Invoice Ninja

Invoice Ninja is an open-source invoicing, billing, payments, and expense tracking platform for freelancers and small businesses, available both as a self-hosted application and a managed SaaS at invoicing.co. The Invoice Ninja v5 REST API exposes full CRUD access to clients, invoices, quotes, payments, products, recurring invoices, expenses, projects, and tasks, authenticated with an API token (plus an optional secret) passed via HTTP headers.

Invoice Ninja publishes 10 APIs on the APIs.io network, including Activities API, Authentication API, Bank Integrations API, and 7 more. Tagged areas include Invoicing, Billing, Payments, Accounting, and Open-Source.

Invoice Ninja’s developer surface includes authentication, engineering blog, documentation, pricing, signup flow, and 6 more developer resources.

🌐 Visit website 📡 Source on GitHub

28.8/100 thin ▬ flat Agent 17/100 agent aware saas Full breakdown ↓
scored 2026-09-14 · rubric v0.22.0

1 APIs

Invoicing Billing Payments Accounting Open-Source Freelancers SMB

Kin Score

Kin Score How this is scored →
scored 2026-09-14 · rubric v0.22.0

Composite quality — 28.8/100 · thin

Contract Quality 10.1 / 19

Developer Ergonomics 4.7 / 15

Access Clarity 3.6 / 15

Operational Transparency 0.3 / 10

Contract Governance 0.0 / 9

Discoverability 5.1 / 8

Regulatory Posture 2.8 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 17/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Payments regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/invoice-ninja: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 10

Individual APIs this provider publishes, each with its own machine-readable definition.

Invoice Ninja Activities API

The Activities API from Invoice Ninja — 3 operation(s) for activities.

Invoice Ninja Authentication API

The Authentication API from Invoice Ninja — 2 operation(s) for authentication.

Invoice Ninja Bank Integrations API

The Bank Integrations API from Invoice Ninja — 3 operation(s) for bank integrations.

Invoice Ninja Bank Transaction Rules API

The Bank Transaction Rules API from Invoice Ninja — 2 operation(s) for bank transaction rules.

Invoice Ninja Bank Transactions API

The Bank Transactions API from Invoice Ninja — 3 operation(s) for bank transactions.

Invoice Ninja Charts API

The Charts API from Invoice Ninja — 4 operation(s) for charts.

Invoice Ninja Client Gateway Tokens API

The Client Gateway Tokens API from Invoice Ninja — 2 operation(s) for client gateway tokens.

Invoice Ninja Companies API

The Companies API from Invoice Ninja — 4 operation(s) for companies.

Invoice Ninja Company Gateways API

The Company Gateways API from Invoice Ninja — 2 operation(s) for company gateways.

Invoice Ninja Settings API

The Settings API from Invoice Ninja — 1 operation(s) for settings.

Scroll for all 10

Open Collections 12

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

Invoice Ninja v5 Activities API

OPEN COLLECTION

Invoice Ninja v5 Activities Authentication API

OPEN COLLECTION

Invoice Ninja v5 Activities Bank Integrations API

OPEN COLLECTION

Invoice Ninja v5 Activities Bank Transaction Rules API

OPEN COLLECTION

Invoice Ninja v5 Activities Bank Transactions API

OPEN COLLECTION

Invoice Ninja v5 Activities Charts API

OPEN COLLECTION

Invoice Ninja v5 Activities Client Gateway Tokens API

OPEN COLLECTION

Invoice Ninja v5 Activities Companies API

OPEN COLLECTION

Invoice Ninja v5 Activities Company Gateways API

OPEN COLLECTION

Invoice Ninja v5 Activities Settings API

OPEN COLLECTION

Invoice Ninja v5 API

OPEN COLLECTION

Scroll for all 12

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Invoice Ninja Authentication

apiKey · 1 scheme

SECURITY

Invoice Ninja Domain Security

TLSv1.3 · DMARC

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Invoice Ninja Agentic Access

