Chapter 30: XML Applications
1. What do we mean by “XML Applications”?
When we talk about XML applications, we mean:
Real-world systems, formats, standards, file types, protocols, or use-cases that use XML as their main (or very important) data format.
Not just “XML is a markup language” — but where and why actual companies, governments, banks, publishers, software products still choose XML instead of JSON, YAML, CSV, etc.
2. The honest current status (2025–2026)
| Statement | Reality in 2025–2026 |
|---|---|
| “XML is dead” | False — JSON won new web APIs, but XML is very alive in many important domains |
| “Nobody uses XML anymore” | False — millions of transactions every day still use XML |
| “XML is only legacy” | Partially true — new greenfield projects rarely start with XML, but huge legacy & regulated systems continue |
| “XML is only used because of inertia” | Partially true — but also because of very strong reasons in many industries |
3. The most important real XML applications today
I will list them roughly in order of how much real volume / money / regulation still flows through them.
1. Electronic Invoicing & Business Documents (biggest current use)
Examples of standards/formats:
- UBL (Universal Business Language) → basis for PEPPOL, many national e-invoice systems
- India GST e-Invoice (very large volume — mandatory for B2B > ₹5 crore turnover)
- Factura Electrónica (Mexico, Colombia, Chile, Peru…)
- ZUGFeRD / Factur-X (Europe – hybrid PDF+XML)
- Cross Industry Invoice (CII) (France)
- XRechnung (Germany public sector)
Typical XML size: 5–50 KB per invoice Daily volume: India alone → tens of millions of e-invoices per month
Very simplified real fragment (India GST format – heavily namespaced)
XML
|
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 |
<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2"> <cbc:ID>INV/2025/0789</cbc:ID> <cbc:IssueDate>2025-07-28</cbc:IssueDate> <cbc:InvoiceTypeCode name="Tax Invoice">INV</cbc:InvoiceTypeCode> <cac:AccountingSupplierParty> <cac:Party> <cbc:Name>TechTrend Innovations Pvt Ltd</cbc:Name> <cac:PartyIdentification> <cbc:ID schemeID="GSTIN">36AAECT4567P1Z2</cbc:ID> </cac:PartyIdentification> </cac:Party> </cac:AccountingSupplierParty> <cac:TaxTotal> <cbc:TaxAmount currencyID="INR">41400.00</cbc:TaxAmount> </cac:TaxTotal> <cbc:PayableAmount currencyID="INR">271400.00</cbc:PayableAmount> </Invoice> |
2. Financial Messaging & Payments
Standards still heavily XML-based:
- ISO 20022 (payment initiation, statements, camt.053, pacs.008…)
- FIXML (Financial Information eXchange – trading)
- FpML (Financial products Markup Language – derivatives)
- SEPA (some XML parts)
- SWIFT (many legacy messages still XML-wrapped)
Typical use: Banks, payment gateways, treasury systems, clearing houses
3. Healthcare & Clinical Documents
Main formats:
- HL7 CDA (Clinical Document Architecture) → discharge summaries, lab reports, referrals
- FHIR XML (less common than JSON, but still supported and used)
- DICOM SR (structured reports)
Very large hospitals, labs, insurance companies, government health portals still exchange millions of CDA documents.
4. Publishing, Technical Documentation & Office Formats
Still very active areas:
- DocBook → books, manuals, technical documentation
- DITA (Darwin Information Typing Architecture) → IBM, Boeing, many defense/aerospace companies
- JATS (Journal Article Tag Suite) → scientific publishing (PubMed, IEEE…)
- Office Open XML (.docx, .xlsx, .pptx) — ZIP + lots of XML files
- IDML (InDesign Markup Language)
Thousands of companies still produce and exchange technical manuals, legal documents, books in XML.
5. Legacy Enterprise & Government Integration
Typical places you still meet XML every day:
- SOAP web services (many banks, insurance, government portals)
- ERP ↔ ERP integration (SAP IDocs often XML-wrapped)
- Customs / trade documents (many countries still use XML-based declarations)
- Configuration files in older Java EE / Spring / .NET systems
4. Quick Summary Table – Most Important XML Applications in 2025–2026
| Domain | Main XML formats / standards | Volume / Importance today | JSON alternative? | Migration status |
|---|---|---|---|---|
| e-Invoicing / B2B documents | UBL, GST e-Invoice, Factur-X, XRechnung | Extremely high | Partial | Slow |
| Financial messaging | ISO 20022, FIXML, FpML | Very high | Partial | Ongoing |
| Healthcare | HL7 CDA, FHIR XML | High | FHIR JSON dominant | In progress |
| Publishing / documentation | DocBook, DITA, JATS | Medium–High | Rare | Slow |
| Office documents | OOXML (.docx, .xlsx, .pptx) | Extremely high | No | Stable |
| Legacy SOAP services | SOAP + custom XML payloads | High in enterprise | REST/JSON | Slow |
| Configuration files | web.xml, Spring XML, Maven pom.xml | Medium | YAML/JSON | Gradual |
5. Realistic small example – e-Invoice fragment (very common today)
XML
|
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 |
<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2"> <cbc:ID>INV/2025/0789</cbc:ID> <cbc:IssueDate>2025-07-28</cbc:IssueDate> <cac:AccountingSupplierParty> <cac:Party> <cbc:Name>TechTrend Innovations Pvt Ltd</cbc:Name> <cac:PartyIdentification> <cbc:ID schemeID="GSTIN">36AAECT4567P1Z2</cbc:ID> </cac:PartyIdentification> </cac:Party> </cac:AccountingSupplierParty> <cac:TaxTotal> <cbc:TaxAmount currencyID="INR">41400.00</cbc:TaxAmount> </cac:TaxTotal> <cbc:PayableAmount currencyID="INR">271400.00</cbc:PayableAmount> </Invoice> |
This kind of XML is processed millions of times every day in countries with mandatory e-invoicing.
Final realistic advice (2025–2026)
If you are:
- Building a new consumer web/mobile app → use JSON
- Working in finance, insurance, healthcare, government, logistics, manufacturing → learn XML very well — you will meet it a lot
- Maintaining legacy systems → XML is probably central
- Dealing with large batch files (invoices, statements, catalogs) → XML is still very common
Would you like to go deeper into any of these real XML applications?
- Full GST e-Invoice structure + validation
- ISO 20022 payment message example
- HL7 CDA clinical document fragment
- Office Open XML inside a .docx file
- How modern systems transform XML → JSON when needed
- Why some industries refuse to move away from XML
Just tell me which direction feels most interesting or useful for you right now! 😊
