Xml Viewer.app VS xmlvalid

Xml Viewer.app's answer

Choose XML-Viewer.app when you need to quickly read an XML invoice or inspect an XML file without installing software. It provides readable invoice layouts alongside XML viewing and formatting, with document processing kept on your device. It is a focused option for users who need to view documents without adopting a full invoicing or accounting system.

xmlvalid's answer:

• Desktop editors (XMLSpy, Oxygen) are powerful but expensive and need installing; xmlvalid works in the browser for free
• Simple online validators check one schema and stop at a few MB; xmlvalid streams up to 1 GB and ships schemas with all their imports
• E-invoice validators (KoSIT, Peppol testbeds) check one format each and have no CI tooling; xmlvalid covers many formats and countries, reads PDF invoices, and has an API, CLI and GitHub Action
• Documents are validated in the browser and not uploaded

Xml Viewer.app's answer

XML-Viewer.app combines a general-purpose XML viewer with electronic invoice rendering. Supported XML invoices are displayed as readable documents with supplier and customer details, line items, taxes and totals. Users can switch to the XML source to inspect the underlying data. All parsing and rendering happens locally in the browser, without uploading document contents to a server.

xmlvalid's answer:

• Schema validation and e-invoicing business rules in one place: XSD, DTD and RelaxNG, plus 7,700+ Schematron rules of EN 16931, Peppol BIS and PINT, XRechnung, Factur-X and national formats from France and Italy to Saudi Arabia, Mexico and Brazil
• Built for large files: a streaming Rust engine (libxml2 compiled to WebAssembly) validates documents up to 1 GB in the browser with flat memory (5 GB tested)
• 177 official schemas ready to use, and e-invoice profiles detected automatically from the document
• E-invoice PDFs (Factur-X, ZUGFeRD, ISDOC) checked whole: the XML inside, PDF/A, and the PDF's text against the XML
• Every error links to a page explaining why it fails and how to fix it, for libxml2, Java and .NET messages
• The same checks in CI and integrations: REST API, SOAP, MCP server for AI agents, CLI, GitHub Action, n8n

Xml Viewer.app's answer

People who receive electronic invoices as XML files and need to read their contents, including small business owners, accountants and finance teams. It also serves developers and integration specialists who need to inspect and format XML or compare an invoice's readable view with its source data.

xmlvalid's answer:

• Developers and integrators building or receiving e-invoices (Peppol, XRechnung, Factur-X, FatturaPA, KSeF, ZATCA, CFDI, NF-e, UBL, CII)
• ERP and accounting software vendors preparing for national e-invoicing mandates
• Teams that exchange XML with partners: payments (ISO 20022), healthcare (HL7 CDA, FHIR), feeds and sitemaps
• DevOps engineers who want XML checks in CI pipelines
• Anyone who needs to validate a large XML file quickly without installing software

Xml Viewer.app's answer

XML-Viewer.app was built around a simple goal: make XML useful to the person opening it. For developers, that means clear formatting and convenient inspection. For someone receiving an electronic invoice, it means seeing a readable invoice rather than a page of XML tags. The project brings both workflows together in a browser-based application that processes documents locally.

xmlvalid's answer:

xmlvalid is built and run by Oleksii Babintsev, a developer from Ukraine, so questions and bug reports reach the person who builds the engine. It started as a streaming validator for XML files too large for typical online tools, and grew into e-invoicing as countries made structured invoices mandatory: business rules for EN 16931, Peppol, XRechnung and national formats in 24 countries, PDF invoices, an API, CLI and GitHub Action for CI, and monitors for XML feeds. While building it, we found and fixed a slowdown in libxml2's validation of large files and contributed the fix upstream. It launched in October 2026

Xml Viewer.app's answer

Next.js and React for the web application, with client-side XML parsing and document rendering. XML files are processed in the user's browser.

xmlvalid's answer:

• Rust and libxml2 (validation engine), compiled to WebAssembly
• SaxonJS (Schematron business rules)
• veraPDF (PDF/A checks)
• Laravel and Livewire (PHP)
• Tailwind CSS
• PostgreSQL, Redis, Meilisearch
• Cloudflare

Xml Viewer.app's answer

XML-Viewer.app has recently launched and does not yet have publicly announced customer references.