clearer workflow.
Ambiguous-character filter
Built into this page for a faster, clearer workflow.
Deduplicated batch output
Built into this page for a faster, clearer workflow.
Character-set size summary
Built into this page for a faster, clearer workflow.
Combinatorial estimate
Built into this page for a faster, clearer workflow.
Copy/download/print
Built into this page for a faster, clearer workflow.
Local history
Built into this page for a faster, clearer workflow.
Reference table
| Setting | What it changes | Useful check |
|---|---|---|
| Character classes | Build the eligible character set | Select at least one class. |
| Length | Controls characters per string | Long strings are useful for layout stress tests. |
| Unique batch | Avoids duplicates in one run | It does not track uniqueness across future runs. |
Quality checklist
0 / 5 complete
Quick knowledge check
What is the best first check before using generated output?
Microlearning guide
Randomness can cluster
A fair random process can still create streaks, repeated patterns, or uneven-looking small samples.
Uniqueness changes the pool
Sampling without replacement prevents repeats but also reduces the remaining eligible choices after every pick.
Use the right scope
These are browser utilities for planning, learning, creative work, and test data—not audited draws or high-stakes systems.
Related tools
Frequently asked questions
Is this a password generator?
No. It is designed for non-secret test strings and mock identifiers, not passwords, API keys, tokens, or cryptographic secrets.
What does exclude ambiguous characters do?
It removes characters commonly confused visually, including 0/O and 1/l/I.
Can I use only digits or only letters?
Yes. Turn character classes on or off until the generated set matches your test-data needs.
What is the bits estimate?
It is a simple combinatorial calculation based on character-set size and length, not a security certification.
Can a later batch repeat an earlier string?
Yes. Uniqueness applies only within the current generated batch.