Seeded random string generator
Type a seed such as release-2026-08, ask for 24 characters, and you get DRWAF7foOYXgYWU4VpEGTuft every time you repeat those settings, so sample codes and demo data can be rebuilt exactly. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Length
- 24
- Seed
- release-2026-08
- Value
- DRWAF7foOYXgYWU4VpEGTuft
The seeded random string generator creates the same pseudo-random text whenever you provide the same seed, length, and character-set choices. Select lowercase letters, uppercase letters, numbers, symbols, or any useful combination, then reuse the seed when you need the exact result again. Generation is deterministic and local to the calculation: it does not consult a network service, system clock, or hidden random source.
Create repeatable strings from explicit inputs
A normal random-string tool is designed to give you a different answer each time. Enter an integer length, provide any non-empty seed, and choose the character sets that may appear. Repeating all of those inputs produces the same output character for character.
Changing even one option creates a different alphabet or pseudo-random sequence and can therefore change the result. Lowercase letters, uppercase letters, and numbers are enabled by default, while symbols are opt-in. You can disable any default group when you need a narrower format, such as digits for synthetic reference numbers or lowercase letters for compact labels.
At least one group must remain enabled because generating from an empty alphabet has no meaningful result. The returned object echoes the effective flags alongside the generated value, so saved results remain easy to audit and reproduce later.
Understand determinism and its security boundary
The generator hashes the supplied seed into a fixed 32-bit starting state and advances a specified integer pseudo-random algorithm once for every requested character. Each generated integer selects a position in the enabled alphabet. The character groups are joined in a fixed order, which means the same settings behave identically across supported environments rather than depending on object ordering, locale, time, or platform entropy.
A deterministic string is not suitable for passwords, access tokens, reset links, encryption keys, or any value whose safety depends on unpredictability. Anyone who learns or guesses the seed and settings can reproduce the output. Use a cryptographically secure random generator for secrets.
Use this capability when reproducibility, explainability, and stable test data matter more than resistance to guessing. The function never calls a system random source, reads the current date, or contacts an external service.
Choose seeds and character sets for reliable workflows
Treat the seed as a durable label for the scenario you want to reproduce. Store the seed together with the length and all four flags; the seed alone does not fully describe the result because changing the alphabet changes how generated integers map to characters. For structured test suites, derive seeds systematically, for example by combining a suite name with a case number, while avoiding personal or confidential data.
Select only the character groups accepted by the downstream system. Numbers alone work for mock numeric codes, letters and numbers suit portable identifiers, and the symbol option is helpful when testing parsers or escaping behavior. The maximum length is bounded at 4096 characters to keep execution and response size predictable.
What you can do with it
Publish reproducible examples
Use a recorded seed so documentation and tutorials can recreate the exact sample string shown to readers.
Exercise format constraints
Select specific character groups to test validation, escaping, import, or display behavior with predictable input.
FAQ
Will the same inputs always return the same string?
Yes. The seed, length, and all four character-set flags together determine the result.
Can I use the output as a password or security token?
No. The algorithm is intentionally reproducible, so its output is not cryptographically unpredictable and must not protect accounts or sensitive data.
Which character sets are available?
You can independently enable lowercase English letters, uppercase English letters, decimal digits, and common ASCII symbols.
What happens if I turn off every character set?
Nothing is generated: at least one group must stay on, because otherwise there is no alphabet to draw from. Lowercase, uppercase and numbers start switched on; symbols stay off until you enable them.
What do I need to save to get the same string again later?
Keep the seed, the length and the on or off state of all four character groups. The seed alone is not enough, because a different alphabet changes which character each step picks.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/prob/random-string-seeded \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"length":24,"seed":"release-2026-08"}'const res = await fetch("https://api.kit.forhosting.com/prob/random-string-seeded", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"length": 24,
"seed": "release-2026-08"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/prob/random-string-seeded",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"length": 24,
"seed": "release-2026-08"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/prob/random-string-seeded", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"length":24,"seed":"release-2026-08"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"length":24,"seed":"release-2026-08"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/prob/random-string-seeded", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"length": 24,
"seed": "release-2026-08"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "prob.random_string_seeded",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Understand determinism and its security boundary
This predictability is the feature: it lets a colleague, build server, browser session, or later API request reconstruct an identical string from the recorded inputs. It also creates an important boundary.
Choose seeds and character sets for reliable workflows
The price is $0.002 per request through the API, while the browser experience can run the same pure calculation directly.
Integration use cases
Build stable test fixtures
Generate repeatable names, codes, and field values that stay identical across local runs and continuous integration.
Technical questions
What happens if every character set is disabled?
The request returns an invalid-input error because there is no alphabet from which to generate characters.
How much does an API request cost?
Each API request costs $0.002. The browser tool can perform the same deterministic calculation locally.