AT Command Tester online: talk to GSM/LTE modems from your browser

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Third tool in the browser-tools series: an AT command tester for cellular modems and IoT modules (SIMCOM, Quectel, u-blox and friends):

https://www.clearevo.com/at/

The old workflow for poking a GSM module was a generic serial terminal plus a datasheet, or one of the desktop AT-tester apps - the best-known one was Java-based and is painful to run on a modern machine. This one is just a web page: connect the module’s serial port (Chrome/Edge desktop, Web Serial API) and you get:

• a console with a click-to-send catalog of the common commands (identity, SIM, signal, registration, operator, APN, SMS mode…), each with a one-line description
• a script runner: paste a list of commands and it sends them one by one, waiting for OK/ERROR per command - handy for repeatable module bring-up checks
• a parsed status panel: AT+CSQ becomes signal bars with dBm, AT+COPS? shows operator and access technology, AT+CREG?/+CGREG?/+CEREG? show registration state in plain words

As with the other tools, everything is client-side - nothing you send or receive leaves your machine (Google Analytics for visit stats only). And there’s a clearly-marked DEMO simulated modem with canned responses, so you can try the whole thing without hardware in any browser.

Step-by-step user guide: How to test AT commands on a GSM/LTE modem from your browser.

Please test it against real modules and comment below - especially if your module needs commands or URCs the tool doesn’t handle well yet. That’s exactly the feedback I want.

Full disclosure: this post - and any code or tool it describes - was co-authored with Claude (Anthropic’s AI, via Claude Code). I directed, guided and reviewed. I don’t want to pretend otherwise.