--- title: "Bambu Lab Developer Mode: Why Controls Are Locked ยท Bambu Bar" description: "Why pause, resume, stop and speed are locked in third-party apps, what Bambu Lab's Developer Mode changes, and how to turn it on for Bambu Bar." url: https://bambubar.app/guides/bambu-lab-developer-mode language: en --- # Why controls are locked. And Developer Mode Bambu Lab printers accept print commands from third-party apps only in LAN Only mode with Developer Mode on. Here's what that means, and whether it's worth turning on. _Updated 2026-11-03_ ## In short Bambu Lab printers only accept **pause, resume, stop and speed** commands from third-party apps when the printer is in **LAN Only** mode with **Developer Mode** on. Until then, Bambu Bar shows a lock on those buttons and tells you why. Reading status works in any mode, and the chamber light works either way. If you only want to watch prints, you don't need Developer Mode. ## What's locked, and what isn't | In Bambu Bar | Cloud mode | LAN Only | LAN Only + Developer Mode | | --- | --- | --- | --- | | Progress, temperatures, AMS, errors | Yes | Yes | Yes | | Chamber light | Yes | Yes | Yes | | Pause, resume, stop | Locked | Locked | Yes | | Print speed | Locked | Locked | Yes | The lock is the printer's rule, not Bambu Bar's: the printer refuses these commands from apps other than Bambu Lab's own unless Developer Mode is on. Bambu Bar shows the lock and the reason, instead of buttons that silently do nothing. ## What Developer Mode does Bambu Lab describes Developer Mode as an option for advanced users that opens the printer's MQTT channel, live stream and FTP, "giving you full control over your printer and its network security". It's only available in **LAN Only** mode. In practice: - Apps on your network that have the printer's **access code** can send it commands. - The printer stays in LAN Only, so **Bambu Handy, remote printing and print history aren't available**. See [LAN mode explained](https://bambubar.app/guides/bambu-lab-lan-mode). - You're responsible for your network's security: keep the access code private, and don't expose the printer to the internet. ## Turn it on Following Bambu Lab's [Developer Mode guide](https://wiki.bambulab.com/en/knowledge-sharing/enable-developer-mode): 1. Turn on **LAN Only** on the printer's screen (**Settings โ†’ LAN Only** on X1, H2 and P2S; **Settings โ†’ WLAN** on P1; **Settings โ†’ LAN Only Mode** on the A series). 2. On the same page, turn on **Developer Mode**. 3. Read the notice, confirm it, and enable it. The switch turns green, or shows ON. 4. If Bambu Bar was already connected, it unlocks the controls once the printer reports the new mode. To undo it, turn Developer Mode off, then LAN Only off to return to cloud mode. ## Should you turn it on? - **You only watch prints:** no. Status, the AMS, errors, notifications, widgets and the camera work without it. - **You want to pause or stop from your Mac:** yes, if you're happy to give up Bambu Handy and cloud features while it's on. - **You need Bambu Handy away from home:** keep cloud mode, and pause or stop from Handy or the printer's screen. ## How Bambu Bar sends commands Bambu Bar sends commands the same way it reads status: directly to the printer over an encrypted connection on your network, signed in with the access code, after checking the printer's certificate. Stop asks you to confirm first. See [how local monitoring works](https://bambubar.app/guides/bambu-lab-mqtt). ## Questions, answered ### Why can't I pause or stop a print in Bambu Bar? The printer is not in LAN Only mode with Developer Mode on. Bambu Lab printers refuse pause, resume, stop and speed commands from third-party apps otherwise. Bambu Bar shows a lock and the reason. ### Does Developer Mode affect print quality? No. It changes which apps the printer accepts commands from, not how it prints. ### Can I use Bambu Handy with Developer Mode on? No. Developer Mode needs LAN Only mode, and Bambu Handy isn't available in LAN Only mode. ### Does the chamber light need Developer Mode? No. Bambu Bar's chamber light switch works in any mode. ## Read next - [LAN mode explained](https://bambubar.app/guides/bambu-lab-lan-mode): Cloud mode, LAN Only, LAN Only Liveview and Developer Mode: four different settings, and which ones you actually need. - [How local monitoring works (MQTT)](https://bambubar.app/guides/bambu-lab-mqtt): The local MQTT connection behind Bambu Studio and Bambu Bar: port, topics, sign-in, certificates, and what's read versus sent. - [Support: Setup, Camera and Connection Help](https://bambubar.app/support): Set up Bambu Bar and fix printer discovery, camera, controls and widget problems, or get help with your supporter license and purchase account. - [Compatible Bambu Lab Printers: All 15 Models](https://bambubar.app/printers): Bambu Bar works with all 15 Bambu Lab printers: P2S, P1S, P1P, X1 Carbon, X1, X1E, X2D, A1, A1 mini, A2L, H2D, H2D Pro, H2C, H2S, H3C. Compare camera setup, chamber data and AMS filament for yours. --- Bambu Bar is an independent app, not affiliated with or endorsed by Bambu Lab. Bambu Lab is a trademark of its owner.