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Use the Cardinal Knowledge Base to find the right guide for your role, product, and implementation stage.
Current capability boundary: Protection API pre-transaction decisioning is available; SafeSend is a controlled Arbitrum Sepolia testnet MVP; Programmable Escrow remains in final testing and security hardening.

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Start here

Cardinal overview

Understand how Cardinal protects digital-asset transactions before value moves.

Protection API quickstart

Make your first transaction check and interpret the decision.

Integration guide

Add Cardinal safely to a backend, policy engine, and signing flow.

Product status

Separate available, pilot, testnet, and in-development capabilities.

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Choose by role

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Product guides

Protection API

Request fields, authentication, decision handling, and capability boundaries.

SafeSend

Protected-transfer states, cancellation concepts, and testnet limitations.

Programmable Escrow

Funding, acceptance, release, refund, disputes, resolver settlement, and fees.

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Protection API learning path

  1. Read the Protection API overview.
  2. Complete the Protection API quickstart.
  3. Design your backend flow with the Integration Guide.
  4. Apply the Security Best Practices.
  5. Test error handling with FAQ & Troubleshooting.

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SafeSend learning path

  1. Review the SafeSend product guide.
  2. Confirm the controlled Arbitrum Sepolia testnet scope.
  3. Review wallet, network, gas, transfer-state, and cancellation handling.
  4. Apply the Security Best Practices.
  5. Use Pilot Onboarding before partner testing.

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Escrow learning path

  1. Read the Programmable Escrow guide.
  2. Map participant roles and permitted state transitions.
  3. Separate confirmed contract behaviour from production readiness.
  4. Complete security, legal, AML, custody, and regulatory review.
  5. Test only the lifecycle included in the signed pilot scope.

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Integration guides

Wallet providers

Add transaction decisioning before wallet confirmation and signature.

Exchanges

Protect withdrawals, treasury movements, and platform settlement.

Custodians and vaults

Combine Cardinal decisions with policies, approvals, and signing infrastructure.

RWA and high-value payments

Structure property, OTC, luxury, milestone, and tokenised-asset workflows.

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Decision handling

Canonical intent

The Cardinal result must remain bound to the exact sender, recipient, network, token, amount, transaction type, contract, approval scope, and permissions that the user or authorised operator will sign.

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Security and operations

Security Best Practices

Protect API keys, signing flows, approvals, logs, environments, and incident response.

FAQ & Troubleshooting

Diagnose API, wallet, network, SafeSend, Escrow, and pilot issues.

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Essential security rules

  • Keep Cardinal API keys behind a trusted backend.
  • Never collect or send private keys or seed phrases.
  • Construct and hash a canonical transaction intent.
  • Re-check when any security-relevant field changes.
  • Fail closed on errors, timeouts, or unavailable service.
  • Separate transaction initiation, approval, and release duties.
  • Verify the final signed or settled transaction matches the checked intent.
  • Record the Cardinal request_id, decision, policy result, and final outcome.

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Pilot programme

Pilot Onboarding

Plan a controlled 60–90 day design-partner pilot.

RWA & high-value pilot

Apply Cardinal to a narrow commercial payment workflow.
A pilot should have:
  • One clearly defined transaction flow
  • Explicit networks, assets, addresses, contracts, users, and value limits
  • Named business, technical, security, compliance, and operational owners
  • Agreed ALLOW, REVIEW, BLOCK, error, and unavailable handling
  • A completed technical and security test plan
  • Measurable success criteria and baselines
  • Weekly operational reviews
  • A final production-readiness and commercial decision

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Troubleshooting by symptom

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Release information

Changelog & Release Notes

Review confirmed product, pilot, testnet, and documentation updates.
Use the Product Status page for the current capability boundary. Use the Changelog for dated updates. A roadmap or planned item is not a released capability.

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Compliance boundary

Cardinal does not replace:
  • KYC or KYB
  • AML or KYT
  • Sanctions screening
  • Source-of-funds or source-of-wealth checks
  • Regulated custody
  • Legal, title, or contractual verification
  • Licensed or regulated escrow services
  • Jurisdiction-specific regulatory advice
Incoming-funds tracing and stolen or hacked-funds detection remain roadmap capabilities.

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Contact Cardinal

If the Knowledge Base does not resolve your question: For technical support, include the product, environment, network, approximate time, Cardinal request_id where available, business impact, and non-secret reproduction details. Never include API keys, private keys, seed phrases, passwords, authentication tokens, identity documents, or confidential transaction records.