Source: https://mokxi.com/learn/fix-arduino-code-with-ai Updated: 2026-11-10 Learn # Fix Arduino code with AI, and see it compile before you accept it Beginner Written by the Mokxi team, updated November 10, 2026 Start building free Open the editor Or see every lesson. - 505 parts on the bench - 45 boards running now - 1.00x real time, on every board Hold the button Break a line, press Run, then ask Mokxi AI to explain the error or fix it. Paste a broken sketch into a chatbot and you get back code that looks right. Whether it builds is your job to find out, and often it does not: a function that library does not have, a pin the board does not have, a missing brace. Mokxi AI, the helper in the Mokxi editor, checks that part for you. Its fix is compiled in your browser, with the same compiler Run uses, before the Accept button appears. The circuit above is a button and an LED on an Uno. Open it in the editor, delete the semicolon after pinMode(BUTTON_PIN, INPUT_PULLUP) and press Run. The build stops. Ask Mokxi AI "Why won’t this compile?" for the explanation, or press Fix it for the change. Below is how Fix it works from the error to Accept, what Mokxi AI sees when it fixes, and what a fix that compiles still does not prove. ## From the error to Accept A Run that fails shows the compiler’s errors in the build tab, and Mokxi AI offers two buttons: "Why won’t this compile?" and "Fix it". The first explains the error in plain words, with the line it is on. The second asks for the change itself. Mokxi AI answers Fix it with edits, each one an exact piece of your file and what goes in its place. Mokxi applies them to a copy, never to your file, shows you the lines that change, and compiles the copy. While it builds the card says so; when it builds, the card says "Compiles" and Accept appears. Accept puts the change into the editor as one edit, so Ctrl+Z takes it back. Not now leaves your code alone. If the copy does not compile, Mokxi AI gets the compiler’s error and one more try, which does not cost you a question. A fix that still does not build is not offered. ## Why compiling first matters Most wrong AI answers about Arduino code fail at the first step: they call a function the installed library spells differently, use a name the board’s core does not have, or close a brace that was never open. Each of those is caught by compiling, in seconds, before you read a line of it. The fix you see has already passed the check you would otherwise run yourself. It also means the fix is for your board. A sketch for an ESP32 is compiled for the ESP32 and a sketch for an Uno for the Uno, with the libraries your project uses. ## What Mokxi AI sees when it fixes Your whole project, not just the line with the error: every tab, the board, the parts and the wires on the canvas, and the build’s errors. A question about why an LED stays dark can be answered from the wiring as well as the code, which a pasted snippet never shows. "What is sent" in the panel shows the project text exactly as Mokxi AI got it, and nothing about you goes with it. ## Compiles is not the same as works A fix that builds can still be wrong: the right syntax with the wrong pin, a delay that is too short, a sensor read in the wrong units. That is what the simulator under the editor is for. Accept, press Run, and watch the LED, the serial monitor or the scope. If it still misbehaves, tell Mokxi AI what you saw; it can read the circuit you are both looking at. Read the change before you accept it, too. The card shows every line that changes, and a fix you understand is one you will not need to ask about again. ## The errors worth asking about The errors that stop the most Mokxi builds are the plain ones: a missing semicolon or bracket, a name the compiler has never heard of because of a typo or a capital letter, a library header that is not included, and a sketch with no setup() or loop(). The build tab explains most of those itself, and each has a guide on this site with every cause and fix. Start there; it costs nothing. Mokxi AI earns its place on the rest: an error deep inside a library, a message that runs to twenty lines of notes, three errors where fixing the first should fix the others, or a sketch pasted from a tutorial written for another board. Those are the ones where reading your whole project, and building the answer before showing it, saves the most time. ## How many fixes Each Fix it is one question from the day’s allowance, signed in: 5 on a free account, 50 on the Pro trial and 100 on the paid plans. The second try after a fix that did not compile is free, and a question that fails before any answer is handed back. Open this circuit in the editor. Arduino Uno: a sketch to break, and let Mokxi AI fix, wired as it runs at the top of this page. Change a part or a value and run it again. Open the circuit ## Questions Can AI fix my Arduino code? Often, for build errors. In Mokxi, Mokxi AI proposes the change and the editor compiles it before you can accept it, so a fix that does not build is never offered. Is there an Arduino code checker with AI? Mokxi compiles your sketch with a real compiler when you press Run, explains the common errors in the build tab, and Mokxi AI explains the rest and proposes fixes that are compiled first. Will Mokxi AI change my code without asking? No. Its edits go to a copy. Only Accept puts them into your file, as one edit you can undo. Does a fix that compiles mean my sketch works? No. It means it builds. Run it in the simulator and watch what the circuit does to know whether it works. Related ## Keep going Arduino Compile Errors Explained, With the Fixes How to Debug Arduino Code: Prints to Breakpoints Arduino "exit status 1": Find the Real Error "Was Not Declared in This Scope" in Arduino: 6 Fixes Arduino "expected ';' before" and Similar Errors Arduino AI Assistant in Your Browser: Meet Mokxi AI The online Arduino compiler Open the editor The project page, with the full sketch Beginner Sources ## Where the facts on this page come from - Arduino language reference ## Build this for real Open the editor, change a value and watch the number move with it. Nothing to install, and no account needed. Start building free Open the editor