A run reads every registry your packages live on (npm, PyPI, Docker Hub, GitHub, GitLab), appends the readings to a plain file, and rewrites one static HTML page. No account, no database, nothing to keep running. The timer is yours.

npm install -g terz-cli

mkdir adoption && cd adoption
terz init          # writes terz.config.json
terz run           # takes a run, writes chart.html and terz.json

List your packages once, in terz.config.json:

{
  "name": "Acme",
  "products": [
    {
      "name": "Acme CLI",
      "slug": "acme-cli",
      "sources": { "npm": ["acme-cli"], "pypi": ["acme-cli"] }
    }
  ]
}

Then give the run to a timer. Once a day is right: the download APIs refresh daily, and reading them more often only spends rate limit.

0 8 * * *  cd /path/to/adoption && terz run

What a run leaves behind

chart.html · the chart, one self-contained file. Serve it, or open it off disk.
terz.json · the same chart as a document, for the Terz apps and anything else that wants the numbers. Schema: https://terz.dev.
readings.jsonl · every reading ever taken, one JSON object per line. Append-only; your history is a file you can read with tail and back up with cp.

A source that does not answer is held, not fatal: the chart keeps the last good value, dimmed, with a tag saying how long it has been held. A missing reading is never rendered as a zero; zero is a real measurement.

Revenue, optionally

Adoption and money on one page. Set a restricted, read-only Stripe key in the environment under STRIPE_KEY_<SLUG> and give the product its Stripe account id in the config ("stripe": "acct_…"). The next run lights up revenue, subscriptions and MRR. A secret key is refused territory: use a restricted key, which starts with rk_.