Developer API

Last updated July 2026

CheckBeforeYouShop tracks what dozens of shopping portals pay at each store - cashback, airline miles, and card points - with rate history and verdicts. The same data powers this public JSON API. It's free to use with attribution, read-only, and CORS-open, so browser apps and AI agents can call it directly.

Base URL

https://checkbeforeyoushop.com

Response shape

Every endpoint returns the same envelope:

{
  "data": { ... },              // the payload
  "data_as_of": "2026-07-17T…", // freshness (ISO 8601)
  "source": "CheckBeforeYouShop",
  "attribution": "Data from CheckBeforeYouShop …",
  "disclosure": "Rates are read from each portal's pages …"
}

Rates are points-native: each is returned in its own unit (pct_cash, miles_per_dollar, points_per_dollar, flat_cash, …) with a human rate_display. We never convert miles to a dollar value for you. Where a portal has a live outbound link, store responses include a go_url.

Every rate also carries a rate_kind, and the two kinds are not comparable:

earn_rate: a return on what you spend (8%, 3 mi/$). This is what a store-vs-store or portal-vs-portal comparison should rank on.
one_time_bonus: a fixed payment for a single qualifying purchase (11,200 miles, $150). It does not scale with spend, usually pays once per account, and often requires a new subscription or service. Ranking it against an earn rate by raw number is always wrong: 11,200 is not "bigger than" 3.

Endpoints

Method	Path	Returns
`GET`	`/api/v1/search.json?q=nike`	Resolve a store or portal name to its page + slug.
`GET`	`/api/v1/merchants/{slug}.json`	Every portal’s live rate for one store, the best rate per unit, and a verdict. The flagship endpoint.
`GET`	`/api/v1/portals.json`	The tracked-portal directory: currency paid, stores tracked, data freshness.
`GET`	`/api/v1/portals/{portal}.json`	One portal’s profile plus its current top rates.
`GET`	`/api/v1/highs.json`	Rates at or near the highest we have recorded right now. Earn rates are listed first; one-time bonuses follow (check rate_kind).

Example

curl https://checkbeforeyoushop.com/api/v1/merchants/nike.json

MCP server (for AI assistants)

The same data is available as a read-only Model Context Protocol server, so AI assistants (ChatGPT, Claude, Perplexity) can call it as a live tool: the cross-portal "which portal pays the most at store X" answer that a single-portal cashback app can't give. No auth, stateless streamable HTTP; add it by URL:

https://checkbeforeyoushop.com/mcp

Read-only tools, each returning the same attribution + data_as_of envelope:

compare_portal_rates: every portal's rate for a store, best-per-unit, + verdict
get_best_rate · get_rate_history · get_portal
search_stores · list_signup_bonuses · get_best_play (stacking)

History window: get_rate_history returns the last 21 days of raw changes. The derived answers aren't capped: the verdict, percentile and highest-yet fields on get_best_rate, compare_portal_rates and the REST endpoints are computed over our full archive. Need deeper raw history? Get in touch.

Fair use

Free with attribution: credit CheckBeforeYouShop and link each item's page_url.
Responses are edge-cached; please cache on your side and don't hammer the endpoints.
Rates change and can go stale: surface data_as_of and the disclosure, and send users to the portal to confirm before they shop.

Building an AI shopping agent? Point it at the MCP server above - that's the whole integration, and it covers cashback and airline miles across every portal we track.