generated: '2026-08-14'
method: searched
source: https://apidocs.callrail.com/#swap-js
description: >-
  CallRail's only client-side component surface is swap.js, the Dynamic Number Insertion script.
  It is a per-company hosted script that rewrites phone numbers in the DOM to the correct tracking
  number and captures form submissions, and it exposes a small documented JavaScript API for
  advanced/SPA use. There is no element library, no embeddable dashboard, and no npm-distributed
  UI package.
families:
  - name: swap.js
    kind: hosted-script
    purpose: Dynamic Number Insertion (DNI) and form submission capture
    distribution: >-
      Company-specific script served by CallRail and installed on the customer's website; not
      published to npm or a CDN registry, so there is no package version to record.
    version: null
    version_note: >-
      Unversioned in the customer-facing distribution — the script tag is issued per company and
      floats to whatever CallRail currently serves. A consumer cannot pin or tell what they are
      getting.
    docs: https://apidocs.callrail.com/#swap-js
    html_api:
      - attribute: data-calltrk-noswap
        applies_to: any element
        description: >-
          Marks an element (and its children) as excluded from number swapping. Useful to keep the
          original number visible in one region, or to skip large regions for performance.
      - attribute: data-calltrk-nosubmit
        applies_to: form elements
        description: >-
          Documented in the Form Submission section as the markup opt-out for form capture.
        confidence: medium
        note: >-
          Named in the docs' Form Submission HTML Markup example; recorded as documented, not
          verified against a live page.
    javascript_api:
      - name: CallTrk.swap(nodeOrSelector)
        description: >-
          Re-scans the DOM and attempts to swap phone numbers again. Parameter optional — omitted,
          processing starts at document.body. A DOM node scopes to that node and its children; a
          CSS selector is resolved with document.querySelectorAll (no jQuery dependency).
        use_case: Content added to the page after initial load.
      - name: CallTrk.getSwapNumbers(numbers, callback)
        description: >-
          Returns the swap settings for the current page so the caller can perform number insertion
          manually. Accepts an array of 10-digit numbers with no separators; the callback receives
          an object keyed by swap target with the tracking number to display. Asynchronous — a
          request to CallRail servers may be required — so the callback must be used rather than
          the return value.
        use_case: Single-page applications whose templating engine would otherwise overwrite swapped numbers.
        caveats:
          - Queried numbers may have no replacement if the swap target is unknown or the keyword pool is temporarily exhausted.
          - The caller is responsible for locale-appropriate formatting of the returned number.
gaps:
  - No versioned/pinnable distribution of swap.js and no published changelog for it.
  - No npm package, no TypeScript types, no integrity hash for the script tag.
  - No embeddable reporting or dashboard component.