API & MCP

Everything a person can do on Blackjack Basic Strategy Calculator, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://playcardsblackjackstrategy.usefulweb.app/api/v1/calculate – run Blackjack Basic Strategy Calculator
GET https://playcardsblackjackstrategy.usefulweb.app/api/v1/tool – inputs, output schema, examples
OpenAPI 3.1: /openapi.json · /openapi.yaml
Errors: application/problem+json; 422 includes per-field errors.

Blackjack Basic Strategy Calculator

Computes the blackjack basic strategy for the rules at your table — number of decks, dealer hits or stands on soft 17, double after split, late surrender, which totals may double, 3:2 or 6:5 — from the exact dealer probabilities of the shoe, not from a copied chart. Enter a hand and the dealer’s up card to see the expected value of hit, stand, double, split and surrender. Play money and learning only: basic strategy lowers the house edge but never beats it.

Inputs of Blackjack Basic Strategy Calculator
Field	Type	Default	Description
`decks`	select (1, 2, 4, 6, 8)	"6"	Decks
`h17`	boolean	false	Dealer hits soft 17
`das`	boolean	true	Double after split allowed
`surrender`	boolean	false	Late surrender allowed
`doubleOn`	select (any, 9-11, 10-11)	"any"	Double on
`bjPays`	select (3:2, 6:5)	"3:2"	Blackjack pays
`hand`	text	—	Your two cards (optional). Ranks 2–10, J, Q, K, A separated by a comma.
`dealer`	select (, 2, 3, 4, 5, 6, 7, 8, 9, 10, A)	—	Dealer up card (optional)

Example request

6 decks, dealer stands on soft 17, double after split

curl -X POST https://playcardsblackjackstrategy.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{"decks":"6","h17":false,"das":true}'

Every result contains

inputs (normalised, defaults applied), summary, result (validated against the published schema), units, assumptions, sources, warnings, computedAt and links.

MCP (Model Context Protocol)

Streamable HTTP endpoint: https://playcardsblackjackstrategy.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: playcards_blackjack_strategy
Local stdio connector: node src/mcp-stdio.ts --tool=playcards-blackjack-strategy

{
  "mcpServers": {
    "playcards-blackjack-strategy": { "type": "http", "url": "https://playcardsblackjackstrategy.usefulweb.app/mcp" }
  }
}