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JSON API to DOCX for invoices: 13 document generation tools

For invoices, we list 13 tools that turn JSON sent to an API into a Word document. The lowest paid starting price is $19 a month, from SourceToDocs. The first three in our order are Conga Composer, Carbone and Fluent (Windward).

Tools
13
With USD price
8, from $19
Free tier
8
Direct / via Zapier
10 / 3
Checked
20 Oct 2026
  1. 01
    Conga Composer Editor's pick conga.com

    Enterprise Salesforce document generation.

    Outputs PDF, DOCX, XLSX, PPTX, HTML, email Template Word Also reads Salesforce G2 4.4 (849)
    Not published
  2. 02
    Carbone Editor's pick carbone.io

    Priced in EUR: Essential EUR 29/mo (EUR 26 annual).

    Outputs PDF, DOCX, XLSX, PPTX, HTML Template Word Also reads Airtable, Zapier/Make/n8n
    $28 EUR 26, converted
  3. 03
    Fluent (Windward) windwardstudios.com

    Formerly Windward Studios, acquired by PDFTron (now Apryse).

    Outputs PDF, DOCX, XLSX, PPTX, HTML Template Word Also reads Salesforce, Excel G2 4.4 (77)
    On request
  4. 04
    SourceToDocs sourcetodocs.com

    Data to Google Slides and Docs.

    Outputs Google Slides, Google Docs, PDF, PPTX, DOCX, HTML Template Google Docs Also reads Airtable, Google Sheets, CSV
    $19 / mo, cheapest here
  5. 05
    Syncfusion Document SDK syncfusion.com

    $1,199/developer/yr (computed $99.92/mo).

    Outputs PDF, DOCX, XLSX, PPTX Template Word
    $99.92 / mo
  6. 06
    Docmosis docmosis.com

    Cloud Professional $49/mo, 4,000+ pages.

    Outputs PDF, DOCX, HTML Template Word
    $49 / mo
  7. 07
    Foxit Document Generation API developer-api.foxit.com

    Word template plus JSON. Startup $1,750/yr (computed $145.83/mo).

    Outputs PDF, DOCX Template Word
    $145.83 / mo
  8. 08
    Experlogix Document Automation experlogix.com

    Also Dynamics 365, SugarCRM, Power Platform.

    Outputs PDF, DOCX, XLSX, email, e-sign documents Template Word Also reads Salesforce
    On request
  9. 09
    jsreport jsreport.net

    Free up to 5 templates. Enterprise $395/yr single instance.

    Outputs PDF, DOCX, XLSX, PPTX, HTML Template HTML
    On request free tier
  10. 10
    PDF4me pdf4me.com

    Ynoox GmbH. Generate Documents endpoint.

    Outputs PDF, DOCX Template Word Also reads Zapier/Make/n8n
    Not published free tier
  11. 11
    Docupilot Editor's pick via Zapier docupilot.com

    Starter $29/mo, 100 docs.

    Outputs PDF, DOCX, PPTX, XLSX, e-sign documents Template Word, Visual builder Also reads Airtable, Zapier/Make/n8n, built-in forms
    $29 / mo
  12. 12
    Documentero via Zapier documentero.com

    Micro $19.50/mo shown; price formatting unclear on page.

    Outputs DOCX, XLSX, PDF Template Word Also reads Google Sheets, CSV, Excel, Zapier/Make/n8n +1
    $19.50 / mo
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  1. 13
    DocuGenerate via Zapier docugenerate.com

    Word templates plus JSON.

    Outputs PDF, DOCX Template Word Also reads Coda, Zapier/Make/n8n
    $19 / mo

What differs for JSON API

For invoices delivered as DOCX, templates are built in Word (11), Google Docs (1) and HTML (1). Among them, 3 need Zapier, Make or n8n to read JSON sent to an API, so they sit after the tools with a direct connection. Of these, 8 have a free tier.

Besides DOCX, these tools for invoices also write PDF (13), XLSX (8) and PPTX (7). Your own code decides when to call the API, so a document can be built on any event. Published starting prices run from $19 to $145.83 a month, the top end from Foxit Document Generation API. Prices were checked on 20 Oct 2026.

Nearby pages

Broader list: JSON API to DOCX (29 tools).

Related lists: JSON API to DOCX for contracts (22 tools), JSON API to DOCX for letters (15), JSON API to DOCX for reports (15), JSON API to DOCX for proposals (7), JSON API to PDF for invoices (35), JSON API to XLSX for invoices (9), JSON API to PPTX for invoices (7), JSON API to HTML for invoices (6).

How to generate PDFs from a JSON API: a step-by-step guide, updated 21 Oct 2026.

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