License plate generator from a pattern and seed

Choose a supported arrangement such as three letters followed by three digits, then provide any stable seed that identifies your test case. The same template and seed always return the same result, which makes the tool useful for fixtures, mockups, demos, and repeatable sample data without copying a real vehicle registration accidentally.

Choose a layout that matches your mock data

Start by selecting one of the recognized templates. Each template defines the number and order of letter and digit groups, while hyphens make the result easy to read. For example, the three-letters-three-digits template produces a value shaped like ABC-123, and the one-letter-three-digits-two-letters template produces a value shaped like A-123-BC. The generator intentionally supports a documented set rather than trying to interpret arbitrary prose. That strict boundary prevents a misspelled template from silently producing a plate with the wrong shape. It also makes validation straightforward in automated tests because every accepted format has a stable contract. The letters come from an ambiguity-reduced uppercase alphabet that omits characters commonly confused on signs and small images. Digits use the standard zero-through-nine set. The result is plausible display data, not a claim that the format is officially issued by a particular authority. Always choose the layout your interface, fixture, or demonstration expects, and treat jurisdiction-specific legal rules as a separate concern.

Use the seed as a repeatable identity

The seed controls which characters fill the selected layout. It can be a fixture name, an internal example label, a vehicle reference used only in a test environment, or any other stable text. The algorithm combines the complete seed with the chosen template and each output position, then maps the resulting unsigned value into the appropriate letter or digit alphabet. No random source, current time, network call, stored counter, or process state participates. Consequently, identical inputs produce identical JSON across repeated runs, while a different seed normally produces a different plate. The template is part of the derivation as well, so changing the layout creates a fresh result instead of merely rearranging characters from the old one. Seeds are treated as exact, case-sensitive strings: Demo, demo, and demo followed by a space are distinct inputs. Keep that behavior in mind when generating fixtures from user data. Normalize a seed in your own application first if capitalization or surrounding whitespace should not distinguish records. The response echoes both inputs alongside the generated plate so logs and snapshots remain understandable.

Apply generated plates responsibly

Generated plate-style strings are most useful where realistic shape matters but a real registration must not be exposed. A design team can populate vehicle cards, a developer can create stable end-to-end fixtures, and a documentation writer can show an API response that remains unchanged between builds. Because the output only follows a visual template, it does not check registration databases, reserved sequences, regional prefixes, checksum rules, diplomatic ranges, or whether an authority could issue the value. A generated string may coincide with a real plate by chance, so do not use it to identify, accuse, impersonate, register, or authorize a vehicle. For public mockups, consider adding an obvious fictional context around the plate as well. Automation clients receive the same deterministic result as the browser tool. A malformed or unsupported pattern returns an invalid-input error instead of guessing, which lets pipelines fail early and makes template migrations deliberate. Browser use is free, while an API request uses the displayed $0.002 base price. Store the seed when you need to reproduce a value later; no server-side history is required for regeneration.