---
title: "Free public market snapshot (no key or usage charge)"
method: GET
path: "/v1/index"
---

# Free public market snapshot (no key or usage charge)

`GET /v1/index`

## Request

- Base URL: `https://api.theusedcarindex.com`
- URL: `https://api.theusedcarindex.com/v1/index`
- Auth: none required

Observed dealer inventory, with prices and mileage as last recorded (price increases and mileage-only changes are not recorded), and the latest 30 days of events. Delisted never establishes a sale. Empty data returns 200. Public cache lifetime is 300 seconds; ETag supports conditional requests.

## Query parameters

- `download` '1': Download the same JSON as a dated attachment.

## Response `200`

Success

- MarketIndex
  - `schema_version` unknown, required
  - `name` 'The Used Car Index market snapshot', required
  - `status` 'ok' | 'empty', required
  - `as_of` string, nullable, required
  - `generated_from` object, required
    - `listing_events_through_id` integer, required
    - `first_event_date` string, nullable, required
    - `latest_event_date` string, nullable, required
    - `event_days` integer, required
    - `nhtsa_data_built_at` string, nullable, required
    - `sources` object[], required
      - `name` string, required
      - `detail` string, required
  - `coverage` object, required
    - `region` 'Chicago area', required
    - `dealers_registered` integer, required
    - `dealers_collecting` integer, required
    - `dealers_with_active_listings` integer, required
    - `last_collector_run_at` string, nullable, required
    - `dealers` object[], required
      - `name` string, required
      - `site_url` string, required
      - `active_listings` integer, required
    - `dealers_truncated` boolean, required
    - `basis` string, required
  - `inventory` object, required
    - `active_listings` integer, required
    - `delisted_listings` integer, required
    - `tracked_listings` integer, required
    - `priced_listings` integer, required
    - `listings_with_mileage` integer, required
    - `median_price` number, nullable, required
    - `median_mileage` number, nullable, required
    - `basis` string, required
  - `latest_day` object, required
    - `date` string, nullable, required
    - `new` integer, required
    - `price_drops` integer, required
    - `relisted` integer, required
    - `delisted` integer, required
    - `median_price_drop_amount` number, nullable, required
    - `median_price_drop_percent` number, nullable, required
    - `basis` string, required
  - `window` object, required
    - `days` unknown, required
    - `start` string, nullable, required
    - `end` string, nullable, required
    - `new` integer, required
    - `price_drops` integer, required
    - `relisted` integer, required
    - `delisted` integer, required
    - `median_price_drop_amount` number, nullable, required
    - `median_price_drop_percent` number, nullable, required
    - `basis` string, required
  - `nhtsa_exposure` object, required
    - `level` 'model_year', required
    - `matched_listings` integer, required
    - `unmatched_listings` integer, required
    - `with_recall_campaign` integer, required
    - `with_open_investigation` integer, required
    - `with_either` integer, required
    - `share_with_either` number, nullable, required
    - `basis` string, required
    - `caveat` string, required
  - `makes` object[], required
    - `make` string, required
    - `make_key` string, required
    - `active_listings` integer, required
    - `share_of_active` number, required
    - `priced_listings` integer, required
    - `median_price` number, nullable, required
    - `listings_with_mileage` integer, required
    - `median_mileage` number, nullable, required
  - `models` object[], required
    - `make` string, required
    - `make_key` string, required
    - `active_listings` integer, required
    - `share_of_active` number, required
    - `priced_listings` integer, required
    - `median_price` number, nullable, required
    - `listings_with_mileage` integer, required
    - `median_mileage` number, nullable, required
    - `model` string, required
    - `family_key` string, required
    - `matched_listings` integer, required
    - `with_either` integer, required
  - `trend` object, required
    - `window_days` unknown, required
    - `days_with_data` integer, required
    - `has_history` boolean, required
    - `days` object[], required
      - `date` string, required
      - `new` integer, required
      - `price_drops` integer, required
      - `relisted` integer, required
      - `delisted` integer, required
      - `net_change` integer, required
      - `active_end_of_day` integer, required: Current active inventory minus later net changes; derived, not a stored snapshot.
      - `median_new_price` number, nullable, required
      - `new_priced` integer, required
      - `median_price_drop_amount` number, nullable, required
    - `basis` string, required
    - `note` string, required
  - `methodology` object, required
    - `counted` string[], required
    - `delisted_means` string[], required
    - `coverage_notes` string[], required
    - `limits` string[], required

## Other responses

- `304`: Unchanged snapshot; empty body.
- `400`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `401`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `403`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `404`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `405`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `413`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `415`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `429`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `500`: RFC 9457 problem with stable code; 429 includes Retry-After.
- `503`: RFC 9457 problem with stable code; 429 includes Retry-After.

---

[API](https://skmtc.dev/theusedcarindex/apis/the-used-car-index.md) · [All operations](https://skmtc.dev/theusedcarindex/apis/the-used-car-index/llms.txt) · [OpenAPI document](https://skmtc.dev/theusedcarindex/apis/the-used-car-index/revisions/80dd1305d05c?raw)