Niconico Downloaders in 2026: 3 Routes to MP4 & Audio

Niconico can be frustrating when a browser downloader fails or returns a file that will not play. To save an authorized video for offline viewing or keep Vocaloid audio with it, choose among an online Niconico video downloader, a desktop MP4/MKV workflow, or a supported browser extension.

If you need to download from Niconico, this guide explains what each route produces and how to avoid mistaking a stream playlist for a playable video. Channel-only releases follow a separate Niconico Channel download process.

How the Niconico Downloader Routes Were Tested

The comparison used a Windows 11 Pro (23H2) PC and a MacBook Air running macOS Sonoma over a stable 500 Mbps fiber connection. The same two Niconico videos were used for the checks:

1. Re:ゼロから始める異世界生活, 4th season #77 (about 24 minutes, encrypted)
2. ビッグ・ラヴ・ミュージック - 初音ミクV6 (about 5 minutes, not encrypted)

Each route was assessed on four main criteria:

• Output Quality: What resolution and file type does the tool offer for the selected video?
• Completion Result: Did the checked download complete and produce a playable file with both picture and sound?
• User Experience: Does the workflow stay clear and usable, and does the page introduce intrusive ads, redirects, or unnecessary installation prompts?
• Audio Handling: Does the saved result include the available audio track, and does the tool identify its format clearly?

A Desktop Niconico Downloader for MP4 and MKV

Real-time recording can take as long as the video itself and may add extra work when audio, subtitles, or metadata need organizing. For a standard local-file workflow, KeepStreams for M3U8 is available for Windows and macOS and saves supported videos as MP4 or MKV.

KeepStreams primarily uses direct-download and remux workflows; the exact processing method depends on the Niconico source, title, and current compatibility. KeepStreams also provides separate site-specific workflows, including its Bilibili URL download guide.

Download and install KeepStreams for M3U8 from the official installer, then follow the steps below for a supported Niconico video.

If the video or your preferred quality requires Niconico Premium, sign in with an account that has viewing access to the title.

If the orange download button does not appear, refresh the watch page and retry the same video before changing other settings.

In the pop-up window, review the available video, audio, and subtitle options, then click Download Now. The source video and your account access determine which settings are available.

Open the Downloads section to view the current progress and download speed, then locate completed MP4 or MKV files in the output folder. Check the completed file for picture, sound, and any subtitle track you intended to keep before relying on it offline.

Online Niconico Video Downloader Options: MP4 and Streams

Online tools are most useful for a permitted one-off public video, but the result may be a playable file, a stream playlist, or no output when the page, viewing session, or parser is unsupported. Treat this route as a convenience option rather than a substitute for checking the saved file.

1. Copy the public Niconico watch-page URL for content you are authorized to save.
2. Paste the URL into the browser tool instead of using a search, list, or temporary media URL.
3. Select the actual file output offered and save it.
4. Open the result and confirm that both picture and sound play correctly.

An M3U8 file is an HLS playlist, not a completed MP4 video. Renaming the extension does not assemble its media segments or merge separate audio and video tracks; a file-producing tool or a workflow designed to download HLS videos is required for that task.

If a download fails, start with the watch-page URL and reopen the viewing session. For missing audio, choose a merged audio-and-video result when offered. If the page layout or parser has changed, update the tool; stop if the video is unavailable to your account.

TubeOffline remains online as a general downloader, but current Niconico-specific compatibility was not confirmed for this review. Avoid treating any online service as verified solely because its homepage is still accessible.

PasteDownload Now Uses a Universal Downloader

As of October 2026, PasteDownload's Niconico-specific page redirects to its universal downloader. The universal downloader explicitly excludes content that requires sign-in and does not confirm current Niconico-specific compatibility, so it should not be presented as a reliable route for Premium, member-only, or other gated Niconico videos.

The universal page does not guarantee a playable MP4 result for Niconico. If a saved public video does not open in the default macOS player, VLC supports a broader range of media containers and codecs.

Browser Extensions for Niconico Downloads

Browser extensions can place a download control directly on the Niconico playback page, but each extension has its own browser and system requirements. The current nico downloader route below is documented for Chrome, while older Firefox extensions should not be assumed to provide the same 2026 compatibility.

When it comes to browser extensions, Video DownloadHelper might be the first one you think of. It is a general-purpose extension rather than a current Niconico-specific recommendation. Awesome NicoNico Downloader remains listed for Firefox, but its listing was last updated on September 30, 2020.

Available Extensions for Niconico in 2026: Nico Downloader

For a more specific option, the Chrome Web Store lists nico downloader version 5.0.0.21, updated September 30, 2026. Its documented scope covers watch pages with sm IDs; nm and so IDs are generally unsupported.

Niconico comments are separate from the saved MP4 or AAC media. The current nico downloader developer notes still list comment downloading as a feature under consideration, so saving the video does not automatically preserve scrolling Danmaku.

Here's how to configure and use nico downloader with a supported Niconico watch page:

After adding the extension from the Chrome Web Store, open a supported Niconico video with an sm watch ID. Click the extension's settings button at the bottom right of the screen, then turn off "Initial Setup Mode". If this configuration is not completed, the download control may not appear or the task may fail.

Refresh the video page. After the page finishes loading, a dedicated "[video ID].MP4 Save" button should appear near the bottom-right area of the player for a supported video.

Click the save button. For supported videos, the extension runs its download and conversion process in the background and combines the available video and audio into MP4. If you only need the audio, the developer also documents separate AAC output.

Conclusion

For a permitted one-off public video, a browser route is the lightest option when it produces a playable file with both picture and sound. The nico downloader extension is a practical fit for supported sm watch IDs, while nm and so IDs and encrypted videos are generally outside its documented scope.

For supported content that you want to save as a standard local file, the official KeepStreams for M3U8 desktop installer and free trial provide a Windows and macOS workflow with MP4 or MKV output and source-dependent video and audio options. KeepStreams primarily uses direct-download and remux workflows; exact processing depends on the source and current compatibility, and the workflow does not require the real-time playback duration of screen recording.