No API anywhere
There is no national vanity plate API, and no state publishes one. The only source of truth is each DMV’s public web form.
Overview
A simple question with no easy answer.
Is the vanity plate I want still free? To find out, you usually have to find your state’s DMV site, click through its own multi-step form and decode its wording. Most states don’t offer a checker at all.
PlatePing puts that behind one search box. Pick a state, type a plate, and get a clear answer. For four states it’s a live answer from the DMV itself. For the rest it’s a format check against that state’s rules.
The problem
Three reasons nobody had built this.
Every state is different
Each form has its own steps, fields, wording and technology, from old ASP.NET postbacks to AJAX fragments.
Bots aren’t welcome
Some DMV sites sit behind Akamai bot protection, and some vendors forbid automation in their terms.
Research
Four states, four different forms.
I mapped each state’s flow in the browser’s network tab before writing any automation.
New Hampshire
A wizard: vehicle type, then plate type, then the plate. The result is read from a status indicator and sorted into available, taken or not allowed.
Florida
An ASP.NET WebForms page. Submit triggers a full-page postback, so the check waits for navigation and then reads a status label.
Ohio
Choosing Passenger and clicking “Check Availability” fires an AJAX request that returns an HTML fragment with a success or danger alert.
Pennsylvania
Redirects across PennDOT hosts, three postback steps, and the plate typed into one input per character.
Design
One search box, an honest answer.
Fast path first
The four live states sit above the search as one-tap chips. Every other state is one dropdown away, so the fastest path is also the most useful one.
Show the plate, show the place
The answer comes with a preview of the plate itself and a US map that zooms into the chosen state. The map is built with react-simple-maps and d3-geo, fitting each state to the frame.
Clear result states
Live checks return Available, Taken or Not allowed. Format checks say Format check passed, never “available,” because PlatePing can’t know that for those states.
History and themes
A Recent checks page keeps the last 20 lookups in local storage, on the device only. The interface works in light and dark mode.
Build
A headless browser behind every live check.
Each live state has its own API route that opens Chrome, fills in the DMV’s form like a person would, and turns the page into a clean result.
Live checks
- Playwright drives each state’s public form. Every adapter documents the flow it relies on: URLs, selectors and the exact result wording.
- All adapters return the same shape: available, taken, not allowed or error. They never throw.
- A hard timeout (15 s locally, 25 s on Vercel) means a slow DMV can’t hang the app.
Running Chrome on Vercel
- On Vercel,
@sparticuz/chromium-mindownloads a Chromium build at cold start, kept out of the bundle. - Locally it prefers the system Chrome, because Akamai blocks stock Chromium on some DMV sites.
- An optional remote browser (a Browserless or Playwright endpoint) can take over for sites that block serverless IPs.
Guardrails
- Rate limit of 10 checks per minute per IP, so PlatePing is a polite visitor.
- Results are cached for 5 minutes, so repeat checks don’t hit the DMV again.
- Block pages (Akamai “Access denied” and similar) are detected and reported as errors, not as wrong answers.
Format rules
- Every other state gets a format check: length, allowed characters and at least one letter.
- New Hampshire uses its own rules: up to 7 characters, 1–9 (no zero), and up to 2 non-consecutive symbols (&, +, -).
- Plates are normalized before checking: spaces removed, uppercased, zero read as O.
One live check, start to finish
- RequestState and plate from the UI
- Rate limit10 per minute per IP
- Cache5-minute result cache
- Headless ChromeFills in the DMV’s public form
- ResultAvailable, taken, not allowed or error
Each live state has its own route (/api/check-nh, -fl, -oh, -pa) with the same steps. Errors are never cached.
Scope
Choosing what not to automate.
Only public tools
Live checks run only where a state publishes its own public availability tool. Most states don’t, so they get a format check instead of a guess.
Respecting terms
Texas has a checker, but its vendor’s terms forbid robots and scrapers. PlatePing keeps Texas to format checks and notes why in the code.
Built to break gracefully
These are unofficial integrations. If a DMV redesigns its page, the check returns a clear error instead of a wrong answer until the adapter is updated.
Results
Live, working and honest about its limits.
PlatePing is live on Vercel, and live checks return real answers from the DMVs in production.
- Live DMV integrations
- 4
- States with format checks
- 50 + DC
- Repeat checks cached
- 5 min
- Launched in September 2026 at plateping-eight.vercel.app, with the source public on GitHub.
- Live checks for New Hampshire, Florida, Ohio and Pennsylvania, each through that state’s own public tool.
- Format checks for every other state and DC, clearly labeled as format checks.
What I learned
Three things I’d carry into any project.
Read the network tab first
Mapping each form’s requests and responses before writing code made the adapters short and the edge cases predictable.
Design for the unhappy path
Timeouts, bot walls and redesigned pages are normal here. Typed results that never throw kept the UI simple.
Honesty is a feature
Saying “format check passed” instead of “available” is less impressive, but it’s the only answer users can trust.
What’s next
Where PlatePing goes from here.
- Move the rate limit and cache to a shared store, so they hold across serverless instances
- Scheduled smoke checks that flag when a DMV changes its page
- More live states, wherever a public tool exists and its terms allow it
Keep exploring
More from this work.
Have a project in mind?
Tell me what you’re building. If I’m not the right fit, I’ll tell you that too.
or email hi@klep.dev