Clann Tree Viewer
Drop a Newick / NHX file to view

Clann Tree Viewer

A free, browser-based phylogenetic tree viewer for Newick, NEXUS, and NHX files. Open a tree, drag one in, or paste it — then explore, reroot, collapse, colour, rename, and export as SVG, PNG or PDF in cladogram, phylogram, or radial layouts.
Everything runs locally; nothing is uploaded to a server.
.nwk · .newick · .tree · .ph · .phy · .nhx · .nex · .nexus · .txt
↓ About & FAQ

About Clann Tree Viewer

Clann Tree Viewer is a free, open-source phylogenetic tree viewer that runs entirely in your web browser. Open a Newick, NEXUS, or NHX file — or paste tree text — and explore it interactively: reroot (by hand or at the midpoint), ladderize, collapse and expand clades, colour branches, rename tips, and switch between cladogram, phylogram, and radial (circular) layouts. Export publication-ready figures as SVG, PNG, or PDF, or copy the current rooting as Newick.

Because all parsing and rendering happen locally in your browser, your trees are never uploaded to a server. The viewer also visualises gene-tree / species-tree reconciliations from the NHX files produced by Clann, showing duplications, speciations, and losses with per-node species mapping, and can export the annotated NHX.

Frequently asked questions

How do I view a Newick tree online?

Open Clann Tree Viewer, then click “Open file…” or drag a .nwk, .newick, or .tree file onto the window. You can also paste Newick text straight in. The tree renders instantly and stays on your machine.

Can I open NEXUS and NHX trees too?

Yes. It reads NEXUS (.nex / .nexus) files — resolving the TREES block and translate table — and NHX reconciliation files that carry duplication, loss, and species annotations. PHYLIP-style Newick (.ph / .phy) works as well.

Is my data uploaded to a server?

No. Everything runs client-side in your browser, so your trees never leave your computer. You can even save the page and use it offline, or host it yourself.

Can it show gene duplications and losses?

Yes. For NHX reconciliations it marks duplications, speciations, and losses at each node, shows the species mapping in tooltips, and can export the annotated NHX for the current rooting.

What tree layouts are available?

Cladogram (tips aligned to show topology only), phylogram (scaled to branch lengths with a scale bar), and radial/circular — with adjustable row spacing, font size, and branch-line thickness.

How do I export a tree figure?

Download the tree as SVG, PNG, or PDF, or copy the current rooting as Newick or NHX. SVG and PDF are vector, so they stay crisp in papers and posters.

Is it free?

Yes — Clann Tree Viewer is free and open source, developed by CreeveyLab. Use it online or clone the repository and host it yourself.

Developed by CreeveyLab · source on GitHub · companion to the Clann supertree program.