canonical: https://jentic.com/apis/payment.uat.unifiedpost.com/unifiedpost

# Payment Uat Unifiedpost OPG Transaction Initiation

Jentic publishes the only available OpenAPI specification for OPG Transaction Initiation, keeping it validated and agent-ready. The OPG (Online Payment Gateway) Transaction Initiation API from Unifiedpost enables merchants to create payment initiation URLs for single and batch transactions. It supports generating secure payment links that redirect consumers to complete payments, covering both individual item payments and multi-item batch processing through two dedicated endpoints.

## For AI agents

Generate payment initiation URLs for single and batch transactions through Unifiedpost's Online Payment Gateway, enabling merchants to collect payments via secure redirect links.

## Scope

Does not handle payment confirmation, refunds, reconciliation, or subscription management - use for payment URL generation and transaction initiation only.

## Capabilities

- Generate secure payment initiation URLs for individual transactions
- Create batch payment initiation requests for multiple items in a single call
- Support merchant-specific payment flows via configurable merchant IDs
- Enable consumer-facing payment pages through redirect-based checkout

## Use cases

### Single Payment Link Generation

Create a one-time payment URL that redirects the consumer to a secure payment page. The merchant provides the transaction amount and details, and the API returns a URL that can be sent via email, SMS, or embedded in an invoice. The consumer completes payment on the hosted page without the merchant handling card data directly.

Example prompt: Create a single payment initiation URL for merchant {merchant_id} with amount 50.00 EUR via POST `/item/initiate/single/{merchant_id}`

### Batch Payment Initiation

Generate payment requests for multiple items or invoices in a single API call. The batch endpoint accepts an array of payment items each with their own amount and reference, returning individual payment URLs for each. This supports scenarios like monthly invoice runs where dozens of payment links need to be created simultaneously.

Example prompt: Submit a batch of 5 payment items to POST `/item/initiate/{merchant_id}` with individual amounts and references, and retrieve the generated payment URLs

### AI Agent Payment Link Creation via Jentic

AI agents use Jentic to generate payment initiation URLs without managing API authentication or constructing merchant-specific request payloads manually. Jentic provides the operation schema so agents can create payment links for invoicing workflows or e-commerce checkouts with validated inputs.

Example prompt: Search Jentic for 'create a payment link', load the OPG operation schema, and execute it to generate a payment URL for a 75.00 EUR transaction

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| POST | `/item/initiate/single/{merchant_id}` | Create a single payment initiation URL |
| POST | `/item/initiate/{merchant_id}` | Create batch payment initiation URLs |

## Key resources

- **Single Payment Initiation** — Create individual payment URLs with amount and merchant configuration
- **Batch Payment Initiation** — Generate multiple payment initiation URLs in a single request

## AI readiness

This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.

- **Score:** 56 / 100
- **Maturity:** Foundational
- **Dimensions:**
  - Foundational Compliance: 100 / 100
  - Developer Experience & Jentic Compatibility: 33 / 100
  - AI-Readiness & Agent Experience: 43 / 100
  - Agent Usability: 94 / 100
  - Security: 100 / 100
  - AI Discoverability: 50 / 100
- **View full report:** https://jentic.com/apis/payment.uat.unifiedpost.com/unifiedpost/scorecard
- **How the score is calculated:** https://docs.jentic.com/reference/api-readiness-framework/overview/
- **More about the dimensions:** https://docs.jentic.com/reference/api-readiness-framework/specification/#dimensional-model-overview

### Score it yourself

Every API in the directory is allowlisted, so you can re-score it with no key required.

- **Score your own API:** https://jentic.com/scorecard.md
- **Scoring CLI agent skill:** https://github.com/jentic/jentic-api-scorecard/blob/main/skills/jentic-api-scorecard/SKILL.md

```sh
npx @jentic/api-scorecard-cli score <openapi-url>
```

## Why Jentic

- **Setup:** Wiring the Unifiedpost OPG API by hand means handling its bearer auth against the secured payment host and building transaction initiation payloads yourself. Through Jentic you install once, import the OPG Transaction Initiation API from the API Directory, store the token once, and your agent calls it.
- **Permission scoping:** OPG puts the merchant id in the URL path (`/item/initiate/single/{merchant_id}`), so a rule can pin your agent to one merchant: it can initiate transactions for that merchant and nothing else. You choose the operations it may call, so no operation runs beyond the set you allow.
- **Credential handling:** Your Unifiedpost OPG bearer token 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 'generate a payment link for a merchant', and Jentic returns the matching OPG operation with its merchant id path parameter and payment item schema so the agent calls the right endpoint without browsing the reference docs.

## Related APIs

- **Stripe API** — Global payment platform with hosted checkout, payment links, and full lifecycle management
- **Mollie API** — European payment gateway with hosted payment pages and local payment method support
- **Adyen Checkout API** — Enterprise payment orchestration with advanced fraud detection and omnichannel support

## FAQ

### Why is there no official OpenAPI spec for OPG Transaction Initiation?

Unifiedpost does not publish an OpenAPI specification for the OPG API. Jentic generates and maintains this spec so that AI agents and developers can call OPG Transaction Initiation 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 OPG Transaction Initiation API use?

The OPG API uses Bearer token authentication. You include your merchant API token in the Authorization header. The secured base path indicates all requests require authentication. Through Jentic, the bearer token is stored in your Jentic One instance and injected into requests automatically.

### Can I create payment links for multiple invoices at once?

Yes. The POST `/item/initiate/{merchant_id}` endpoint accepts a batch of payment items in a single request. Each item includes its own amount, currency, and reference. The API returns individual payment URLs for each item, enabling bulk invoice payment link generation in one call.

### What is the difference between the single and batch endpoints?

POST `/item/initiate/single/{merchant_id}` creates one payment URL for a single transaction. POST `/item/initiate/{merchant_id}` accepts an array of items and generates multiple payment URLs in one request. Use the single endpoint for real-time checkout flows and the batch endpoint for invoice runs or scheduled billing.

### How do I generate a payment link through Jentic?

Search Jentic for 'create a payment initiation URL' to find the POST `/item/initiate/single/{merchant_id}` operation. Jentic returns the input schema showing required fields like merchant_id, amount, and currency. Execute through Jentic and receive the payment URL ready to send to your customer. Install with pip install jentic.

### Can I limit what my agent is allowed to do with the OPG Transaction Initiation API?

Yes. Because you run Jentic One yourself, your own rules decide which OPG operations and credentials your agent may use. The OPG API carries the merchant id in the URL path (POST `/item/initiate/single/{merchant_id}` and POST `/item/initiate/{merchant_id}`), so you can pin the agent to a single merchant and let it initiate payment links only for that merchant. You also choose which of the two operations it may call, so it can create single payment URLs, batch payment URLs, or neither, and nothing runs beyond the set you allow.