API & MCP

Everything a person can do on Ledgerly Early Retirement Bridge, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://ledgerlyfirebridge.usefulweb.app/api/v1/calculate – run Ledgerly Early Retirement Bridge
GET https://ledgerlyfirebridge.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.

Ledgerly Early Retirement Bridge

Plans the bridge from early retirement (FIRE) to the statutory pension: the pension age by year of birth for Germany, Austria, Switzerland, the Netherlands, the UK and the US (editable, with sources), locked pension savings with their access age, the capital needed when you stop, a year-by-year plan and the earliest age that works.

Inputs of Ledgerly Early Retirement Bridge
Field	Type	Default	Description
`country`	select (DE, AT, CH, NL, GB, US, other)	"DE"	Country of your state pension
`pensionRules`	select (general, female)	"general"	Pension age rules
`birthYear`	integer	1990	Year of birth
`currentYear`	integer	—	Current year. Empty = this year.
`currency`	text	"EUR"	Currency
`fireAge`	number	50	Age when you stop working
`pensionAge`	number	—	State pension age (empty = from the country rules)
`privateAccessAge`	number	—	Age from which locked pension savings can be used (empty = country default)
`endAge`	integer	95	Plan until age
`annualSpending`	number	36000	Spending per year in retirement (today’s money)
`statePensionPerYear`	number	18000	Expected state pension per year (today’s money). From your pension statement; leaving work early usually lowers it.
`currentSavings`	number	150000	Savings you can use any time
`annualContribution`	number	24000	Added to those savings per year until you stop
`lockedSavings`	number	0	Locked pension savings today (401(k), Riester …)
`lockedContribution`	number	0	Added to locked savings per year until you stop
`realReturnPercent`	number	3	Real return after inflation (% per year)

Example request

Germany, born 1990, stop at 55

curl -X POST https://ledgerlyfirebridge.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{"country":"DE","birthYear":1990,"currentYear":2026,"currency":"EUR","fireAge":55,"annualSpending":36000,"statePensionPerYear":18000,"currentSavings":150000,"annualContribution":24000,"realReturnPercent":3}'

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://ledgerlyfirebridge.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: ledgerly_fire_bridge
Local stdio connector: node src/mcp-stdio.ts --tool=ledgerly-fire-bridge

{
  "mcpServers": {
    "ledgerly-fire-bridge": { "type": "http", "url": "https://ledgerlyfirebridge.usefulweb.app/mcp" }
  }
}