canonical: https://jentic.com/apis/partial.ly/partially

# Partial.ly Payment Plans API

Jentic publishes the only available OpenAPI specification for Partial.ly API, keeping it validated and agent-ready. Partial.ly is a payment plan solution that allows businesses to offer installment payment options to customers. The API provides programmatic access to payment plan offers, installment schedules, customer subscriptions, payment processing, and plan management, enabling automated buy-now-pay-later workflows integrated into e-commerce and billing systems.

## For AI agents

Create payment plan offers, process installment payments, manage customer subscriptions, and track payment schedules across 11 endpoints.

## Scope

Covers payment plan offer creation, installment processing, subscription management, and payment tracking. Does not handle credit underwriting, fraud detection, or direct payment gateway integration - use for installment payment plan workflows only.

## Capabilities

- Create flexible payment plan offers with custom installment schedules
- Process installment payments and track payment status
- List and manage customer payment subscriptions
- Retrieve payment plan details including schedules and balances
- Update payment plan terms and installment dates
- Query payments by status or date range
- Send payment reminders and notifications to customers
- Cancel or pause payment plans
- Refund installment payments
- Generate checkout links for payment plan acceptance

## Use cases

### E-Commerce Installment Payments

Offer buy-now-pay-later options at checkout by creating payment plan offers via POST /offer. Configure installment count, frequency, and down payment amounts, then redirect customers to the generated checkout URL. Track payment completion via GET `/offer/{id}` and process installments automatically or manually as they come due.

Example prompt: POST /offer with amount, installment count, and customer details, then redirect to checkout URL

### Subscription-Based Payment Plans

Manage recurring installment subscriptions for ongoing services or memberships. GET /plan lists all active payment plans with filtering by customer or status. Update plan terms via PATCH `/plan/{id}` to adjust installment amounts or schedules. Cancel plans with DELETE `/plan/{id}` when customers end subscriptions.

Example prompt: GET /plan?status=active to list subscriptions, then PATCH `/plan/{id}` to update terms or DELETE to cancel

### Automated Payment Collection

Process scheduled installment payments automatically by integrating with Partial.ly's payment processing. POST `/payment/{plan_id}/charge` triggers payment collection for the next installment due. Configure webhooks to receive notifications when payments succeed or fail, enabling automated retry logic and customer follow-up.

Example prompt: POST `/payment/{plan_id}/charge` to process due installment, handle webhook for success/failure, trigger retries

### AI-Driven Payment Plans via Jentic

An AI agent managing e-commerce or billing workflows can create payment plans, process installments, send reminders, and track payment status through Jentic without holding Partial.ly API keys in context. Jentic resolves intents like 'offer a 12-month payment plan' to POST /offer with the appropriate schema.

Example prompt: Search Jentic for 'create a payment plan', load POST /offer schema, and execute with customer and installment details

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| POST | `/offer` | Create a new payment plan offer |
| GET | `/offer` | List all payment plan offers with filtering |
| GET | `/offer/{id}` | Retrieve details of a specific payment plan offer |
| GET | `/plan` | List all active payment plans |
| GET | `/plan/{id}` | Retrieve a specific payment plan with schedule and status |
| PATCH | `/plan/{id}` | Update payment plan terms |
| DELETE | `/plan/{id}` | Cancel a payment plan |
| POST | `/payment/{plan_id}/charge` | Process the next installment payment |

## Key resources

- **Offers** — Payment plan offers with installment schedules, amounts, and checkout links
- **Plans** — Active payment subscriptions with customer details and payment status
- **Payments** — Individual installment payments with transaction history
- **Customers** — Customer records with payment plan associations and contact details
- **Installments** — Scheduled payment installments with due dates and amounts

## Why Jentic

- **Setup:** Wiring the Partial.ly Payment Plans API by hand means learning its bearer token auth, setting the partial.ly/api host, and building charge and error-handling logic yourself. Through Jentic you install once, import Partial.ly from the API Directory, store the token once, and your agent calls it.
- **Permission scoping:** Partial.ly puts the plan id in the URL path (`/plan/{id}`), so a rule can pin your agent to one payment plan for reads and updates. You choose the operations it may call, so destructive ones like deleting a plan or charging a plan are not included unless you add them.
- **Credential handling:** Your Partial.ly API key is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
- **Discovery method:** Agents search Jentic by intent such as 'create a payment plan offer' or 'charge an installment on a plan', and Jentic returns the matching Partial.ly operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

## Related APIs

- **Stripe API** — Full-featured payment processing with subscriptions, invoicing, and checkout
- **Affirm API** — Point-of-sale financing and installment loans for e-commerce

## FAQ

### Why is there no official OpenAPI spec for Partial.ly API?

Partial.ly publishes API documentation at https://developer.partial.ly but not a structured OpenAPI specification. Jentic generates and maintains this spec based on Partial.ly's documentation so that AI agents and developers can call Partial.ly API via structured tooling. It is validated against the live API and kept up to date. Get started with Jentic One, the self-hosted execution layer.

### What authentication does the Partial.ly API use?

The Partial.ly API uses API key authentication passed in the Authorization header. Retrieve your API key from your Partial.ly merchant account settings. Through Jentic, the key lives in the encrypted vault and is injected at execution time so it never enters agent context.

### Can I customize the installment schedule?

Yes. When creating an offer via POST /offer, you can specify installment count, frequency (weekly, bi-weekly, monthly), down payment amount, and installment amounts. The API supports flexible payment schedules tailored to your business needs.

### How do I process an installment payment?

Use POST `/payment/{plan_id}/charge` to trigger payment processing for the next scheduled installment. Partial.ly will charge the customer's saved payment method and return the transaction status. Configure webhooks to receive real-time payment success or failure notifications.

### Can customers manage their own payment plans?

Partial.ly provides customer-facing interfaces where customers can view their payment schedules, make early payments, and update payment methods. The API focuses on merchant-side plan management and payment processing. Use the customer portal URL from the plan object for customer self-service.

### What are the rate limits for the Partial.ly API?

Partial.ly does not publish specific rate limits in their public documentation. Use reasonable request patterns and implement retry logic for rate limit responses. Contact Partial.ly support for merchant-specific rate limit information and enterprise volume handling.

### Can I limit what my agent is allowed to do with the Partial.ly Payment Plans API?

Yes. Jentic One runs self-hosted on your own infrastructure, so your rules decide which Partial.ly operations and credentials the agent may use. Because Partial.ly puts the plan id in the URL path, such as GET `/plan/{id}` and PATCH `/plan/{id}`, you can pin the agent to a single payment plan for reads and updates. You also choose the exact operations it can call, so destructive ones like DELETE `/plan/{id}` or POST `/payment/{plan_id}/charge` stay off the list unless you add them.