Carbone alternative: invoices without template files
Carbone's pitch is elegant: design templates in the tools your team already knows (Word, Excel, LibreOffice), then inject JSON and export to PDF, DOCX, XLSX, and more. It is a strong general-purpose document generator with an open-source core. Slipstack attacks a narrower problem: invoices and receipts, where the layout is solved, so even a Word template is one artifact too many. Here is where each approach wins.
Side by side, as of June 2026
Features and pricing below were checked against carbone.io/pricing.html in June 2026. Carbone's public table lists prices but not per-plan document counts, so we note that rather than guess. Always confirm current numbers on their site.
| Carbone | Slipstack | |
|---|---|---|
| Template model | Real documents: DOCX, ODT, XLSX, PPTX, HTML, Markdown, IDML | None. Built-in invoice and receipt layouts |
| Output formats | PDF, DOCX, XLSX, PPTX, ODS, HTML, CSV | PDF only |
| Self-hosting | Yes: open-source Community edition; on-premise from $1,500/yr | No, hosted API only |
| Free tier | Free cloud plan available | 50 documents/month, no card |
| Cloud pricing | $29/mo (Essential) to $595/mo (Ultra); per-plan document counts not shown on the public pricing page | $19 for 1,000, $49 for 5,000, $199 for 50,000 docs/mo |
| Document definition | One render with data (JSON + images) under 1 MB | One generated PDF |
| Totals, tax, discounts | Computed in template formulas or your code | Computed by the API from line items |
| Who owns the layout | Whoever edits the Word/Excel template | Slipstack; you pass logo and accent color |
| Agent integration | None documented | Remote MCP server at /api/mcp |
When Carbone is the better choice
- Business users own the templates. If finance edits the invoice layout in Word and ships it without a deploy, Carbone's model is exactly right. That is their core promise: separate design from data.
- You need more than PDF. Generating the same report as PDF for email and XLSX for analysts is something Slipstack simply cannot do.
- Self-hosting is a requirement. Carbone has an open-source Community edition and on-premise licenses. For air-gapped or data-residency-bound environments, that settles it.
- You generate many document types. Contracts, packing lists, certificates, reports: one engine, one skill set, every document.
When Slipstack fits better
- You only need invoices and receipts. Then a template, even a friendly Word one, is an artifact to version, review, and break. Slipstack removes it: JSON in, branded PDF out, synchronously.
- You want arithmetic guarantees. Slipstack computes subtotals, discounts, and tax server-side from line items. No formula in a template to get wrong.
- Published, predictable quotas. Every Slipstack plan states its document count on the pricing page, starting with a free 50 documents/month.
- Agents are part of your workflow. The Slipstack MCP server makes invoice generation a native tool for Claude and other MCP clients. The AI agents guide has the setup.
FAQ
What is the core difference between Carbone and Slipstack?
Carbone merges your JSON data into templates you design in real document tools (Word, LibreOffice, Excel, PowerPoint, even InDesign IDML) and can output PDF, DOCX, XLSX, and more. Slipstack has no templates at all: it accepts invoice or receipt JSON and renders a finished PDF with a built-in professional layout. Carbone is a general document generator; Slipstack is a purpose-built invoice and receipt API.
Is Carbone cheaper?
It depends on volume and plan. As of June 2026 Carbone Cloud lists a free plan and paid plans from $29/month (Essential) up to $595/month (Ultra), but the public pricing table does not display per-plan document counts, so a per-document comparison is not possible from their site alone. Slipstack publishes its quotas: free 50 documents/month, $19 for 1,000, $49 for 5,000, $199 for 50,000.
Can I self-host Slipstack like Carbone?
No. Carbone offers an open-source Community edition and on-premise licenses (listed from $1,500/year as of June 2026), which is a real advantage if self-hosting is a requirement. Slipstack is a hosted API only.
Does Slipstack output DOCX or XLSX?
No, PDF only. Carbone can generate PDF, DOCX, XLSX, PPTX, ODS, HTML, and CSV from the same template. If you need editable office formats, choose Carbone.
Which one works with AI agents?
Slipstack ships a remote MCP server, so Claude, Claude Code, Cursor, and any MCP client can generate invoice PDFs as a native tool, with a 10 documents/day demo quota that needs no signup. Carbone does not document an MCP integration as of June 2026.
No template files. Ever.
Free tier: 50 documents a month, no card. Try the no-signup generator to see the layout.
Related reading
- PDF Generator API alternative for another template-editor comparison.
- DocRaptor alternative if you are weighing HTML-to-PDF engines.
- Receipt API guide for the receipt side of the same JSON schema.