# Document Processing

> Convert, merge, append and analyze documents over HTTP with the DocumentProcessing Web API: access tokens, Base64 JSON bodies, curl and .NET, PDF and barcodes.

- **Product:** DS Server
- **Section:** Documentation
- **Kind:** Topic
- **Path:** DS Server > Document Processing
- **Web URL:** https://docs.textcontrol.com/ds-server/document-processing/
- **LLMs URL:** https://docs.textcontrol.com/ds-server/document-processing/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/ds-server/document-processing/llms-full.txt

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## On This Page

- [How a Request Looks](https://docs.textcontrol.com/ds-server/document-processing/#how-a-request-looks)
- [Find the Right Page](https://docs.textcontrol.com/ds-server/document-processing/#find-the-right-page)
- [Where to Start](https://docs.textcontrol.com/ds-server/document-processing/#where-to-start)
- [Pages in This Section](https://docs.textcontrol.com/ds-server/document-processing/#pages-in-this-section)

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## In This Section

- [Appending Documents](https://docs.textcontrol.com/ds-server/document-processing/appending/llms.txt): Put a cover letter in front of an invoice or join reports into one PDF with the append endpoint: AppendDocument, section dividers and document properties.
- [Authentication](https://docs.textcontrol.com/ds-server/document-processing/authentication/llms.txt): Request an OAuth access token at /oauth/token with the client credentials or authorization code grant, send it as a Bearer header and renew it in curl or .NET.
- [Barcodes](https://docs.textcontrol.com/ds-server/document-processing/barcodes/llms.txt): Generate QR code, Code 128 or Data Matrix images in curl or .NET with barcodes/create: size, colors and text, plus length and validity checks of the text first.
- [Converting Documents](https://docs.textcontrol.com/ds-server/document-processing/converting/llms.txt): Convert DOCX, RTF, HTML and PDF to PDF, PDF/A, DOCX, DOC, RTF, HTML, TX or plain text with the convert endpoint and flatten form fields, from curl or .NET.
- [Document Information](https://docs.textcontrol.com/ds-server/document-processing/document-info/llms.txt): Check a template before a merge: read its merge fields, nested merge blocks and properties with the info endpoint or DocumentInfo, and list server printers.
- [Errors and Status Codes](https://docs.textcontrol.com/ds-server/document-processing/errors/llms.txt): Handle 400, 401, 404, 405 and 415 answers of the DocumentProcessing Web API: not registered, validation and token errors, and ServiceRequestException in .NET.
- [Find and Replace](https://docs.textcontrol.com/ds-server/document-processing/find-replace/llms.txt): Replace text placeholders such as %%CustomerName%% in DOCX, DOC or RTF documents with the findandreplace endpoint and FindAndReplaceBody instead of a merge.
- [Merging Templates](https://docs.textcontrol.com/ds-server/document-processing/mail-merge/llms.txt): Merge DOCX templates with JSON data into invoices and letters with the merge endpoint: merge fields, merge blocks, one document per record and MergeSettings.
- [PDF Form Fields](https://docs.textcontrol.com/ds-server/document-processing/pdf-forms/llms.txt): Extract the values of text boxes, check boxes and combo boxes from the AcroForm fields of a PDF form with pdf/acroforms/fields or GetFields, and flatten fields.
- [PDF Documents](https://docs.textcontrol.com/ds-server/document-processing/pdf/llms.txt): Create PDF and PDF/A-3b with pdf/create: properties, passwords, access permissions, digital signatures and attachments; read PDF metadata and embedded files.
- [Thumbnails](https://docs.textcontrol.com/ds-server/document-processing/thumbnails/llms.txt): Create page previews of DOCX and PDF files as PNG, JPG or SVG images with the thumbnails endpoint in curl or .NET: zoom factor, page range and SVG on Linux.

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## Nearby

- **Previous:** [React](https://docs.textcontrol.com/ds-server/client-libraries/react/llms.txt)
- **Next:** [Authentication](https://docs.textcontrol.com/ds-server/document-processing/authentication/llms.txt)