Generate sequential IDs
Contiguous numbered IDs with a custom prefix, step, and zero-padding. Perfect for seeding test data, ticket numbers, SKUs, or CSV imports.
ID-0001 ID-0002 ID-0003 ID-0004 ID-0005 ID-0006 ID-0007 ID-0008 ID-0009 ID-0010 ID-0011 ID-0012 ID-0013 ID-0014 ID-0015 ID-0016 ID-0017 ID-0018 ID-0019 ID-0020
How to build a number sequence
Pick a start, a step, and a count — we render {prefix}{padded number} for each.
- 01
Set start & step
Start at any integer; step can be 1, 10, -5, anything.
Inputs are treated as UTF-8 throughout the pipeline and validated client-side as you type — nothing dispatches until the value is well-formed.
rangeinpututf-8client-sidevalidatedstart · text1 · set1, 2, 3, …
loaded · parsedclient-side - 02
Choose count
Up to 10,000 in a single batch.
Each toggle re-computes through a memoised hook, so flipping options never resets your input and the UI stays snappy on large inputs.
countoptionslivememoisedtogglescount · memoised20 · live20 IDs
options set · memoisedlive - 03
Add prefix
Anything before the number — "ID-", "SKU", "T_".
Randomness — where used — comes from
crypto.getRandomValues, neverMath.random. Heavy work sits inuseMemo.prefixcomputeinstantlocaldeterministicprefix · instantID- · computedID-0001
computed · instantinstant - 04
Zero-pad width
Slide to add leading zeros for sortable output.
Copy writes through
navigator.clipboardand downloads use aBlob— zero network traffic. Same input plus same options always yield the same bytes.padcopydownloadzero-networkreproducibleok · copied4 wide · copiedID-0042
shipped · ready to shipsuccess
Pro tips for everyday utilities
Reach for crypto.getRandomValues
Cryptographically random for IDs, tokens, salts. Math.random is for animation and games, not security.
Mock data with seeds
Faker-style libraries can be seeded so tests are reproducible. Embed the seed in the fixture file.
Reference cards beat memory
Cheatsheets for Vim, Git, Docker, Linux signals are faster than man pages when you’re mid-flow.
Browser APIs vary
Touch events, gamepads, and clipboard differ across vendors. Feature-detect before use.
Persist in the right place
localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data.
When to use sequential IDs
Test data, SKUs, tickets, invoices.
Seed test data
Predictable IDs across runs make assertions easier. Random values come from crypto.getRandomValues — cryptographically secure for tokens, salts, and session IDs. Math.random is deterministic enough for animations but predictable enough to be a security bug.
CSPRNG-backedSKU prefixes
Generate SKU lists by category prefix. Pair with hashids, ULID, or UUID v7 when you need both random and sortable — useful for primary keys, public-facing IDs, and event log ordering without a sequence column.
reproducibleTicket numbers
Support tickets, RMAs, conference badges. Output is deterministic given the same seed, so fixtures and tests stay reproducible across CI runs and contributor machines. Embed the seed in the fixture file for full replay.
snappyInvoice numbers
Sequential billing IDs with year prefix. Heavy work runs through useMemo so the UI stays snappy on large inputs. Same input + same options yields identical bytes — the kind of stability snapshot tests rely on.
feature-detectedOrder numbers
Friendly customer-facing order IDs. Storage tools persist to the right backend: localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data. Pick the right shelf and quota worries disappear.
deterministicMigration scripts
Generate FK targets for joined inserts. Browser feature detection: clipboard, fullscreen, gamepad, and Web Bluetooth APIs gracefully fall back when unavailable. No surprise white screens on Safari or older Firefox.
production-readyFrequently asked questions
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