FB2 to OTT Converter

Convert FB2 to OTT online for free. Fast, secure, and high-quality conversion with no sign-up or software required.

Free to useNo file stored beyond 1 hourEncrypted over TLS 1.2/1.3No watermarks

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Maximum file size is 1GB

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How it works

Three steps to your converted file

Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.

Upload your file

Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.

Choose an output format

Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.

Convert & download

Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.

What is an FB2 file?

FB2 (FictionBook) is an XML-based e-book format originally developed in Russia by Dmitry Gribov. Unlike ZIP-based containers like EPUB, an FB2 file is a single monolithic XML document where the text is marked up with semantic tags describing the structure (epigraphs, verses, citations) rather than the visual appearance. Binary data, such as cover images or illustrations, are embedded directly within the XML file using Base64 encoding. This structural focus facilitates easy conversion to other formats and precise rendering across different hardware devices.

How to open an FB2 file

Support for FB2 is prevalent in e-reading software but rare in native OS environments. Calibre is the primary tool for opening and converting FB2 files on Windows, macOS, and Linux. For dedicated reading, FBReader and CoolReader are cross-platform applications specifically optimized for parsing the FictionBook XML schema. Android users frequently use Moon+ Reader, while iOS users can utilize TotalReader or KyBook.

FB2 Technical Info

Full Name: FictionBook 2.0
Developed By: Dmitry Gribov
Initial Release: 2000
MIME Type: application/x-fictionbook+xml

What is an OTT file?

An OTT (OpenDocument Text Template) file is a standardized document template defined by the OASIS Open Document Format for Office Applications (ODF) specification (ISO/IEC 26300). Based on XML syntax and encapsulated within a ZIP-compressed container, the format stores styling definitions, page layouts, and manifest files separate from content, allowing users to generate multiple .ODT files with consistent formatting. It supports lossless compression and interoperability across open-source office suites.

How to open an OTT file

Native support is built into ODF-compliant word processors such as LibreOffice Writer and Apache OpenOffice. Microsoft Word opens OTT files via integrated ODF conversion filters. Because the file functions as a template, opening it typically instantiates a new, untitled document (.odt) rather than editing the template file itself, unless specifically opened for editing via the application's file menu.

OTT Technical Info

Full Name: OpenDocument Text Template
Developed By: OASIS (Organization for the Advancement of Structured Information Standards)
Initial Release: 2005
MIME Type: application/vnd.oasis.opendocument.text-template

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Why RunConvert

The fastest way to convert any file

Purpose-built for speed, privacy, and breadth of format support.

Convert FB2 to OTT in seconds

Every FB2 to OTT conversion runs on our servers, so your device stays fast and the output quality stays intact.

Fast, cloud-powered

No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.

Secure & private

Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.

Free - no account needed

Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.

Developer API

Convert FB2 to OTT via API

Automate FB2 to OTT conversions in three steps: create a job, upload your file, then poll for the result.

# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "tag": "fb2-to-ott",
    "tasks": {
      "upload-file": {
        "operation": "import/upload"
      },
      "convert": {
        "operation": "convert",
        "input": "upload-file",
        "output_format": "ott"
      },
      "export-result": {
        "operation": "export/url",
        "input": "convert"
      }
    }
  }'

# 2. Upload your file (use upload_url from the response)
curl -X PUT "$UPLOAD_URL" --upload-file input.fb2

# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
  -H "Authorization: Bearer YOUR_API_KEY"

Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.