Hallmark

Hallmark is an open-source design skill for AI coding agents, with around 31,500 stars on GitHub under the MIT license. It works with Claude Code, Codex, Cursor, and OpenCode, and it exists to solve one problem: web pages built by AI that all look the same.

Overview

Hallmark describes itself as a design skill that refuses to look AI-generated. It holds a hard quality floor and then gets out of the way: it deals three themes from a catalog of forty-eight materials, builds the page around what the visitor came to do, and lints the result in a real browser against the tells that read as machine-made. A fresh-context reviewer gets the last word before anything ships.

Key Features

• Forty-eight themes: Each theme is a material with its own components, texture, and a picture of a finished page. A theme never dictates content or order, so two prompts in one theme produce two different pages.
• Tiered quality gates: The Floor never ships, covering contrast, focus, reduced motion, invented facts, and broken phone layouts. Reflex gates catch the defaults models fall into, and Finish checks add craft detail without blocking a release.
• Real-browser linting: The sloplint script checks the page at eight widths and a subagent reviews it with fresh eyes, catching problems a static checklist would miss.
• Redesign and audit commands: Redesign rebuilds an existing page while keeping its content and wiring, failing if a single link, field, handler, or heading goes missing. Audit only reports problems.
• Built from the job: A booking page books, a shop sells, and a newsletter subscribes. The action sits where the category puts it, and the page ends on it.
• Custom mode: Ask for a custom page and Hallmark designs from the prompt alone, under the same rules and checks, finding one idea that only this client has.
• Real photographs: A library of 755 openly licensed photos, picked per subject and credited on the page, so builds never rely on invented imagery.

💳 Pricing

Hallmark is free and open source under the MIT license. There is no paid tier; anyone can use it, fork it, and ship with it.

Who Is It For

Hallmark is for developers and designers who build websites with AI coding agents and are tired of generic, obviously AI-made output. It suits anyone who wants distinctive, human-feeling pages without giving up the speed of AI-assisted building.