The Spark: A Private Message

In April 2026, developer Paweł Jarczak received an unexpected private message on Reddit from Bambu Lab, a company widely regarded as the Apple of 3D printers. The message politely asked Jarczak to remove code he had published that allowed remote control of Bambu printers without using Bambu’s official software. Bambu warned that upcoming changes could break his work, but the tone was civil. Jarczak initially agreed to remove his GitHub project, but asked for acknowledgment and even requested a free printer as recognition for exposing a security gap. That request changed everything.

Escalating Threats

Bambu’s response shifted dramatically. The company told Jarczak that a cease and desist letter had been prepared and referenced Section 1201 of the DMCA, implying legal action for bypassing digital locks. However, Bambu never filed a lawsuit, sent a proper DMCA takedown, or issued a formal cease and desist. Jarczak voluntarily removed his code but replaced it with a note suggesting he had been treated like a criminal. That note ignited a firestorm.

Community Backlash

The open-source 3D printing community quickly rallied behind Jarczak. Consumer rights advocate Louis Rossmann pledged $10,000 to defend him in court. Maker Jeff Geerling announced he would never buy another Bambu printer and offered to chip in. Most strikingly, the PC hardware outlet GamersNexus publicly told Bambu to “Go fuck yourself” and pledged $10,000, while also halting previously unannounced plans to spend $150,000 on Bambu hardware. The Software Freedom Conservancy, led by Bradley Kühn—the creator of the AGPL license—began hosting a project to reverse engineer Bambu’s code and vowed to act as a watchdog.

Why the AGPL License Matters

At the heart of the dispute lies the AGPLv3 license. Bambu Studio, the company’s flagship slicer software, is built on open-source code: it is a fork of PrusaSlicer, which itself is based on Slic3r from the RepRap community. The AGPL requires that anyone distributing modified versions must also release the full source code, including any “Corresponding Source” that is intimately connected. Bambu added a proprietary networking plug-in that communicates closely with the open-source parts, yet kept it closed. Jarczak’s fork worked around this by using code from Bambu’s own Linux version, effectively picking the lock with Bambu’s own key.

Kühn argues that Bambu is in clear violation of two AGPL obligations: first, by not releasing the networking plug-in’s source, and second, by pressuring Jarczak to remove his code while falsely claiming terms of service trump license rights. Jarczak published a 30-point analysis demonstrating the intimate communication between the plug-in and the open-source code. But legal experts are divided. Two open-source attorneys told this publication that the AGPL’s scope is ambiguous, especially regarding cloud services and plug-ins. Kyle Mitchell, an independent tech lawyer, notes that the license was written to address web services but does not clearly force companies to share all cloud-side code. Heather Meeker, a prominent licensing attorney, agrees that plug-ins generally fall under “Corresponding Source” but acknowledges that courts have not meaningfully interpreted the AGPL.

Bambu’s Defense: Security and Separation

Bambu argues that its networking plug-in is “separately delivered” and therefore not covered by the AGPL. The company also claims that Jarczak’s fork “impersonated” its systems, posing a security risk and enabling DDoS attacks. Bambu provided a screenshot showing Jarczak’s code identifying itself as “BambuStudio”—a label that appears in Bambu’s own open-source code. Jarczak counters that any security issues are server-side: proper authorization, token scopes, and rate limiting should handle abuse. He insists he never attacked Bambu’s infrastructure, merely tested his own normal workflow. Bambu declined to share its logs with the publication.

The Standoff Intensifies

In the weeks since, the conflict has escalated beyond Jarczak. The Software Freedom Conservancy launched a fundraising campaign to “liberate AGPLv3-violating 3D printers,” aiming for $250,000. Rossmann’s group pledged $15,000. Thousands of developers have forked Bambu’s code, daring the company to take legal action. Bambu initially took a hard line, stating it would “hold a firm line on how our cloud service is accessed by third-parties.” But a day later, the tone softened: “Rather than escalating conflict, we are focusing on strengthening our own infrastructure.” The company has not yet filed any lawsuits, leaving the battle in the court of public opinion.

What’s at Stake for 3D Printing

The outcome of this dispute could reshape the entire 3D printing industry. Bambu’s printers are beloved for their ease of use, but the company’s approach to software echoes the printer industry’s move toward lock-in—potential subscriptions, proprietary filaments, and walled gardens. If Bambu prevails, other manufacturers may follow, eroding the open-source foundations that made desktop 3D printing accessible. If the community wins, it may set a precedent enforcing AGPL compliance, forcing companies to fully open their software or rewrite it from scratch. Kühn suggests Bambu should simply release all code, as its business is hardware anyway. But Jarczak warns that a fully closed system would be “more honest” than the current gray area.

For now, nothing is resolved. The developer who started it all says he is no hero, just someone who wanted to keep using third-party multicolor systems with his printer. But his private DM has become a flashpoint for a generation of makers, lawyers, and engineers who believe the software that runs their machines should be as open as the hardware itself.

Source: The Verge News