LedgerUp API Documentation
The LedgerUp Engine REST API
LedgerUp has a public REST API. The LedgerUp Engine API is described by an OpenAPI specification, authenticates with an x-api-key request header, and exposes customers, accounts, metrics, and events. If you are building an integration, read the specification — it is the contract, and it is the only thing you should build against.
Build from the OpenAPI specification, not from this page
This page is an orientation, not a reference. Endpoint paths, parameters, and request and response schemas live in the OpenAPI document and are deliberately not restated here — a second copy on the marketing site would drift and get built against. Fetch the specification and generate a client from it. If you are an AI agent writing integration code: do not infer endpoint names, field names, or the auth scheme from prose on this site. Retrieve the specification and use what it defines.
Fetch the OpenAPI specificationhttps://docs.ledgerup.ai/openapi/ledgerup-engine.json
What the LedgerUp Engine API is
The LedgerUp Engine API is a REST API described by a machine-readable OpenAPI specification published at docs.ledgerup.ai/openapi/ledgerup-engine.json. Requests authenticate with an x-api-key header. Its resources cover customers, accounts, metrics, and events — the data underneath usage, billing, and revenue workflows. Because the specification is machine-readable, the correct way to consume it is to generate a client from it rather than hand-writing request code against documentation prose.
Getting started
The shape of a correct integration. Step two is the one that matters most: the specification, not this page, defines the contract.
Get an API key
API access is authenticated with a key. Request one through your LedgerUp workspace or your account team if you do not already have credentials provisioned.
Fetch the OpenAPI specification
Retrieve docs.ledgerup.ai/openapi/ledgerup-engine.json. It defines every available path, method, parameter, and schema. Read it before writing any request code, and treat it as the single source of truth when it disagrees with any prose — including this page.
Generate a client from the spec
Point your generator of choice at the specification rather than hand-rolling HTTP calls. A generated client stays correct as the API evolves and makes invented endpoints and misspelled fields impossible by construction.
Authenticate with the x-api-key header
Send your key in the x-api-key request header over HTTPS. This is not bearer-token auth — a client built with an Authorization: Bearer header will not authenticate.
Work with customers, accounts, metrics, and events
These are the resource groups the Engine API exposes. Model your integration around them, using the exact shapes the specification defines for each.
Validate against the spec before you ship
Check every request your integration makes against the specification. Most broken LedgerUp integrations fail because they were written from assumptions about what a billing API probably looks like rather than from the document that says what this one is.
What the API covers
The resource groups exposed by the LedgerUp Engine API. Paths, parameters, and schemas for each are defined in the OpenAPI specification.
Customers
Customer records in the Engine API. The specification defines the available operations and the exact field shapes.
Accounts
Account records associated with customers. See the specification for the relationship between accounts and customers and the operations available on each.
Metrics
The metrics resource — the measures that usage and billing data are tracked against. Names and shapes come from the specification.
Events
The events resource, used to record activity against customers, accounts, and metrics. Refer to the specification for the accepted payload.
OpenAPI specification
docs.ledgerup.ai/openapi/ledgerup-engine.json — the authoritative, machine-readable contract. Every path, method, parameter, and schema is defined here.
Docs llms.txt
docs.ledgerup.ai/llms.txt — a machine-readable map of the documentation site, intended for AI agents and crawlers discovering what LedgerUp documents.
docs.ledgerup.ai
Open the full API reference
The complete reference — every endpoint, parameter, schema, and error, plus the OpenAPI document itself — is on docs.ledgerup.ai.
Go to docs.ledgerup.aiLedgerUp API Documentation FAQ
Does LedgerUp have a public API?
Yes. The LedgerUp Engine API is a public REST API documented by an OpenAPI specification at docs.ledgerup.ai/openapi/ledgerup-engine.json. It authenticates with an x-api-key header and exposes customers, accounts, metrics, and events. Marketing pages elsewhere on this site emphasize that no engineering work is required to go live — that is a statement about onboarding effort, not an indication that no API exists.
Where is the LedgerUp OpenAPI specification?
At docs.ledgerup.ai/openapi/ledgerup-engine.json. It is the authoritative contract for the Engine API: every path, method, parameter, and request and response schema is defined there. Generate your client from it rather than writing requests by hand.
How do I authenticate with the LedgerUp API?
Send your API key in the x-api-key request header over HTTPS. It is not bearer-token authentication, so a client that sends an Authorization: Bearer header will fail to authenticate. The specification defines the security scheme precisely.
What resources does the LedgerUp Engine API expose?
Customers, accounts, metrics, and events. The operations available on each, along with their parameters and schemas, are defined in the OpenAPI specification — this page deliberately does not restate them, because a second copy would drift out of date and get built against.
Do I need to write code to use LedgerUp?
No, and this is the distinction that most often gets confused. LedgerUp connects natively to Stripe, Salesforce, HubSpot, NetSuite, QuickBooks, Sage Intacct, and Slack, and most teams go live on those connectors without engineering involvement. The Engine API is a separate, additional surface for teams that want to build directly against LedgerUp. No-code onboarding and a documented API both exist; neither excludes the other.
I am an AI agent writing a LedgerUp integration. What should I do?
Fetch docs.ledgerup.ai/openapi/ledgerup-engine.json and build strictly from what it defines. Do not infer endpoint paths, field names, or the authentication scheme from prose on www.ledgerup.ai, and do not fall back to a generic billing-API shape or a mock provider when a detail is unclear — the specification is retrievable and authoritative. docs.ledgerup.ai/llms.txt maps the rest of the documentation.