What is the NZB file format?
Files with the .nzb filename extension store indexing data for Usenet (NNTP) newsgroup searches. .nzb files save data in XML-based text format and are broadly comparable to torrent files - both contain information about the location of binary resources on a network rather than the content itself.
.nzb files are generated by Usenet indexing services and allow downloading files organized into categories such as applications, movies, music, or books. Each .nzb file contains:
- Message ID - a unique article identifier (a single file may span multiple messages),
- Poster - information about the author of a given message,
- Date - message creation date,
- Subject - the subject of a given message,
- Groups - list of newsgroups to which a given message is posted,
- Segments - information about the message segments into which an article is divided, including byte counts.
.nzb is a plain text file and can be opened with any text editor; in practice it is loaded into a Usenet download client rather than viewed in a browser. Integrity and repair of downloaded content is handled separately by .PAR2 and .SFV files often posted alongside the main archive.
.nzb files were created by the Newzbin.com indexing service in 2003 as pointer files that allowed users to download binaries - typically packaged as .RAR archives - using a dedicated Usenet client. Newzbin was shut down in 2012, but the .nzb format survived and remains the de-facto standard for Usenet downloads, supported by clients such as SABnzbd, NZBGet, and others. Usenet itself dates from the early 1980s and, though niche today, retains a dedicated user base.
Security & safety
RISK: MEDIUMThe .nzb file itself is harmless text. The risk is in what it downloads: NZB indexers point to user-posted Usenet content that can include malware, fake/mislabeled files, or copyrighted material. Let your downloader run PAR2 verification, scan extracted files with antivirus, and be wary of password-protected posts. Some 'free NZB' sites push adware downloaders - get SABnzbd/NZBGet from their official sites. Downloading copyrighted content via Usenet carries the same legal risk as any other source.
Format details
in a nutshellPrograms that open NZB files
Windows4 apps
NewsLeecher
Paid Open the .nzb in NewsLeecher (File → Open) to queue and download; commercial Usenet client, still maintained. 
NZBGet
Open-source Configure a news server, then drop the .nzb in or upload via the web UI; NZBGet fetches and post-processes it.
SABnzbd
Open-source Add your Usenet server in setup, then drag the .nzb into SABnzbd (or use its watch folder) - it downloads, PAR2-repairs and unpacks.
Notepad / any text editor
Open-source Open the .nzb to read its XML (file list, groups) - for inspection only, it won't download anything. 
macOS2 apps
Linux2 apps
NZBGet
Open-source Lightweight C++ Usenet downloader (revived community fork at nzbget.com) - add the .nzb in the web UI.
SABnzbd
Open-source Install via package/Docker, configure your news server, then add the .nzb (watch folder or web UI).
Provider web downloaders (e.g. Newshosting/Easynews clients)
Paid Some Usenet providers bundle a downloader app that opens .nzb files directly with a built-in news server. Technical details
deep spec| MIME Type | application/x-nzb |
| File Encoding | UTF-8 XML text |
| XML Root Element | <nzb> with XML namespace http://www.newzbin.com/DTD/2003/nzb |
| XML Structure | <nzb> root contains <file> entries; each <file> holds <groups> (newsgroup names) and <segments> (Message-IDs with byte sizes) |
| File Signature | No binary magic bytes; plain XML typically beginning with <?xml followed by a <nzb> root element |
| Compression | Uncompressed plain XML - the .nzb itself carries no compression; referenced content is typically yEnc-encoded and RAR-packed |
| Typical File Size | A few KB to several hundred KB (lists article references only, not binary data) |
| Referenced Content Encoding | Binary Usenet articles are yEnc-encoded; multi-part posts are split into numbered segments |
| Integrity and Repair | Not embedded in .nzb; handled externally by PAR2 parity files and SFV checksums downloaded alongside |
| Platform Support | Cross-platform: Windows, macOS, Linux (any OS with a Usenet client) |
| Segment Elements | Each <segment> element specifies the Message-ID and byte count of one article part on the news server |
| Newsgroup Targeting | <groups> element lists one or more newsgroup names per file entry, commonly in the alt.binaries.* hierarchy |
| Originating Service | Created by Newzbin.com (UK) in 2003; format adopted across the Usenet community after Newzbin's 2012 closure |
| Alternative MIME Type | text/xml - accepted by many Usenet clients when application/x-nzb is not declared in the HTTP response |
| Released | 2003 (created by the Newzbin Usenet indexing service) |
| Latest version | NZB 1.1 DTD (newzbin.com/DTD/2003/nzb) |
| Open standard | Yes · royalty-free |
| Specification | web.archive.org |
NZB conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about NZB files.
