FRTracker — Federal Regulatory Research

Look up a CFR provision by citation (e.g. "21 CFR 1304.04") or by an exact quotation, optionally as of a past date. Returns the provision text with a ProvisionEvidence object (source, snapshot date, hashes). Explicitly reports ambiguity or no-match instead of guessing. Requires a free API key.

{
  "type": "object",
  "properties": {
    "q": {
      "type": "string",
      "description": "Citation (\"21 CFR 1304.04\") or an exact quote from regulatory text"
    },
    "as_of": {
      "type": "string",
      "description": "Optional YYYY-MM-DD snapshot upper bound (not in the future)"
    }
  },
  "required": [
    "q"
  ]
}

Documented change history for a CFR provision by canonical id (e.g. "21-cfr-1304.04(a)"): before/after text, computed redline, observed dates, and candidate final rules. 404 when the provision is not in the documented-change set — absence of a documented change is not a claim that nothing changed. No API key required.

{
  "type": "object",
  "properties": {
    "canonical_id": {
      "type": "string",
      "description": "Canonical provision id, e.g. \"21-cfr-1304.04(a)\""
    }
  },
  "required": [
    "canonical_id"
  ]
}

Which final rules amend a CFR part or section, read from each rule's own amendatory instructions ("Amend § 52.2120 by..."). Returns the rules, the sections each addresses, and dates. This reports what a rule SAYS it amends — it is not an attribution of any observed text change to that rule. Covers 2020-present; absence means not indexed, not that no rule amended it. No API key required.

{
  "type": "object",
  "properties": {
    "title": {
      "type": "string",
      "description": "CFR title number, e.g. \"40\""
    },
    "part": {
      "type": "string",
      "description": "CFR part, e.g. \"52\""
    },
    "section": {
      "type": "string",
      "description": "Optional section id, e.g. \"52.2120\". Omit for all rules touching the part."
    },
    "limit": {
      "type": "integer",
      "description": "Max rules (default 50, max 200)"
    }
  },
  "required": [
    "title",
    "part"
  ]
}

Most recent detected changes to CFR text (title, part, name, dates), newest first. No API key required.

{
  "type": "object",
  "properties": {
    "limit": {
      "type": "integer",
      "description": "Max rows (default 50, max 200)"
    }
  }
}

Aggregate corpus statistics: documents, obligations, pairs, agencies, coverage dates. No API key required.

{
  "type": "object",
  "properties": {}
}

Full-text search over Federal Register documents and extracted obligations (FTS5/BM25). Totals are approximate (total_exact: false). Requires an API key.

{
  "type": "object",
  "properties": {
    "q": {
      "type": "string",
      "description": "Search query (min 3 chars)"
    },
    "tab": {
      "type": "string",
      "enum": [
        "all",
        "fr",
        "obligations"
      ],
      "description": "Result type (default all)"
    },
    "limit": {
      "type": "integer",
      "description": "Max results (default 25, max 50)"
    },
    "page": {
      "type": "integer",
      "description": "Page number (default 1)"
    }
  },
  "required": [
    "q"
  ]
}

List Federal Register documents with filters: agency slug, document type, rulemaking pathway (interim_final/temporary/direct_final = notice-and-comment bypass classes), or docket id. Requires an API key.

{
  "type": "object",
  "properties": {
    "agency": {
      "type": "string",
      "description": "Agency slug, e.g. \"environmental-protection-agency\""
    },
    "type": {
      "type": "string",
      "enum": [
        "final_rule",
        "proposed_rule",
        "notice",
        "correction"
      ],
      "description": "Document type"
    },
    "pathway": {
      "type": "string",
      "enum": [
        "interim_final",
        "temporary",
        "direct_final",
        "final",
        "other"
      ],
      "description": "Rulemaking pathway"
    },
    "docket": {
      "type": "string",
      "description": "Docket id"
    },
    "limit": {
      "type": "integer",
      "description": "Max rows (default 25, max 100)"
    },
    "page": {
      "type": "integer",
      "description": "Page number (default 1)"
    }
  }
}

List extracted regulatory obligations ("who must do what") with filters: agency, deontic class, free text. Obligations are machine-extracted with quality tiers; they are not legal advice. Requires an API key.

{
  "type": "object",
  "properties": {
    "agency": {
      "type": "string",
      "description": "Agency slug"
    },
    "deontic": {
      "type": "string",
      "enum": [
        "MUST",
        "MUST_NOT",
        "SHOULD",
        "MAY",
        "EXEMPT"
      ],
      "description": "Deontic class"
    },
    "q": {
      "type": "string",
      "description": "Full-text filter within obligations"
    },
    "limit": {
      "type": "integer",
      "description": "Max rows (default 25, max 100)"
    },
    "page": {
      "type": "integer",
      "description": "Page number (default 1)"
    }
  }
}

Detail for one extracted obligation by id, including its source rule and citation URL. Requires an API key.

{
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "description": "Requirement id"
    }
  },
  "required": [
    "id"
  ]
}

Public comments for a Federal Register document (organization, title, date, body where available). Coverage is partial and stated in the response. Requires an API key.

{
  "type": "object",
  "properties": {
    "doc": {
      "type": "string",
      "description": "Federal Register document number, e.g. \"2024-12345\""
    },
    "offset": {
      "type": "integer",
      "description": "Row offset for pagination"
    }
  },
  "required": [
    "doc"
  ]
}