# Numina Developers

> Numina is a Danish accounting platform built around a double-entry ledger. Its REST API and MCP server let apps and AI assistants read a company's books, post journal entries, and manage contacts, products and invoices.

Notes for agents:

- Base URL: https://api.numina.app. Authenticate with `Authorization: Bearer <token>`, where the token is an API key (`numi_...`) or an OAuth access token. Each token belongs to exactly one company.
- Amounts follow double-entry signs: positive is debit (expenses, assets), negative is credit (income, liabilities). Lines in a journal entry must sum to 0.
- Journal entries and invoices are created as drafts. A person books them in Numina, or the API does with the `journal:book` or `invoices:book` scope. Booking through the API is the caller's own approval, Numina does not review it, and a booked entry cannot be changed through the API.
- Scopes are per resource and action (`journal:read`, `invoices:write`, `journal:book`); `GET /v1/me` shows what a token can do.
- For AI assistants, prefer the MCP server at https://api.numina.app/mcp over calling REST yourself.
- The OpenAPI document at https://developers.numina.app/openapi.json is the source of truth for every field.

## Get started

- [Quickstart](https://developers.numina.app/quickstart.md): Create an API key, read a company's chart of accounts and post your first draft journal entry in about five minutes.
- [Authentication](https://developers.numina.app/authentication.md): Authenticate with an API key for your own company, or with OAuth 2.1 and PKCE for an app that other Numina companies connect to.
- [Build an integration](https://developers.numina.app/build-an-integration.md): Connect your product to your customers' books in Numina, from a first test connection to pilot customers and a reviewed partner app.
- [Numina MCP](https://developers.numina.app/mcp.md): Connect Claude, ChatGPT, Cursor or any MCP client to a company's books. The assistant reads the ledger and writes drafts that a person books.

## Concepts

- [The accounting model](https://developers.numina.app/accounting-model.md): How amounts, signs, VAT, drafts and booking work in Numina, and what that means for the data you send and read.
- [Errors](https://developers.numina.app/errors.md): Every error has the same JSON shape with a stable machine-readable code. Branch on the code, show the description, and read details for field errors.
- [Idempotency](https://developers.numina.app/idempotency.md): Send an Idempotency-Key header so a request retried after a timeout returns the first result instead of creating a second journal entry or invoice.
- [Pagination](https://developers.numina.app/pagination.md): List endpoints page with limit and offset, and tell you whether there is more with has_more and next_offset.
- [Rate limits](https://developers.numina.app/rate-limits.md): Each API key or OAuth connection can make 600 requests per minute. Limits are never per IP address, and responses carry RateLimit headers.

