Formlabs Updates PreFormServer API Documentation for PreForm 3.57.0 Release

Formlabs updated its Local API and PreFormServer documentation on March 18, 2026, syncing the published reference material to match PreForm release 3.57.0. For anyone running automated resin print workflows through the PreFormServer executable, that alignment matters: the material and settings list exposed by the API is static and will not change for a given version of the PreFormServer executable, which means documentation that lags behind the software release can quietly break integrations.

All Local API integrations involve starting the PreFormServer background application to expose its HTTP API, then making local HTTP API calls in your own code. The application functions like PreForm, Formlabs' regular job preparation application, but it does not open a graphical window and interaction is done entirely via HTTP API requests. The PreFormServer application is supported on both Windows and macOS, with separate downloads for each operating system.

The March 18 documentation note is the most recent in a series of incremental updates Formlabs has pushed to keep its developer resources current. The previous benchmark in the support documentation was Local API version 0.9.8, which recorded an update for PreForm release 3.53.0 and included a targeted fix: a bug where Auto Support did not work with mini raft settings. That fix was a practical one for anyone using automated support generation on smaller builds, where mini raft configurations are common.

The broader release history shows how quickly Formlabs has iterated on the Local API since its launch. Version 0.8.3 of the Formlabs Local API was released in November 2024, with changelog additions including async support for the print upload endpoint, new endpoints to poll for progress of long running operations, and support for Print Settings Editor .fps files when creating or updating a scene. Versions 0.8.1, 0.8.2, and 0.8.5 all followed in the same late-2024 window, with the developer forum tracking each release in the dedicated Developers category.

Community interest in PreForm versioning broadly remains high: the "PreForm older versions" general discussion thread on the Formlabs forum had logged 48 replies and 19,538 views as of its most recent activity on March 9, 2026, underscoring how closely the resin printing community monitors compatibility between software and hardware.

The API was created so users can integrate, automate, and customize their use of Formlabs products in ways specific to their use case, and keeping the documentation version-locked to each PreForm release is what makes that automation reliable. With 3.57.0 now reflected in the official PreFormServer documentation, developers building or maintaining print automation pipelines against Formlabs hardware have a confirmed, current reference to work from.