AutoTrader DealScore Overlay Autor: Wesley M

AutoTrader DealScore Overlay

Browser extension (Chromium + Firefox) that annotates AutoTrader search result cards with a computed DealScore and optionally removes non-target UI cards/modules.

What It Does

• Adds a compact overlay badge to listing cards on AutoTrader search results pages (/cars-for-sale).
• Computes a DealScore (0-100) using:
• AutoTrader/KBB card badge signal (Great Price, Good Price, or none).
• Miles-for-year anomaly (listingMiles vs expected miles by age).
• Colors the badge by score thresholds:
• Green for good deals (>= goodDealScore)
• Red for poor deals (<= poorDealScore)
• Neutral otherwise
• Supports infinite scroll / SPA updates with MutationObserver + throttled rescans.
• Lets you toggle hiding of noisy card types/modules directly from the options page.

DealScore Model (Current)

Inputs:
- kbbValue: Great Price=1.0, Good Price=0.5, none=0.0
- normalizedKbb = (kbbValue - 0.5) * 2 -> [-1, +1]
- ageYears = max(currentYear - listingYear, 0)
- expectedMiles = max(ageYears * milesPerYear, milesPerYear)
- deltaMiles = listingMiles - expectedMiles
- normalizedMiles = clamp(-deltaMiles / milesScale, -1, +1)

Weighting:
- Raw weights from options are normalized to ratios:
- normKbbWeight = kbbWeight / (kbbWeight + milesWeight + epsilon)
- normMilesWeight = milesWeight / (kbbWeight + milesWeight + epsilon)

Final score:
- combined = normKbbWeight * normalizedKbb + normMilesWeight * normalizedMiles
- scaled = (combined + 1) / 2
- DealScore = clamp(round(scaled * 100), 0, 100)

Options

All settings are stored in the extension storage.sync area.

Scoring Parameters

• milesPerYear (default: 12000)
• milesScale (default: 20000)
• kbbWeight (default: 12)
• milesWeight (default: 10)
• goodDealScore (default: 70)
• poorDealScore (default: 40)
• debug (default: false)

Hidden Card Toggles

• hideSponsoredCards (default: true)
• hideSuggestedCards (default: true)
• hideAdModules (default: true)
• hideInlineFilterCarousel (default: true)
• hideMyWalletCard (default: true)
• hidePreorderCards (default: true)

hidePreorderCards currently targets:
- div.display-flex.fade-in
- with an immediate child matching [data-cmp="preorderCard"]

Installation (Local / Unpacked)

1. Clone this repo.
2. For Chromium/Chrome:
3. Open chrome://extensions.
4. Enable Developer mode.
5. Click Load unpacked and select src/.
6. For Firefox:
7. Open about:debugging#/runtime/this-firefox.
8. Click Load Temporary Add-on....
9. Select src/manifest.json.

Build (Local ZIPs)

Run:

npm run build


This creates:

• dist/chromium-extension-v<manifest-version>.zip
• dist/firefox-extension-v<manifest-version>.zip

To override the tag in filenames:

npm run build -- v1.3.1


Usage

1. Open AutoTrader search results (https://www.autotrader.com/cars-for-sale/...).
2. Each eligible listing card gets a badge like:
3. DealScore: 74
4. KBB: Great|Good|—
5. Miles: +/-Xk vs exp
6. Open extension popup -> Open Options to tune scoring and hide/show specific module types.

Project Structure

• src/manifest.json - MV3 manifest
• src/contentScript.js - extraction, scoring, overlays, removals, observers
• src/options.html / src/options.js - config UI + persistence
• src/popup.html / src/popup.js - quick entry to options page
• package.json - local/CI automation scripts
• scripts/build-extensions.sh - local ZIP build script
• .github/workflows/release-extension.yml - release workflow and ZIP packaging

Release Workflow

On pushes to main (or manual dispatch), GitHub Actions runs release-please and, when a release is created, packages src/ into:

• dist/chromium-extension-<tag>.zip
• dist/firefox-extension-<tag>.zip

Then uploads both ZIPs to the GitHub Release.

Firefox Store Release Workflow

The workflow .github/workflows/release-firefox.yml submits the add-on to Firefox Add-ons (AMO):

• Automatically on GitHub Release published
• Manually via Run workflow (workflow_dispatch) with optional ref and channel (listed or unlisted)

Required repository secrets:

• AMO_ADDON_ID - AMO add-on ID (slug, numeric ID, or GUID/UUID)
• AMO_JWT_ISSUER - AMO API key
• AMO_JWT_SECRET - AMO API secret

The workflow builds from src/ and submits the generated Firefox ZIP with browser-actions/release-firefox-addon@latest.

Limitations

• DOM-only approach; no network/API scraping.
• Operates on search results cards, not individual vehicle detail pages.
• Selector logic may require updates if AutoTrader changes markup.

License

See LICENSE.