Command line

Hellbox ships with a command line interface for rendering proofs without opening the app. Point it at font files and get a finished PDF, or automate exports and render checks on saved .fontproof documents.

Setup

The CLI lives inside the app bundle. Add an alias to your shell profile:

alias hellbox="/Applications/Hellbox.app/Contents/MacOS/Hellbox"

Proof from Font Files

hellbox --proof renders a template-based proof straight from font files:

hellbox --proof MyFont.otf MyFont-Italic.otf proof.pdf

Pass one or more fonts followed by the output PDF path. Only compiled fonts are supported (.otf, .ttf, .ttc, .otc). Requires an active license or trial.

Flags:

  • --template "Name": which proof template to use. Default is “Pangram Proof”. Run --list-templates to print the available names.
  • --separate: write one PDF per font instead of one combined proof.
  • --instances "Bold,Black Italic": choose variable-font named instances. Default is all named instances.
  • --save-doc: also write the .fontproof document next to the PDF, so you can open it in Hellbox and refine it.
hellbox --proof renders a variable font’s named instances straight to a finished PDF hellbox --proof renders a variable font’s named instances straight to a finished PDF

Document Commands

These work on saved .fontproof files and have no license gate:

  • hellbox --export in.fontproof out.pdf: export a saved document to PDF.
  • hellbox --render-check in.fontproof: print JSON diagnostics, page count, page dimensions, character-coverage issues, and overflow issues.
  • hellbox --render-pngs in.fontproof outDir [scale]: render each page to a PNG in outDir. Default scale is 2x.

Recipes

Proof every font in a folder, one PDF each:

hellbox --proof Fonts/*.otf proofs.pdf --separate

Regenerate a proof after each export from your editor, re-run the same command whenever your font editor writes a new binary:

hellbox --proof build/MyFont-VF.ttf proof.pdf --template "Pangram Proof"

CI-friendly render checks, fail a pipeline on coverage or overflow issues by inspecting the JSON:

hellbox --render-check proofs/brand.fontproof

For AI-assistant workflows, see the MCP server page. The CLI covers terminal and scripting workflows; MCP lets tools like Claude create and modify proofs conversationally.