## API reference

- [Introduction](https://developers.numina.app/api.md): Conventions, base URL and resources
- [Company](https://developers.numina.app/api/company.md): The connected company, its accounting years, and a check of your credentials.
  - [Check credentials](https://developers.numina.app/api/company/check-credentials.md): `GET /v1/me`
  - [Get company](https://developers.numina.app/api/company/get-company.md): `GET /v1/company`
  - [List accounting years](https://developers.numina.app/api/company/list-accounting-years.md): `GET /v1/accounting-years`
- [Accounts](https://developers.numina.app/api/accounts.md): Chart of accounts and VAT codes.
  - [List accounts](https://developers.numina.app/api/accounts/list-accounts.md): `GET /v1/accounts`
  - [List VAT codes](https://developers.numina.app/api/accounts/list-vat-codes.md): `GET /v1/vat-codes`
- [Journal Entries](https://developers.numina.app/api/journal-entries.md): Create, change and book entries. Create a draft, upload its document, then book it.
  - [List journal entries](https://developers.numina.app/api/journal-entries/list-journal-entries.md): `GET /v1/journal-entries`
  - [Create journal entry](https://developers.numina.app/api/journal-entries/create-journal-entry.md): `POST /v1/journal-entries`
  - [Get journal entry](https://developers.numina.app/api/journal-entries/get-journal-entry.md): `GET /v1/journal-entries/{id}`
  - [Update draft journal entry](https://developers.numina.app/api/journal-entries/update-draft-journal-entry.md): `PUT /v1/journal-entries/{id}`
  - [Delete draft journal entry](https://developers.numina.app/api/journal-entries/delete-draft-journal-entry.md): `DELETE /v1/journal-entries/{id}`
  - [Book journal entry](https://developers.numina.app/api/journal-entries/book-journal-entry.md): `POST /v1/journal-entries/{id}/book`
- [Attachments](https://developers.numina.app/api/attachments.md): Documents (bilag). File contents cannot be downloaded through the API.
  - [Upload attachment](https://developers.numina.app/api/attachments/upload-attachment.md): `POST /v1/journal-entries/{id}/attachments`
  - [Add files to an empty attachment](https://developers.numina.app/api/attachments/add-files-to-an-empty-attachment.md): `POST /v1/attachments/{id}/files`
  - [List documents](https://developers.numina.app/api/attachments/list-documents.md): `GET /v1/attachments`
  - [Upload document to the inbox](https://developers.numina.app/api/attachments/upload-document-to-the-inbox.md): `POST /v1/attachments`
  - [Get document](https://developers.numina.app/api/attachments/get-document.md): `GET /v1/attachments/{id}`
- [Ledger entries](https://developers.numina.app/api/ledger-entries.md): Posted entries, as the reports read them.
  - [List booked ledger entries](https://developers.numina.app/api/ledger-entries/list-booked-ledger-entries.md): `GET /v1/ledger-entries`
- [Balances](https://developers.numina.app/api/balances.md): Trial balance and movement per period. Booked entries only.
  - [Get trial balance (saldobalance)](https://developers.numina.app/api/balances/get-trial-balance.md): `GET /v1/trial-balance`
  - [Get account movement per period](https://developers.numina.app/api/balances/get-account-movement-per-period.md): `GET /v1/account-balances`
- [Bank](https://developers.numina.app/api/bank.md): Bank accounts, and bank lines with their reconciliation state. Read-only.
  - [List bank accounts](https://developers.numina.app/api/bank/list-bank-accounts.md): `GET /v1/bank-accounts`
  - [List bank lines](https://developers.numina.app/api/bank/list-bank-lines.md): `GET /v1/bank-transactions`
  - [Get bank line](https://developers.numina.app/api/bank/get-bank-line.md): `GET /v1/bank-transactions/{id}`
- [Contacts](https://developers.numina.app/api/contacts.md): Customers and suppliers.
  - [List contacts](https://developers.numina.app/api/contacts/list-contacts.md): `GET /v1/contacts`
  - [Create contact](https://developers.numina.app/api/contacts/create-contact.md): `POST /v1/contacts`
  - [Get contact](https://developers.numina.app/api/contacts/get-contact.md): `GET /v1/contacts/{id}`
  - [Update contact](https://developers.numina.app/api/contacts/update-contact.md): `PUT /v1/contacts/{id}`
- [Products](https://developers.numina.app/api/products.md): The product catalogue used on invoice lines.
  - [List products](https://developers.numina.app/api/products/list-products.md): `GET /v1/products`
  - [Create product](https://developers.numina.app/api/products/create-product.md): `POST /v1/products`
  - [Get product](https://developers.numina.app/api/products/get-product.md): `GET /v1/products/{id}`
  - [Update product](https://developers.numina.app/api/products/update-product.md): `PUT /v1/products/{id}`
  - [Delete product](https://developers.numina.app/api/products/delete-product.md): `DELETE /v1/products/{id}`
- [Invoices](https://developers.numina.app/api/invoices.md): Create, book and send invoices. Credit notes and offers are created in Numina and can be read here.
  - [List invoices](https://developers.numina.app/api/invoices/list-invoices.md): `GET /v1/invoices`
  - [Create invoice](https://developers.numina.app/api/invoices/create-invoice.md): `POST /v1/invoices`
  - [Get invoice](https://developers.numina.app/api/invoices/get-invoice.md): `GET /v1/invoices/{id}`
  - [Delete draft invoice](https://developers.numina.app/api/invoices/delete-draft-invoice.md): `DELETE /v1/invoices/{id}`
  - [Download invoice PDF](https://developers.numina.app/api/invoices/download-invoice-pdf.md): `GET /v1/invoices/{id}/pdf`
  - [Book draft invoice](https://developers.numina.app/api/invoices/book-draft-invoice.md): `POST /v1/invoices/{id}/book`
  - [Credit invoice](https://developers.numina.app/api/invoices/credit-invoice.md): `POST /v1/invoices/{id}/credit-notes`
  - [Send invoice by email](https://developers.numina.app/api/invoices/send-invoice-by-email.md): `POST /v1/invoices/{id}/send`

## Specs

- [OpenAPI 3 document](https://developers.numina.app/openapi.json): Every endpoint, parameter and schema

## Optional

- [Every page in one file](https://developers.numina.app/llms-full.txt): All guides and endpoints concatenated as Markdown
- [Numina](https://numina.app/llms.txt): The product, pricing and company