TRMNL Dev

Field-tested knowledge for building and operating TRMNL private plugins: what the docs say, plus the gotchas the docs don't mention (rendering geometry that clips, MCP quirks, CSS cascade layers, payload byte limits).

Mental model

TRMNL is server-rendered e-ink. The device polls; nothing is pushed to it.

data source ──► webhook POST ──► merge variables ─┐
                                                  ├─► TRMNL renders PNG ──► device wakes,
markup editor / MCP ──► Liquid template ──────────┘    downloads image, sleeps

There are two independent update paths — never confuse them: