Last verified: July 2026. Yes, we're on this list; we've marked where and kept everyone's numbers sourced so you can check our work.
Every comparison of e-invoicing APIs makes the same mistake: it lists Peppol access points and document-generation APIs side by side as if they were interchangeable. They aren't. One moves invoices between systems; the other builds and checks the invoices themselves. Plenty of teams need only one of the two — and some need both, composed. So this guide is organized the way the decision actually works.
First, know which problem you have
You need the document layer if your software produces invoices and a mandate (or a customer) now requires them in EN 16931 XML — XRechnung for Germany, Factur-X for France, Peppol BIS 3.0 for the network. The work is data mapping, VAT arithmetic that survives 190+ business rules, and validation with errors a developer can act on. Note: for the German mandate, e-mail delivery of XRechnung is standard practice — no network subscription required at all.
You need the network layer if your invoices must travel over Peppol (Belgium's B2B mandate, public-sector buyers across Europe): registration, certified access point, transport acknowledgments.
Document-layer APIs (generate, convert, validate)
faktur/wire (this site) — validate and convert: JSON or UBL in, compliant Peppol BIS 3.0 / XRechnung / Factur-X out; conversion refuses non-compliant invoices with the full findings list instead of shipping a document your customer's tax office will bounce. Pay-per-use credits that never expire: validation from €0.02, conversion ~€0.05/invoice at the €49 tier. 50 free credits on signup, free validator without signup. No Peppol transport (pair with an access point below). Best for: platforms and dev teams that want compliance checked before delivery, without a subscription.
thelawin.dev — JSON to hybrid PDF/A-3 with embedded XML, 9 formats, €0.049 per call or plans from €9.50/mo, free validation, 8 SDKs. Best for: teams whose primary output is the human-readable hybrid PDF.
invoice-api.xhub.io — XRechnung 3.0.2 / ZUGFeRD 2.4 generation with KoSIT Schematron validation; €18/mo for 2,000 calls, €62/mo for 20,000. Best for: German-market subscriptions at steady volume.
InvoiceXML — create/validate/convert across the format spectrum plus AI extraction from messy PDFs; from ~$15/mo. Best for: mixed workloads including legacy-PDF intake.
Mustangproject — the open-source Java baseline (ZUGFeRD/Factur-X/XRechnung tooling and validator). Free forever, no service behind it: you own updates, rule changes and edge cases. Best for: JVM shops with engineering time to invest.
Network-layer APIs (Peppol access points)
e-invoice.be — €0.18–0.25 per invoice, no monthly fee (€350 minimum credit purchase; send and receive billed separately). Outstanding docs and SDKs. Best for: developer teams hitting the Belgian mandate.
Recommand — the most transparent pricing in the category: free ≤25 docs/mo, €29/mo for 200, up to €349/mo for 5,000 (inbound + outbound both count). Best for: Belgian SMEs and small platforms.
peppol.sh — €0.10–0.20 per sent invoice, no minimums, non-expiring credits, sandbox-first onboarding. Best for: developers who want Stripe-style self-serve.
Storecove — the incumbent: Peppol plus 30+ national frameworks (SDI, KSeF, ANAF…) in one API. No public pricing; third-party estimates range €99–495+/month. Best for: multi-country platforms that genuinely need many networks — see our detailed comparison.
Enterprise suites — ecosio, Pagero, EDICOM, Basware: full managed compliance, contact-sales pricing, implementation projects. Best for: enterprises with EDI teams.
What it actually costs at your volume
Effective cost per invoice, computed from published prices (document generation + validation on the left; Peppol delivery on the right):
| Monthly volume | Document layer (faktur/wire, Growth pack) | Peppol delivery (cheapest published) |
|---|---|---|
| 100 | ~€7 (€0.07/inv incl. validation) | €10–25 |
| 1,000 | ~€61 (€0.06/inv) | €99–250 |
| 10,000 | ~€430 (Scale pack, €0.04/inv) | €700–1,800 |
Two patterns worth noticing. First, the subscription trap at low volume: below ~200 invoices/month, any monthly fee dominates your per-invoice cost — this is where non-expiring credit models win outright. Second, the meter matters: some providers count inbound documents, some bill send and receive separately, some expire unused volume monthly. Read the meter definition before comparing headline prices.
A 2026 footnote: AI-agent readiness
A quiet differentiator this year: several providers (e-invoice.be, Invoicetronic, thelawin.dev, xhub — and yes, we're building ours) now ship MCP servers or agent-friendly APIs, so AI coding assistants can integrate e-invoicing without a human reading the docs. If your integration will be written by Claude or Copilot — increasingly likely — check for an OpenAPI spec and structured, machine-actionable error responses. It's also a decent proxy for overall API quality.
The short version
Germany-only mandate → document layer only; you may not need a network subscription at all. Belgian mandate → network layer; e-invoice.be, Recommand or peppol.sh depending on volume. Building a platform → compose a document API with an access point, and insist on published pricing for both. Enterprise, many countries, procurement department → Storecove or the suites, and negotiate.
Try the document layer in the next five minutes: validate an invoice free, or get an API key with 50 free credits — no card, no call.