Posten.no E-Signature Integration

[Starefossen]

Summary

Integrate with Posten Signering for legally binding digital signatures via BankID.

Reference: https://signering.posten.no/priser

Implementation

src/lib/posten-signering/client.ts

• OAuth2 enterprise authentication
• createSigningTask(pdf, signerEmail, signerName) - upload PDF, create signing task
• getTaskStatus(taskId) - poll for status
• downloadSignedDocument(taskId) - retrieve signed PDF

tRPC Endpoints

• crm.contract.sendToSigning - generate PDF, create Posten task, update status
• crm.contract.checkStatus - manual status check

Webhook Handler

• src/app/api/webhooks/posten-signering/route.ts
• Receive signing events (completed, declined, expired)
• Update signature_status and contract_status
• Store signed PDF in Sanity
• Trigger welcome email on completion

Environment Variables

• POSTEN_SIGNERING_CLIENT_ID
• POSTEN_SIGNERING_CLIENT_SECRET
• POSTEN_SIGNERING_WEBHOOK_SECRET

Acceptance Criteria

• PDF successfully uploaded to Posten.no
• Sponsor receives BankID signing request
• Webhook updates CRM status on signature
• Signed PDF stored in Sanity

Dependencies

• Schema Extensions for Contract Signing #300 (Schema Extensions)
• Contract Template System #301 (Contract Template System / PDF generation)

Part of

Epic: CRM Phase 2 - Sponsor Contract Signing & Automation

Related: #199