{ "openapi": "3.1.1", "info": { "title": "Inflation Time Machine API", "version": "1.0.0", "summary": "What was money from one year worth in another? CPI-based, 20 countries, World Bank data.", "description": "Every endpoint performs the same calculation as the human page and returns inputs, result, units, assumptions, sources, warnings and computedAt. MCP endpoint: /mcp." }, "servers": [ { "url": "https://inflationtimemachine.usefulweb.site" } ], "paths": { "/api/v1/calculate": { "post": { "operationId": "calculate", "summary": "What was money from one year worth in another? CPI-based, 20 countries, World Bank data.", "description": "Convert an amount between years with the consumer price index (2010 = 100) published by the World Bank. Shows the equivalent value, cumulative inflation, average annual inflation and lost purchasing power, with a year-by-year table.\n\nMethodology:\n- Data: World Bank WDI indicator FP.CPI.TOTL, consumer price index (2010 = 100), annual averages, snapshot stored with retrieval date.\n- Equivalent value = amount × CPI(to year) ÷ CPI(from year).\n- Cumulative inflation = (CPI(later) ÷ CPI(earlier) − 1) × 100.\n- Average annual inflation (CAGR) = ((CPI(later) ÷ CPI(earlier))^(1 ÷ years) − 1) × 100.\n- Purchasing power loss = (1 − CPI(earlier) ÷ CPI(later)) × 100: how much less the same nominal amount buys in the later year.\n- Because CPI values are annual averages, results compare average price levels of whole years, not specific dates.", "tags": [ "money" ], "x-mcp-tool": "inflation_time_machine", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/InflationTimeMachineInput" }, "examples": { "example1": { "summary": "100 EUR in Germany, 2000 → 2024", "value": { "amount": 100, "currency": "EUR", "fromYear": 2000, "toYear": 2024, "country": "DE" } }, "example2": { "summary": "1,000 USD in the US, 1980 → 2024", "value": { "amount": 1000, "currency": "USD", "fromYear": 1980, "toYear": 2024, "country": "US" } } } } } }, "responses": { "200": { "description": "Calculation result envelope.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/InflationTimeMachineResult" } } } }, "400": { "description": "Malformed JSON body.", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "422": { "description": "Invalid input (see errors[]).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "429": { "description": "Rate limit exceeded (see Retry-After).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } } } } }, "/api/v1/tool": { "get": { "operationId": "getToolDefinition", "summary": "Inputs, output schema and examples for this tool", "responses": { "200": { "description": "Tool definition.", "content": { "application/json": { "schema": { "type": "object" } } } } } } } }, "components": { "schemas": { "Problem": { "type": "object", "description": "RFC 9457 problem details. 422 responses include per-field `errors`.", "required": [ "type", "title", "status", "detail" ], "properties": { "type": { "type": "string" }, "title": { "type": "string" }, "status": { "type": "integer" }, "detail": { "type": "string" }, "code": { "type": "string" }, "errors": { "type": "array", "items": { "type": "object", "required": [ "field", "message" ], "properties": { "field": { "type": "string" }, "message": { "type": "string" } } } } } }, "InflationTimeMachineInput": { "type": "object", "additionalProperties": false, "properties": { "amount": { "title": "Amount", "type": "number", "minimum": 0, "default": 100 }, "currency": { "title": "Currency label", "description": "Label only. Use the currency of the chosen country; no conversion is done.", "type": "string", "maxLength": 8, "default": "EUR" }, "fromYear": { "title": "From year", "type": "integer", "minimum": 1960, "maximum": 2100, "default": 2000 }, "toYear": { "title": "To year", "type": "integer", "minimum": 1960, "maximum": 2100, "default": 2024 }, "country": { "title": "Country", "type": "string", "enum": [ "US", "GB", "DE", "FR", "IT", "ES", "NL", "AT", "CH", "SE", "PL", "CA", "AU", "JP", "IN", "BR", "MX", "ZA", "TR", "CN" ], "default": "DE" } }, "required": [ "amount", "fromYear", "toYear" ] }, "InflationTimeMachineResult": { "type": "object", "additionalProperties": false, "required": [ "schemaVersion", "tool", "computedAt", "inputs", "summary", "result", "units", "assumptions", "sources", "warnings", "presentation", "links" ], "properties": { "schemaVersion": { "type": "string", "const": "1.0" }, "tool": { "type": "object", "additionalProperties": false, "required": [ "id", "name", "version" ], "properties": { "id": { "type": "string" }, "name": { "type": "string" }, "version": { "type": "string" } } }, "computedAt": { "type": "string", "format": "date-time" }, "inputs": { "type": "object", "description": "Normalised inputs actually used, including applied defaults." }, "summary": { "type": "string" }, "result": { "type": "object", "additionalProperties": false, "required": [ "country", "countryName", "amount", "fromYear", "toYear", "cpiFrom", "cpiTo", "equivalentValue", "cumulativeInflationPercent", "averageAnnualInflationPercent", "purchasingPowerLossPercent", "years", "dataLastUpdated" ], "properties": { "country": { "type": "string" }, "countryName": { "type": "string" }, "amount": { "type": "number" }, "fromYear": { "type": "integer" }, "toYear": { "type": "integer" }, "cpiFrom": { "type": "number", "description": "CPI (2010 = 100) in the from-year." }, "cpiTo": { "type": "number", "description": "CPI (2010 = 100) in the to-year." }, "equivalentValue": { "type": "number", "description": "amount × CPI(to) ÷ CPI(from)." }, "cumulativeInflationPercent": { "type": "number", "description": "(CPI(to) ÷ CPI(from) − 1) × 100." }, "averageAnnualInflationPercent": { "type": "number", "description": "Compound annual rate between the earlier and later year." }, "purchasingPowerLossPercent": { "type": "number", "description": "Share of purchasing power lost from the earlier to the later year (negative = gain)." }, "dataLastUpdated": { "type": [ "string", "null" ] }, "years": { "type": "array", "items": { "type": "object", "additionalProperties": false, "required": [ "year", "cpi", "value", "inflationPercent" ], "properties": { "year": { "type": "integer" }, "cpi": { "type": "number" }, "value": { "type": "number", "description": "Amount expressed in this year's prices." }, "inflationPercent": { "type": [ "number", "null" ], "description": "Change of CPI vs. the previous listed year." } } } } } }, "units": { "type": "object", "additionalProperties": { "type": "string" } }, "assumptions": { "type": "array", "items": { "type": "string" } }, "sources": { "type": "array", "items": { "type": "object", "additionalProperties": false, "required": [ "title" ], "properties": { "title": { "type": "string" }, "url": { "type": "string" }, "publisher": { "type": "string" }, "retrievedAt": { "type": "string" }, "note": { "type": "string" } } } }, "warnings": { "type": "array", "items": { "type": "string" } }, "presentation": { "type": "array", "items": { "type": "object" }, "description": "Display blocks used by the human page (same data)." }, "links": { "type": "object", "additionalProperties": false, "required": [ "human", "api", "openapi", "methodology" ], "properties": { "human": { "type": "string", "format": "uri" }, "api": { "type": "string", "format": "uri" }, "openapi": { "type": "string", "format": "uri" }, "methodology": { "type": "string", "format": "uri" } } } } } } } }