Tw Einvoice Guide

B2B vs B2C Invoice Differences

Carrier Types (載具)

Implementation Steps

Phase 1: Registration

1. Register on 財政部電子發票整合服務平台
2. Apply for 加值服務中心 AppID (if using API method)
3. Set up certificate and authentication

Phase 2: Development/Integration 4. Choose integration method (Turnkey vs API vs POS) 5. Implement invoice issuance: create, void, void-and-reissue 6. Implement carrier scanning (手機條碼 barcode) 7. Handle 捐贈碼 (donation codes)

Phase 3: Testing 8. Test in sandbox environment 9. Issue test invoices, verify on MOF platform 10. Test void/reissue flows

Phase 4: Go-Live 11. Switch to production environment 12. Monitor daily: match issued invoices vs MOF records 13. Bimonthly: reconcile with 營業稅 filing (401 form)

Common API Flows

Issue Invoice:

POST /invoice → { seller_id, buyer_id (optional), items[], amount, tax, carrier_type, carrier_id }
→ Response: { invoice_number, invoice_date, random_code }

Void Invoice:

POST /invoice/void → { invoice_number, invoice_date, void_reason }

Query Invoice:

GET /invoice/{number} → { status, items, amount, carrier }

Output Format

# E-Invoice Implementation Plan: {Business}

## Current State
- Business type: B2B / B2C / Both
- Current invoicing: Paper / Partial e-invoice / None
- Transaction volume: {N}/month

## Integration Method
- Method: {Turnkey / API / POS integration}
- Provider: {加值中心 name, if applicable}
- Rationale: {why this method}

## Implementation Checklist
- [ ] MOF platform registration
- [ ] AppID obtained
- [ ] Integration developed
- [ ] Sandbox testing passed
- [ ] Carrier scanning implemented
- [ ] Donation code support
- [ ] Production go-live
- [ ] Reconciliation process documented

## Timeline
| Phase | Duration | Milestone |
|-------|----------|-----------|
| Registration | 1-2 weeks | AppID obtained |
| Development | 2-4 weeks | Integration complete |
| Testing | 1-2 weeks | Sandbox verified |
| Go-live | 1 day | First production invoice |

Gotchas

• Invoice number format is assigned by MOF: You don't generate invoice numbers. The MOF assigns number ranges (字軌) that you request in advance. Run out of numbers = can't issue invoices. Request well ahead of time.
• Void window is limited: Invoices can be voided within the same bimonthly period. After the period closes, voiding requires a more complex process (折讓).
• 手機條碼 scanning: The barcode is a slash + 7 characters. Many POS scanners need configuration to read this format correctly. Test with real 手機條碼 barcodes.
• Prize drawing (中獎): B2C e-invoices are automatically entered into the government lottery (統一發票兌獎). Your system must support winner notification if the invoice was stored in a membership carrier.
• Reconciliation is critical: The MOF platform is the source of truth. If your system's invoice records don't match the platform, your 營業稅 filing will have discrepancies. Reconcile daily.

References

• For 加值服務中心 API documentation, see references/einvoice-api.md
• For 營業稅 filing reconciliation, see the tw-tax-basics skill