twineconvert

free · in-browser · no upload

CSL-JSON to NBIB
Converter

Drop your CSL-JSON file. We'll convert it to NBIB right here in your browser, your file never leaves your device.

or drop your file

Select your file here to get started

or drop your file here.

Accepts .json

nothing uploaded no file size cap no signup

How it works

Three steps. No upload, no signup.

  1. 1

    Drop your file

    Click the dropzone above or drag a CSL-JSON from your desktop. Files of any size, there's no upload, so there's no upload limit.

  2. 2

    Convert in your browser

    The conversion runs entirely in this tab using JavaScript and WebAssembly. Your file never touches our servers, we don't have any.

  3. 3

    Download

    Get your NBIB the moment the conversion finishes. Convert another, or close the tab.

Files stay on your device

Your file is never uploaded. The entire conversion runs in your browser using WebAssembly. We can't see what you convert because we have no server to see it.

No file size limit

Server converters cap free users at 1-2 GB and gate larger files behind a paid plan. Since nothing uploads, our limit is whatever your browser can handle.

Free, no signup, no ads on conversions

No account required. No watermark on the output. No queue. Drop a file, get a converted file.

Why convert CSL-JSON → NBIB

What this conversion is actually for

CSL-JSON is the Citation Style Language JSON that Zotero, pandoc, and citeproc speak; NBIB is PubMed's MEDLINE/NBIB export. This converts one to the other through a shared bibliographic model, so every field that round-trips (title, authors, year, journal, volume, pages, DOI) carries across without re-keying. Runs entirely in your browser, no upload.

A real example

You have a Zotero or pandoc CSL-JSON file and your next tool wants NBIB. Drop the file here and get a clean NBIB file back in one step.

Troubleshooting

Some references are missing fields after conversion.

Fields only carry across if the source CSL-JSON actually contained them. Open the source and confirm the field is populated; NBIB cannot add data that was not there.

Formats involved

About CSL-JSON and NBIB

CSL-JSON, Citation Style Language JSON

CSL-JSON is the modern interop format for citation metadata. Zotero exports it natively (right-click a collection → Export → CSL JSON). Pandoc consumes it as `--bibliography file.json` for reference rendering. Every major reference manager (Zotero, Mendeley, Citavi, Papers, Bookends) reads or writes it. Defined by the Citation Style Language project; covers ~100 fields across journals, books, chapters, theses, software, datasets, and more. The de-facto replacement for BibTeX in modern academic toolchains.

How to open

Any JSON viewer or text editor. Zotero imports via File → Import → CSL JSON. Pandoc references it as bibliography input. JabRef, Citavi, and Bookends all accept CSL-JSON drop-ins.

Full CSL-JSON format guide →
NBIB, PubMed citation format

NBIB is the National Library of Medicine's citation format for PubMed exports. Structurally identical to RIS with a different tag dictionary (PMID, FAU, JT, AID instead of ID, AU, JO, DO). Reference managers treat .nbib files as RIS-flavored with PubMed-specific extensions. The format ships with PubMed downloads and the major systematic-review tools (Covidence, Rayyan).

How to open

Zotero, Mendeley, EndNote, Papers, all read NBIB natively. Plain text in any editor.

Full NBIB format guide →

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FAQ

Common questions

Is this CSL-JSON → NBIB converter really free?

Yes. No signup, no watermark, no daily file count limit. Every conversion runs in your browser, your file never touches our servers because there are no servers.

Where does my file go when I convert it?

Nowhere. The conversion runs entirely in your browser using JavaScript and WebAssembly. Your file is never uploaded to our servers. We don't have any servers handling files, there's nothing for us to log, store, or accidentally leak.

What's the maximum file size?

Whatever your browser can hold in memory. Practically, this means a few hundred MB on most computers, significantly larger than the 1-2 GB caps that server-upload converters charge for. Very large files (multi-GB) may require closing other browser tabs first.

Why convert CSL-JSON to NBIB?

Cross-tool bibliography exchange between reference managers. PubMed citation export; systematic review imports. The most common reason to convert is compatibility, NBIB works in places where CSL-JSON doesn't, or vice versa.

How do I open a CSL-JSON file in the first place?

Any JSON viewer or text editor. Zotero imports via File → Import → CSL JSON. Pandoc references it as bibliography input. JabRef, Citavi, and Bookends all accept CSL-JSON drop-ins.

Does this work offline?

Once the page is loaded, the conversion itself runs entirely offline. The first time you use a tool, your browser downloads the conversion library (a one-time cache). If you reload while offline, the page won't load, but you can install the site as a Progressive Web App for full offline use.

Can I convert multiple files at once?

Single file at a time for now. Batch conversion is on the roadmap, for now, drop one file, download the result, then convert the next.