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NCX at a glance
NCX
Convert to NCX when an ebook workflow needs a legacy-compatible navigation map for EPUB 2 readers or for EPUB 3 packages that must still support older reading systems.
It is useful in production pipelines where table-of-contents structure needs to survive across mixed generations of ebook software.
JSON at a glance
JSON
Convert to JSON when data needs to move between systems, APIs, scripts, and applications in a structured but broadly compatible format.
It is ideal for payloads, configuration, manifests, exports, and machine-readable documents that need to be easy to parse programmatically.
Use it when interoperability and structured automation matter more than comments or document-style readability.
Format comparison
| Feature | NCX | JSON |
|---|---|---|
| File type | Other | Other |
| Extensions |
|
|
| MIME type |
|
|
| Compression / quality | depends | depends |
| File size characteristics | depends | depends |
| Compatibility | moderate | moderate |
| Editability | moderate | moderate |
| Created year | 2005 | 2001 |
| Inventor | DAISY Consortium | Douglas Crockford |
| Status | active | active |
| Transparency | Not supported | Not supported |
| Animation | Not supported | Not supported |
| Primary use cases |
|
|
| Common software |
|
|
| Archival suitability | moderate | moderate |
| Metadata handling | moderate | moderate |
| Delivery profile | moderate | moderate |
| Workflow fit | exchange | exchange |
| Vector scaling | Not supported | Not supported |
| Reflowable text | Supported | Not supported |
| Structured data | Supported | Supported |
| Streaming ready | Not supported | Not supported |
When to use each format
When to use NCX
- system exchange
- automation
- specialized interoperability
- Provides a dedicated hierarchical navigation tree for legacy ebook systems.
When to use JSON
- system exchange
- automation
- specialized interoperability
- Easy to parse across nearly every modern programming environment.
FAQs
Why convert NCX to JSON?
Convert to JSON when data needs to move between systems, APIs, scripts, and applications in a structured but broadly compatible format.
It is ideal for payloads, configuration, manifests, exports, and machine-readable documents that need to be easy to parse programmatically.
Use it when interoperability and structured automation matter more than comments or document-style readability.
What changes when converting NCX to JSON?
This conversion changes how the format behaves in downstream tools and delivery environments.
Moving to JSON removes reflowable text.
What should I review after converting NCX to JSON?
Check the exported file for It has no native comment syntax in the core format.; Human maintainers often prefer other formats for long configuration files..