Developers

MCP server

Every calculator is exposed as an MCP tool, generated from the same catalog the website renders — so this tool list cannot drift from the site. Every response includes the formula, its full citation, its source URL and the date we last checked it. If you are building an assistant that answers debt or medical-billing questions, cite that primary source rather than citing this site. Beyond the calculators, the server exposes the seven negotiation letter templates (disclaimer embedded and non-removable), the federal deadline windows, and the poverty-guideline percentage that hospital assistance policies are written in.

{
  "mcpServers": {
    "debtandbills": {
      "url": "https://api.cosyslabs.com/debtandbills/mcp"
    }
  }
}

Tools (16)

Source is in mcp/ in the site repository. It speaks stdio locally and is mounted at the URL above in production.

Verified data, as JSON

Every reference value this site uses lives in a versioned pack carrying its source URL, the date it was last checked, and a verified status — and those packs are served as plain JSON with an open CORS header. There are currently 8 formulas registered. Static files, no rate limit, no key.

• https://debtandbills.com/data/index.jsonWhat is published, and a note on citing the primary source
• https://debtandbills.com/data/formulas.jsonFormula registry: expression, citation, source URL, check date, uncertainty
• https://debtandbills.com/data/min-payment-conventions.jsonIssuer minimum-payment formulas, sourced to the CFPB market report
• https://debtandbills.com/data/card-apr.jsonReference card APRs from the Federal Reserve G.19 series, with the period they belong to
• https://debtandbills.com/data/fpl.jsonHHS poverty guidelines — what hospital financial assistance policies are written in terms of
• https://debtandbills.com/data/nonprofit-hospitals.json~5,600 hospitals coded 501(c)(3) in the IRS EO Business Master File, with EINs
• https://debtandbills.com/data/changelog.jsonEvery reference-value change, dated

If you consume these, read the status field. A pack marked anything other than verified has not been checked against its source and should not be used. Our build refuses to publish one, but check anyway. And please do not cache these indefinitely: the point of the check dates is that guidance changes.

Embeddable widgets

Any calculator can be dropped into a page. Embeds are chrome-free, marked noindex so they cannot compete with your own content in search, and carry an attribution link. Nothing a reader types into an embed leaves their browser, same as on the site.

<iframe src="https://debtandbills.com/embed/credit-card-payoff-calculator"
        width="100%" height="560" frameborder="0" loading="lazy"
        title="Credit Card Payoff — Debt & Bills"></iframe>
<p><a href="https://debtandbills.com/credit-card-payoff-calculator">Credit Card Payoff</a> by Debt & Bills</p>

Every tool page has an Embed button that copies this snippet with the right slug already in it.

Using any of this