Diagnost vs Carly: a free Carly alternative that works with any adapter

Most people searching for a Carly alternative have already seen the two conditions attached to the app: a yearly license tied to a car brand, and a branded Bluetooth scanner you must buy because nothing else works with it. This page compares Carly with Diagnost, a free Windows program, using only what each vendor publishes, as of September 2026. No review-quoting, no editorializing — just what the tools do.

What each one is

Carly is a mobile app for iOS and Android paired with the Carly Universal Scanner, a compact Bluetooth dongle. The vendor states plainly that the app is developed for its own scanner and that third-party adapters do not produce sufficient results. Generic OBD-II work — reading and clearing engine codes, emission readiness, some live parameters — is free in the app. Everything else, meaning all-module diagnostics, coding, service functions and the used-car check, sits behind a paid license that runs for a year and is bought per car brand, with a separate all-brands upgrade. Official site: mycarly.com.

Diagnost is a free program for Windows 7 through 11, with macOS listed for USB and WiFi adapters. It scans for every adapter you have connected — USB, Bluetooth, BLE, WiFi, J2534, cables — and picks the one that is actually plugged into the car. It reads every module it can reach: engine, transmission, ABS and stability control, airbags, body, instrument cluster, climate. It has a built-in AI mechanic that queries modules on its own and explains findings in plain language. On BMW it goes deeper: E chassis and Mini R50-R56 over K+DCAN, F, G and I chassis over ENET.

Side by side

Where Carly is genuinely better

It is in your pocket. A phone and a dongle the size of a matchbox beat a laptop on a stranger's driveway, at a pre-purchase inspection, or when a light comes on 200 miles from home. Pretending otherwise would be dishonest.

VAG coding. Diagnost codes nothing but BMW and Mini. If your goal is to unlock hidden options on an Audi, VW, Skoda or SEAT, Diagnost will not do it, and that is a design decision rather than a missing release.

BMW F and G coding comfort. Carly's option library is broader and friendlier for someone who just wants to kill the seatbelt chime and enable folding mirrors from a phone. Diagnost also codes with checkboxes, but its option list on newer chassis is narrower.

A single used-car report. Carly bundles the all-module fault scan and the cross-module mileage comparison into one guided flow. Diagnost exposes the same data, but as separate screens, and its mileage cross-check is BMW-only.

Where Diagnost is better

Any adapter, including the one you already own. Diagnost identifies an ELM327 from its reply to ATZ and ATI, drives OBDLink units on STN chips — including MS-CAN for Ford and Mazda, and SW-CAN for GM and Opel on the MX+ — and takes J2534 devices such as Mini-VCI, Tactrix Openport, Scanmatik or VXDIAG as a virtual ELM327 through the PassThru API. You can leave several adapters connected at once; it picks the live one and survives unplug-and-replug without a restart. J2534 support arrived in version 3.1.12 and the GM single-wire module in 3.1.13; both are still being verified on real hardware.

No license at all. Not a limited free tier — the whole program: all-module scanning, per-module or full clearing, freeze frames, emission readiness monitors, live sensors, graphs, module backups, session history by VIN, and the AI mechanic. Hardware is the only cost: about $10 for K+DCAN or ENET, about $5 for a VAG KKL cable, less for a plain ELM327.

A real screen and real time. A dozen live parameters at once instead of two. Record a drive, then scrub the graphs afterwards. Keep session history per VIN and diff the fault list against the previous visit — the kind of work that is physically awkward on a phone.

The AI mechanic. It does not just print a code definition; it decides which additional modules to query and explains the likely cause in plain words. Carly has no equivalent.

Toyota hybrid battery test. Diagnost reads the voltage of every block in the high-voltage pack, calculates the spread and gives a verdict — Prius 2, 3 and 4, Aqua, Auris HSD, CT200h, Camry Hybrid, RX400h and RX450h. For anyone buying a used hybrid, that single test is the reason mobile inspectors get paid.

Carly for PC: the honest answer

There is no Carly desktop application as of September 2026. Carly is a phone app, full stop, and no emulator trick makes a Bluetooth dongle behave properly under one. If what you actually want is the Carly feature set on a computer, the substitution is not "Carly for PC" but a different program plus an adapter you can buy anywhere: Diagnost with a $10 cable or an inexpensive Bluetooth ELM327 covers reading, clearing, live data and, on BMW, coding and service functions. For a two-minute check with nothing installed, the browser page at /connect reads engine codes straight from Chrome or Edge over USB or BLE.

Which one to pick

Choose Carly if you drive a VAG car and want option coding, if you have no laptop and no intention of using one, or if quick roadside checks are the whole use case and the yearly fee does not bother you.

Choose Diagnost if you already own an adapter and refuse to buy a second one for a specific app, if paying every year for something you use twice a year makes no sense, if your car is not German — a generic ELM327 gets Diagnost into every module on any CAN car — or if you own a BMW and want dealer depth, in which case start with the BMW program page and the BMW diagnostics section.

Running both

They coexist cleanly. Different adapters, different devices, different jobs: the phone for the road and for inspecting someone else's car, the laptop for the hour you spend chasing an intermittent fault, pulling history by VIN, or letting the AI mechanic work through the module list. The only rule is not to connect two programs to the car at the same time — one bus, one adapter, mixed replies.

If you are shopping tools for a BMW specifically, compare also with BimmerCode and BimmerLink, with INPA and with ISTA — those are dealer-side tools and the trade-offs are different.