Guides · Payment details

How do I build a payment-details validation pipeline with an AI agent?

Register iban-validate, swift-validate and vat-validate as tools on a Pydantic AI agent and give it the payment details. The agent decides which checks to run. IBAN validation is free; the SWIFT and VAT checks cost €0.03 and €0.02 a call.

Pydantic AI
Python

Steps

Install straleio and pydantic-ai.
Create the Strale client with your API key.
Define one tool function each for IBAN, SWIFT and VAT.
Run the agent with all the payment details.

The solution

Python

# pip install straleio pydantic-ai
from straleio import Strale, DoRequest
from pydantic_ai import Agent

strale = Strale(api_key="sk_live_YOUR_KEY")

agent = Agent("openai:gpt-4o")


@agent.tool_plain
def validate_iban(iban: str) -> dict:
    """Validate an IBAN and return the parsed bank code and country."""
    return strale.do(DoRequest(
        capability_slug="iban-validate",
        inputs={"iban": iban},
        max_price_cents=5,
    )).output


@agent.tool_plain
def validate_swift(swift: str) -> dict:
    """Validate a SWIFT/BIC code."""
    return strale.do(DoRequest(
        capability_slug="swift-validate",
        inputs={"swift": swift},
        max_price_cents=10,
    )).output


@agent.tool_plain
def validate_vat(vat_number: str) -> dict:
    """Check an EU VAT number against the VIES register."""
    return strale.do(DoRequest(
        capability_slug="vat-validate",
        inputs={"vat_number": vat_number},
        max_price_cents=20,
    )).output


result = agent.run_sync(
    "Validate this payment data: IBAN DE89370400440532013000, "
    "SWIFT ESSESESS, VAT SE556703748501"
)
print(result.output)

How it works

Payment details usually carry several identifiers: the recipient's IBAN, their bank's SWIFT code and the company's VAT number. Each is a separate tool, and the agent runs the checks that match what it was given. Given only an IBAN, it makes one call.

The agent can compare results across tools, for example the bank code parsed from the IBAN against the one parsed from the SWIFT code.

Use vat-validate when you need the live VIES answer and the company name. vat-format-validate only checks the format.

Each call carries its own max_price_cents ceiling, so a change in price can never spend more than you allowed.

Tools in this guide

Tool	Price per call
IBAN Validation	Free
SWIFT/BIC Validation	€0.03
EU VAT Validation	€0.02
SEPA XML Validation	€0.02

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