Firefox Session Reader: Open sessionstore.jsonlz4
Read a Firefox session backup and get your tabs back as a list you can reopen.
Runs entirely in your browser. Nothing you paste or open is uploaded.
0 windows0 open tabs0 recently closed
Where Firefox Keeps Session Backups
Firefox saves your open windows and tabs in your profile folder, in a compressed format called jsonlz4. To find your profile folder, type about:support in the address bar and click “Open Folder” (or “Show in Finder”) next to Profile Folder.
| File | What it contains |
|---|---|
| sessionstore.jsonlz4 | The session saved when Firefox last closed normally |
| sessionstore-backups/recovery.jsonlz4 | The most recent state while Firefox was running, updated every few seconds |
| sessionstore-backups/recovery.baklz4 | The state before the latest recovery file |
| sessionstore-backups/previous.jsonlz4 | The session from before the last restart |
| sessionstore-backups/upgrade.jsonlz4-… | A copy made when Firefox updated |
Close Firefox before copying these files, or copy them to your desktop first, so Firefox doesn’t overwrite them while you work.
How to Get Your Tabs Back
Copy the backup file
Copy recovery.jsonlz4 or previous.jsonlz4 from sessionstore-backups to your desktop.
Open it here
Drop the copy into the box above. Your windows, tabs and recently closed tabs appear as a list.
Save or reopen the tabs
Export them as bookmarks or a URL list, or copy the links into the Bulk URL Opener.
Frequently Asked Questions
What is sessionstore.jsonlz4?
It’s the file where Firefox stores your open windows and tabs so it can restore them. It’s JSON compressed with Mozilla’s LZ4 format, which is why it can’t be opened in a text editor.
How do I open a jsonlz4 file?
Drop it into this tool. It decompresses the file in your browser and lists every window and tab, with no upload.
Which Firefox file has my lost tabs?
Try sessionstore-backups/recovery.jsonlz4 first, then recovery.baklz4 and previous.jsonlz4. Each is a snapshot from a different moment.
Can I restore the file into Firefox directly?
Yes, with Firefox closed you can replace sessionstore.jsonlz4 with a backup copy. Keep a copy of the current file first, because replacing it overwrites your current session.
Related
- BrowsersSave and Restore Firefox Tabs and Tab GroupsManage Firefox tabs: Restore Previous Session, sessionstore files, tab groups, and how BelayTab adds named sessions, snapshots and exports.
- FeaturesHow to Recover Tabs After a Crash, a Close or an UpdateHow to recover tabs in any browser right now, with shortcuts for each. Then how BelayTab snapshots, version history and trash stop you losing them again.
- ToolsBulk URL OpenerPaste a list of links and open them all at once, or save them as a session.
- HelpUsing the Recovery Screen to Get Lost Tabs BackThe Recovery screen gathers every way back to lost tabs: deleted sessions, automatic snapshots, recently closed windows and export files.
Keep Your Tabs Safe, Too
BelayTab saves and snapshots your tabs automatically, in every browser. Free.