# Organized Archiving System for E‑Invoice and E‑Archive PDFs
In Turkey, businesses must store e‑invoice and e‑archive documents for 10 years (Tax Procedure Law Article 23). During this period the files must be findable, readable, and unalterable. Below is a 7‑step practical guide to meet this obligation efficiently.
1. Create an Archiving Policy
- Define Legal Retention Periods – e‑invoice and e‑archive PDFs: 10 years; VAT documents: 5 years (see table).
- Define Access Rights – Clearly state which departments (accounting, audit, management) may access the files.
- Set Security Standards – Include encryption (AES‑256), two‑factor authentication (2FA), and regular backups (daily, weekly).
2. File‑Naming Convention
Standardizing file names reduces search time by up to 70 %. Recommended format:
```
YYYYMMDD_CompanyCode_InvoiceNo_Type.pdf
```
* YYYYMMDD – Date (2024‑09‑15)
* CompanyCode – 3‑letter code (ABC)
* InvoiceNo – 7‑digit number (0001234)
* Type – INV (e‑invoice) / ARCH (e‑archive)
> Example: `20240915_ABC_0001234_INV.pdf`
3. Folder Structure
The hierarchy below, organized by year and month, easily handles 10,000+ files.
```
Root /
│
├─ 2024 /
│ ├─ 01 (January) /
│ │ ├─ INV /
│ │ └─ ARCH /
│ └─ 02 (February) /
│ ├─ INV /
│ └─ ARCH /
⋮
└─ 2025 /
└─ …
```
4. Automated Transfer & Verification
- API Integration – Push PDFs from your ERP or invoicing system directly into the folder.
- Hash Check – Generate a SHA‑256 hash for each file; after transfer, compare hashes to verify integrity.
- Logging – Store a `log.txt` with timestamp, user, and file name for every operation.
5. Backup Strategy
| Layer | Frequency | Storage Type | Retention |
|---|---|---|---|
| Daily | Every 24 h | Local NAS | 30 days |
| Weekly | Once a week | Cloud (AWS S3) | 6 months |
| Monthly | Once a month | Off‑site (cold) | 10 years |
- **Total Storage Cost**: Approx. **USD 1,200** per year for 5 TB.
- **Recovery Time Objective (RTO)**: Maximum **12 hours** (monthly layer).
6. Search & Export Module
Create a lightweight SQLite database that indexes date, invoice number, company code, and type. Sample query:
```sql
SELECT file_path FROM invoices
WHERE invoice_date BETWEEN '2024-01-01' AND '2024-12-31'
AND company_code = 'ABC'
AND type = 'INV';
```
The query lists all 2024 e‑invoices for ABC in seconds.
7. Periodic Audits & Reporting
- Monthly – Verify folder structure and naming compliance.
- Quarterly – Review backup logs; keep failed‑backup rate below 0.5 %.
- Yearly – Independent auditor checks data integrity (hash comparison) and access permissions.
Sample Audit Report
| Audit Date | Issue Found | Resolution Time | Notes |
|---|---|---|---|
| 2024‑03‑15 | 2 files missing hash | 2 hours | Auto‑fix script executed |
| 2024‑09‑20 | Backup delay (24 h) | 1 hour | Server time sync corrected |
Real‑World Example: “TeknoSoft” Company
TeknoSoft began generating 150,000 e‑invoice PDFs in 2022. After implementing the system, performance metrics improved as shown below.
| Before (Manual) | After (Automated) |
|---|---|
| Avg. search time: **3 minutes** | Avg. search time: **8 seconds** |
| Backup error rate: **4.2 %** | Backup error rate: **0.1 %** |
| Employee satisfaction: **6/10** | Employee satisfaction: **9/10** |
These results translate to an annual USD 45,000 cost saving and a 98 % reduction in data‑loss risk.
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Summary
- Policy – Define legal, security, and retention rules.
- Naming – Automate a standard filename format.
- Folder – Use year‑month‑type hierarchy for easy navigation.
- Transfer – Secure API, hash, and logging ensure integrity.
- Backup – Three‑layer strategy keeps RTO under 12 hours.
- Search – SQLite + indexed queries retrieve files in seconds.
- Audit – Regular checks maintain compliance.
By following these steps, you can archive e‑invoice and e‑archive PDFs legally, securely, and efficiently, delivering flawless performance during internal and external audits.
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*This guide reflects the legislation and technology standards applicable as of 2024.*