DocGen Guide 128 tools · prices checked 20 Oct 2026 Find my tool
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Proposal generators for JSON API

If you need a proposal built from JSON sent to an API, 11 tools here can make one. The first three in our order are Conga Composer, Formstack Documents and Documint. Of these, 4 have a free tier.

Tools
11
With USD price
8, from $19
Free tier
4
Direct / via Zapier
10 / 1
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
    Formstack Documents Editor's pick formstack.com

    Formerly WebMerge. Only in Suite plan, $250/mo paid annually, 250 deliveries/mo.

    Outputs PDF, DOCX, PPTX, e-sign documents Template Word, PDF form, Visual builder Also reads Salesforce, HubSpot, Airtable, built-in forms +2 G2 4.5 (148)
    $250 / mo
  3. 03
    Documint Editor's pick documint.me

    Silver $39/mo billed annually.

    Outputs PDF, e-sign documents Template Visual builder Also reads Airtable, HubSpot, Coda, Zapier/Make/n8n G2 4.7 (9)
    $39 / mo
  4. 04
    DocsAutomator Editor's pick docsautomator.co

    Professional $19/mo yearly, $29 monthly.

    Outputs PDF, Google Docs, email Template Google Docs, Word, PDF form Also reads Airtable, Notion, Google Sheets, Google Forms +2
    $19 / mo, cheapest here
  5. 05
    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
  6. 06
    Templafy templafy.com

    AI document agents in Microsoft Office.

    Outputs PPTX, DOCX, PDF Template Word Also reads Salesforce
    $40 / mo
  7. 07
    DoxFlowy doxflowy.com

    Core $20/user/mo annual per Capterra.

    Outputs PDF, e-sign documents Template Visual builder Also reads built-in forms
    $20 / mo
  8. 08
    Gamma gamma.app

    AI presentations. Exports PPTX, PDF, Google Slides on Free.

    Outputs PPTX, PDF, Google Slides Template Visual builder Also reads HubSpot
    Not published free tier
  9. 09
    ActiveDocs activedocs.com

    Word-based enterprise document generation.

    Outputs DOCX, PDF, e-sign documents Template Word
    On request
  10. 10
    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
  11. 11
    PandaDoc Editor's pick pandadoc.com

    Adjacent proposal and e-sign suite.

    Outputs PDF, e-sign documents, DOCX Template Visual builder Also reads HubSpot, Salesforce, Pipedrive, Zapier/Make/n8n G2 4.7 (3324)
    $19 / mo

What differs for JSON API

For proposals built from JSON sent to an API, the lowest paid starting price is $19 a month, from DocsAutomator. Published starting prices run from $19 to $250 a month, the top end from Formstack Documents.

These tools for proposals most often write PDF (11), DOCX (7) and PPTX (6). Among them, 1 needs Zapier, Make or n8n to read JSON sent to an API, so it sits after the tools with a direct connection. Your own code decides when to call the API, so a document can be built on any event. Prices were checked on 20 Oct 2026.

Not sure which one fits? Answer three questions and get three tools back, scored by the rules on the methodology page.

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