Invoice Ninja

Name: Invoice Ninja API
Brand: Invoice Ninja
Availability: InStock

★ Only Publicly Available OpenAPI DocumentFinanceAccountingnone331 EndpointsREST

For Agents

Issue invoices, record payments, track expenses, and manage clients in Invoice Ninja so an agent can run an end-to-end billing workflow.

Install Jentic One Beta

Connect the Invoice Ninja to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Invoice Ninja, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.

Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.

Step 1: Jentic One Host machine

# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh

Step 2: Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register       # connects your agent to your Jentic One instance

Jentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.

Capabilities

What an agent can do with Invoice Ninja API.

Issue invoices and quotes to clients with line items, tax rates, and custom designs

Record client payments and apply them across one or more outstanding invoices

Manage recurring invoices and dunning schedules for subscription-style billing

GET STARTED

Start building with Invoice Ninja API

Explore with Jentic

View OpenAPI Document

Jentic publishes the only available OpenAPI specification for Invoice Ninja, keeping it validated and agent-ready. Invoice Ninja is an open-source invoicing, billing, and time-tracking platform that lets businesses issue invoices, accept online payments, manage clients, and reconcile bank transactions. The API exposes 331 endpoints covering invoices, quotes, recurring invoices, credits, payments, expenses, projects, tasks, vendors, bank integrations, and webhooks. It is built for service businesses, freelancers, and agencies that want to run their full quote-to-cash workflow programmatically.

Use Cases

Patterns agents use Invoice Ninja API for, with concrete tasks.

★ Freelance Quote-to-Cash

Freelancers and small agencies can run their full quote-to-cash workflow against Invoice Ninja: create a client, send a quote, convert it to an invoice once approved, email it from the client portal, and reconcile the payment when it arrives. The 331-endpoint API covers clients, quotes, invoices, payments, and credits, so an integration replaces the manual portal click-through.

Create a client, issue a $1,500 invoice with two line items, email it via the client portal, and confirm payment via the /api/v1/payments endpoint.

Subscription and Recurring Billing

Service businesses with monthly retainers can use the recurring_invoices endpoints to schedule billing cycles, auto-bill saved payment methods, and apply credits when clients pause. Invoice Ninja handles the dunning and the schedule; agents trigger creation, pause, or resume programmatically without touching the admin UI.

Create a recurring invoice template for $99/month with auto-billing enabled and schedule the first cycle for next Monday.

Bank Reconciliation Workflow

Operations teams can pull imported bank transactions through the bank_integrations and bank_transactions endpoints, match them against open invoices, and create expense records for outflows. The Yodlee integration handles the feed; the API exposes the matched and unmatched transactions for review.

List unmatched bank transactions, match the deposit of $1,500 to invoice INV-1042, and mark the invoice as paid.

Agent-Driven Accounts Receivable

An AI agent connected via Jentic can run weekly AR collection: pull all overdue invoices, send a polite reminder through the API, log a follow-up activity, and report which clients still need a phone call. The agent uses Jentic to discover the invoices, payments, and activities operations without browsing the 331-endpoint spec.

Find every invoice past due by more than 14 days, send a reminder email through Invoice Ninja, and log an activity for each client.

Key Endpoints

331 endpoints — jentic publishes the only available openapi specification for invoice ninja, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

GET

/api/v1/invoices

List invoices

POST

/api/v1/invoices

Create an invoice

POST

/api/v1/payments

Record a payment

POST

/api/v1/recurring_invoices

Create a recurring invoice

GET

/api/v1/clients

List clients

POST

/api/v1/quotes

Create a quote

GET

/api/v1/bank_integrations

List bank integrations

GET

/api/v1/invoices

List invoices

POST

/api/v1/invoices

Create an invoice

POST

/api/v1/payments

Record a payment

POST

/api/v1/recurring_invoices

Create a recurring invoice

GET

/api/v1/clients

List clients

POST

Why Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Invoice Ninja API tokens are stored encrypted in the Jentic vault. Agents receive a scoped reference and the X-Api-Token header is injected at execution time, so the raw token never enters the agent's context.

Intent-based discovery

Agents search Jentic by intent ('issue an invoice', 'mark invoice paid') and Jentic returns the matching Invoice Ninja operation with its input schema, so the agent calls the right endpoint without browsing 331 paths.

Time to first call

Direct Invoice Ninja integration: 1-3 days for auth, schema mapping, and webhook handling. Through Jentic: under an hour to search, load, and execute.

FAQs

Specific to using Invoice Ninja API through Jentic.

Why is there no official OpenAPI spec for Invoice Ninja?

Invoice Ninja does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Invoice Ninja via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does the Invoice Ninja API use?

Invoice Ninja uses an X-Api-Token header issued from the user account settings. The published OpenAPI document does not declare a securityScheme, so the token is sent as a custom header on every request. Through Jentic the token is stored in the encrypted vault and only a scoped reference is exposed to the agent.

Can I create a recurring invoice through the Invoice Ninja API?

Yes. POST to /api/v1/recurring_invoices to create the template, set frequency_id and next_send_date, and enable auto_bill to charge a saved payment method on each cycle. The endpoint returns the recurring invoice id which you can pause or resume later.

What are the rate limits for the Invoice Ninja API?

Self-hosted instances do not enforce a rate limit by default; the hosted ninja.invoicing.co service applies per-account throttling that is documented in the account settings rather than the OpenAPI spec. Run the spec against your own ninja.test or hosted base URL and back off on 429 responses.

How do I issue an invoice through Invoice Ninja with Jentic?

Search Jentic for 'create an invoice in Invoice Ninja', load the schema for POST /api/v1/invoices, then execute with client_id and line_items. The full flow is: pip install jentic, then await client.search, await client.load, await client.execute.

Does the Invoice Ninja API support webhooks?

Yes. The /api/v1/webhooks endpoints let you register a target URL and subscribe to events such as invoice.created, payment.created, and quote.approved so an agent can react when a client interacts with the portal.

Invoice Ninja

Connect the Invoice Ninja to your agent

Capabilities

Start building with Invoice Ninja API

Use Cases

Key Endpoints

Why Jentic?

Related APIs

FAQs