44 operations · 29 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

Signup

Signup

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 2

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Source Code

Source Code

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Commercial 1

Pricing, plans, and the legal terms of use

Pricing

Pricing

Company 3

The organization behind the API

Blog

Blog

LinkedIn

Website

Website

Source (apis.yml)

aid: invoice-ninja
name: Invoice Ninja
description: Invoice Ninja is an open-source invoicing, billing, payments, and expense tracking platform for freelancers and
  small businesses, available both as a self-hosted application and a managed SaaS at invoicing.co. The Invoice Ninja v5 REST
  API exposes full CRUD access to clients, invoices, quotes, payments, products, recurring invoices, expenses, projects, and
  tasks, authenticated with an API token (plus an optional secret) passed via HTTP headers.
type: Index
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/invoice-ninja.png
tags:
- Invoicing
- Billing
- Payments
- Accounting
- Open-Source
- Freelancers
- SMB
tags_raw:
- Invoicing
- Billing
- Payments
- Accounting
- Open Source
- Freelancers
- SMB
url: https://raw.githubusercontent.com/api-evangelist/invoice-ninja/refs/heads/main/apis.yml
created: '2026-05-11'
modified: '2026-05-11'
specificationVersion: '0.23'
apis:
- aid: invoice-ninja:invoice-ninja-activities-api
  name: Invoice Ninja Activities API
  description: The Activities API from Invoice Ninja — 3 operation(s) for activities.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Activities
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-activities-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-authentication-api
  name: Invoice Ninja Authentication API
  description: The Authentication API from Invoice Ninja — 2 operation(s) for authentication.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Authentication
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-authentication-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-bank-integrations-api
  name: Invoice Ninja Bank Integrations API
  description: The Bank Integrations API from Invoice Ninja — 3 operation(s) for bank integrations.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Bank Integrations
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-bank-integrations-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-bank-transaction-rules-api
  name: Invoice Ninja Bank Transaction Rules API
  description: The Bank Transaction Rules API from Invoice Ninja — 2 operation(s) for bank transaction rules.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Bank Transaction Rules
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-bank-transaction-rules-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-bank-transactions-api
  name: Invoice Ninja Bank Transactions API
  description: The Bank Transactions API from Invoice Ninja — 3 operation(s) for bank transactions.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Bank Transactions
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-bank-transactions-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-charts-api
  name: Invoice Ninja Charts API
  description: The Charts API from Invoice Ninja — 4 operation(s) for charts.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Charts
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-charts-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-client-gateway-tokens-api
  name: Invoice Ninja Client Gateway Tokens API
  description: The Client Gateway Tokens API from Invoice Ninja — 2 operation(s) for client gateway tokens.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Client Gateway Tokens
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-client-gateway-tokens-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-companies-api
  name: Invoice Ninja Companies API
  description: The Companies API from Invoice Ninja — 4 operation(s) for companies.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Companies
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-companies-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-company-gateways-api
  name: Invoice Ninja Company Gateways API
  description: The Company Gateways API from Invoice Ninja — 2 operation(s) for company gateways.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Company Gateways
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-company-gateways-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
- aid: invoice-ninja:invoice-ninja-settings-api
  name: Invoice Ninja Settings API
  description: The Settings API from Invoice Ninja — 1 operation(s) for settings.
  humanURL: https://api-docs.invoicing.co
  baseURL: https://invoicing.co
  tags:
  - Settings
  properties:
  - type: OpenAPI
    url: openapi/invoice-ninja-settings-api-openapi.yml
  - type: Documentation
    url: https://api-docs.invoicing.co
  - type: Developer Guide
    url: https://invoiceninja.github.io/en/developer-guide/
  - type: APIReference
    url: https://invoiceninja.github.io/docs/api-reference/invoice-ninja-api-reference
common:
- type: AgenticAccess
  url: agentic-access/invoice-ninja-agentic-access.yml
- type: DomainSecurity
  url: security/invoice-ninja-domain-security.yml
- type: Authentication
  url: authentication/invoice-ninja-authentication.yml
- url: https://www.invoiceninja.com/blog/feed/
  type: Blog
- type: LinkedIn
  url: https://www.linkedin.com/company/invoice-ninja
- type: Website
  url: https://www.invoiceninja.com
- type: Documentation
  url: https://api-docs.invoicing.co
- type: Pricing
  url: https://www.invoiceninja.com/pricing/
- type: Signup
  url: https://app.invoicing.co/signup
- type: GitHubOrganization
  url: https://github.com/invoiceninja
- type: Source Code
  url: https://github.com/invoiceninja/invoiceninja
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

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