Keycheck audits env vars in browser

Keycheck, an open-source web utility, compares local .env files against a project template without transmitting any data to a server [DevTo]. It accepts either pasted text or uploaded files, parses both the local environment and the template, and highlights missing, stale, empty, or placeholder variables. For each missing key, it generates a ready-to-paste snippet, letting developers fix the configuration in seconds. The entire parsing and diff logic runs in the browser, so no backend service is required [DevTo]. The source code is MIT-licensed, hosted publicly, and includes a contribution guide, code-of-conduct, and simple build instructions that spin up a local development server with a single npm command. Keycheck's client-side approach keeps secrets on the machine, eliminating the attack surface introduced by cloud-based linting services [DevTo]. By integrating Keycheck into existing CI pipelines as a simple npm script, teams can enforce config hygiene without extra infrastructure, satisfying compliance requirements for regulated industries.