SeatCheck
LiveWhat child car seat does the law actually require, in every US state
Built by Caden Sorenson · Launched June 2026
What is SeatCheck?
SeatCheck answers one question, for every US state, with a citation: what child car seat, booster, or restraint does the law require? It exists because the honest answer is genuinely hard to find. The rules change at every state line, the official statutes are often buried or locked behind clunky portals, and most of what ranks online is ad-choked guesswork that blurs “the law” with “what a pediatrician recommends.”
It covers 56 jurisdictions: 50 states, DC, and five territories. For each one it shows the legal requirement and, separately, the American Academy of Pediatrics best-practice recommendation, so the two are never mistaken for each other.
How it works
You pick a state and enter your child’s age, height, and weight. SeatCheck returns the restraint the law requires there, rear-facing car seat, car seat or booster, or seat belt, and cites the exact statute. The same checker is published as an embeddable widget any site can iframe in.
Key Features
- All 56 US jurisdictions, each statute-sourced with its own last-verified date and source tier
- 84 state-vs-state comparison pages generated by a deterministic engine, so two pages differ exactly as much as the underlying law differs
- Law and recommendation kept separate, with the legal requirement as the floor and AAP guidance shown as best practice, never as a requirement
- Embeddable widget: no cookies, no accounts, self-contained CSS and JS, themeable by the host site and deep-linkable by URL parameters
- Provenance tooling: three lint scripts catch unsourced facts, internal contradictions, and dead source links so the data does not silently rot
Why it is built this way
SeatCheck is YMYL (you-your-money-or-your-life) child-safety content, which is why accuracy and provenance are prioritized over speed. Every threshold traces to the official statute, a statute that is silent on a value is recorded as null rather than filled with a reasonable guess, and the AAP recommendation is stored and displayed as a separate field so it can never be presented as law. A wrong car seat age is not a cosmetic bug, so the whole system is built to make a wrong number hard to ship.
Frequently asked questions
What does SeatCheck tell a parent?
Which states does it cover, and how accurate is the data?
Can I add the car seat checker to my own site?
Is SeatCheck legal advice?
More about SeatCheck
- Behind the build Building SeatCheck: A Car Seat Law Site Where a Wrong Number Could Hurt a Kid My kid wanted a booster seat and the answers online about the law were terrible. So Claude and I built a cited car seat law site for all 56 US jurisdictions.
- From the blog Building Travel Vient: The Real Work Was Not Trusting Claude How I built travelvient.com, a travel site with data on 80 airlines, by letting Claude generate under skills I wrote and catching it when it makes a fact up.
- From the blog Building a Single-Page Client Site, Mostly by Prompting Claude A local client had an Instagram and no website. I gave Claude the prompt, the real details, and a style direction, and it built three files. Content was harder.
- From the blog Building a Local-SEO Site for an Age-Restricted Shop, in Code This Time After rebuilding one AI-builder client site in code, I built this one in Astro with Claude from day one: a clean local-SEO site for an age-restricted retailer.
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