Quickstart

One path, copy-paste, under 5 minutes.

Just want to look first? The public demo runs the same policy engine with sample data — no login.

1. Get a key

Create an account. You get a sandbox Demo workspace (no real money) and an empty Live workspace.
In Demo: Agents → Connect agent. Copy the key (starts with rg_). It is shown once and stored only as a hash.

2. Install

Python

pip install requests
# download guardrail.py from Agents → Connect agent (or /api/public/sdk/python)

Node

# download guardrail.ts from Agents → Connect agent (or /api/public/sdk/typescript)
# no dependencies — uses fetch

3. Wrap the spend

agent.py

from guardrail import Guardrail, SpendBlocked

guardrail = Guardrail(api_key="rg_...", base_url="https://railguardsecurity.com")

try:
    payment = guardrail.spend(
        amount=45.00,
        merchant="OpenAI API",
        category="AI & Compute",
        reasoning="Process 500 PDF invoices uploaded by the user.",
        rail="stripe",
    )
    print(payment["status"], payment.get("credential"))
except SpendBlocked as e:
    print("Stop or choose an alternative:", e.reason)

4. What you should see

Try three amounts against the seeded Demo policies (auto-approve under $100):

Call	SDK result	In the workspace
amount=45	status approved, sandbox card	Transactions: Approved, audit row with reasons
amount=250	waits (flagged) until a human decides	Approvals queue + in-app / Slack alert
merchant on blocklist, or over budget	raises SpendBlocked	Transactions: Blocked with the failing rule

All docs

Decision object — approved, flagged, blocked and the reasons returned
Approvals — queue, alerts and signed decision webhooks
Payment rails — Stripe Issuing, Ramp, USDC (Preview)
Audit & export — append-only log, retention, CSV/JSON
API reference — endpoints, auth, rate limits, errors
SDKs — Python and TypeScript guardrail
MCP — tools over JSON-RPC
Idempotency & retries — no second card on retry
Security — data flow, keys, subprocessors