About Koydo CDL

Who Koydo CDL is for

You, if you're getting your first CDL, adding an endorsement like HazMat or Air Brakes, or coming back after time off the road. Whether you test in Texas, California, Florida, or any other state, the goal is the same: turn the 200+ things you have to know into a study plan that actually sticks, and a mock exam that tells you when you're ready.

Studying in Spanish? Koydo CDL is fully bilingual — every section, every state guide, in español.

What you get

• State-specific practice for all 50 states plus DC — your test is run by your state DMV, so your prep should match it.
• Every CDL section — General Knowledge, Air Brakes, Combination, HazMat, Tanker, Doubles/Triples, Passenger, School Bus, and Pre-Trip.
• An AI tutor that explains why an answer was wrong, not just what the right one was — and adapts to how close your test date is.
• Parked-study audio for every section, so you can review on a break instead of staring at a screen. (Never while driving.)
• A timed mock exambuilt to the real 80% passing bar, so you know when you're ready for the DMV.

How we build the questions

Every question and explanation is written and reviewed by the Koydo Lyceum — our editorial team — and checked against the official material the real test is built on: the FMCSArules, the federal CDL standards in 49 CFR Part 383, and each state's own DMV manual. When a state changes a fee, an age rule, or a CLP wait time, we update the guide for that state.

We show our work. Every number and rule traces back to a named, official source on our sources & methodology page. If something on Koydo CDL ever disagrees with your state DMV, the DMV is right — tell us and we'll fix it.

Independent — and honest about it

Koydo CDL is an independent study aid. We are not affiliated with, endorsed by, or operated by the FMCSA, any state DMV, or any official testing authority. All trademarks belong to their respective owners. Always confirm the current requirements for your license with your state DMV before you test.

Reach a human

Questions, a wrong answer to report, or a state rule that changed? Email support@koydo.app and a real person on the Koydo team will get back to you. You can also visit our support page.