Second Life Viewers: Comprehensive Comparison

Snapshot date: 30 September 2026

This document compares Linden Lab’s official Second Life clients with every third-party viewer (TPV) listed in the Third Party Viewer Directory, plus subset/mobile/text clients and Phostwood, which is not yet listed. Listed and not-yet-listed clients are compared side by side; a Directory column records which is which. Viewers with no 2026 public release — stale Directory listings, discontinued projects, and viewers blocked from the grid — are out of scope here. Directory listing is self-certification of policy compliance, not Linden Lab support, endorsement, or a guarantee of current compatibility.

Primary sources

• Third Party Viewer Directory (wiki revision 1218314, last edited 21 May 2025; still the live directory)
• Inara Pey — Current viewer release list (checked 30 September 2026)
• Official Alternate Viewers
• Policy on Third-Party Viewers
• Individual TPV wiki pages, project sites, and 2026 release notes

Versions and platform claims below are as of this snapshot. Nightly/alpha/beta builds change quickly; treat them as current only on the project’s own download page.

Snapshot (September 2026)

Linden Lab

Third-party viewers with 2026 public releases

Directory = listed in the Third Party Viewer Directory. Listing is self-certification of policy compliance, not an endorsement, and it is not a precondition for being compared here.

Projects with no public 2026 release are not in this snapshot.

Master comparison matrix (full graphical clients)

Legend: Y = yes; P = partial or optional; N = no; ? = not documented at this snapshot. Directory = listed in the TPV Directory (— = not a TPV; “Not yet” = unlisted, self-certification planned).

Subset / mobile

Feature-level comparison

Graphics and media

Cool VL is the only LL-derived viewer that documents a supported non-PBR renderer that still shows PBR objects via diffuse fallback. Phostwood is the only current full client whose renderer is Vulkan rather than the LL OpenGL path.

Sound and voice

Grid fact for 2026: WebRTC is the only in-world voice service. Vivox / SLVoice.exe is gone. LL voice morphs / voice fonts are gone with it (they were a Vivox product). Spatial mix is server-side (positions over the WebRTC data channel). Parcel music and media-on-a-prim (MoaP) still go viewer → stream URL, not through the sim.

Shared capabilities (all LL-derived 2026 desktops)

Official, Firestorm, Cool VL, Kokua, Black Dragon, Megapahit, and (with less documentation) Kirstens all implement the stock SL audio model: 3D attached/object sounds (Ogg Vorbis), UI/UI-click sounds, gesture sounds, parcel audio stream, MoaP, and WebRTC spatial / group / conference / P2P. Differences are the mixer, voice module, and Tpv extras.

Playback engine and voice stack

Voice feature grid

Music, media, and local sounds

Subset / mobile

RLV / RLVa

Scripted furniture, collars, and cages that say “needs RLV” work on either family in the common case. Edge-case @ commands can differ; collar makers usually test Firestorm RLVa first.

That is every comparison grid. For what each client actually is — who maintains it, what it does differently, where the source lives — continue to Viewer detail.

Viewer detail

The write-ups behind the grids above — what each client is, who maintains it, what it does differently — plus lineage and source repositories.

Official Linden Lab clients

Second Life Viewer (default desktop)

• Home: secondlife.com/support/downloads and secondlife.com/downloads (the Lab now also links Firestorm on the same page as the popular TPV)
• Repo: github.com/secondlife/viewer (git clone https://github.com/secondlife/viewer.git) — LGPL 2.1. Default, RC, and project viewers are channels/tags of this same repository, not separate trees. Org: github.com/secondlife.
• Current default: 26.3.0.31203661088 — maintenance: inventory favorites from worn objects, Windows 11 Voice Clarity, avatar-complexity performance, laptop dGPU selection, UI performance, WebRTC crash fixes, appearance-system fixes (Kitty Barnett), block-list fixes
• Always first for new protocol, PBR, glTF import, MFA, marketplace integration, and security
• Native Apple Silicon since viewer 2025.07 (7.2.2 Universal Binary). Best non-technical Mac choice if you do not need RLV/AO
• No RLV, no built-in AO, no Firestorm-class radar/asset manager/poser. That is the usual reason people leave it
• Linux: community-dependent for years; experimental Linux returns on 26.4 (Lua Editor RC), not on 26.3 default
• Support: Linden Lab. If a TPV bug is “not in the official viewer,” Lab support will say so

Use it when: you want stability, day-one PBR/voice/security, Apple Silicon battery life, or to confirm a bug is not TPV-specific.

Alternate official viewers (not TPVs)

Linden Lab runs extra channels:

Snowglobe (2009–2011) was Linden Lab’s community-oriented open-source branch of Viewer 1.x and is historical. Viewer 1.23, Viewer 2, and Viewer 3 are likewise obsolete on the live grid.

Second Life Mobile (official)

• Stores: iOS, Android
• Site: secondlife.com/mobile
• Repo: none public (proprietary Linden Lab app). Desktop chat-merge work lives in secondlife/viewer (Chat Modernization channel).
• Public beta, free for all accounts. 3D world view (not text-only)
• Walk/run/fly/sit, touch, outfits, nearby/group/IM, Destination Guide, favorites, teleport offers, bubble chat, object chat, streaming audio, iOS L$ IAP (Android IAP in progress through 2026)
• Not a replacement for building, inventory power tools, RLV, or photography
• Chat Modernization on desktop is specifically about making Mobile and desktop IM feel like one conversation

Full graphical TPVs

Directory-listed and not-yet-listed clients are described together; the Directory column in the grids above records which is which. Listing is self-certification, not a quality bar.

Firestorm — majority daily driver

• Org: Phoenix Firestorm Project Inc. (successor to Phoenix, which succeeded a cleaned Emerald feature set)
• Site: firestormviewer.org
• Wiki: wiki.firestormviewer.org
• Repo: github.com/FirestormViewer/phoenix-firestorm (git clone https://github.com/FirestormViewer/phoenix-firestorm.git). Build variables: FirestormViewer/fs-build-variables. Org: github.com/FirestormViewer.
• Version: 7.2.4.80712 (1 June 2026), aligned with LL 26.1.1 (so it can trail default 26.3/26.4 by a release)
• Platforms: Windows (AVX2 optional), macOS (Intel + Apple Silicon native from 7.2.3), Linux 64-bit
• Grids: SL-only Havok builds and OpenSim builds (OpenSim builds lack Havok; matters for mesh physics upload and pathfinding)

Why it dominates

• Largest feature set: built-in AO, radar, contact sets, area search, keyword alerts, media filter, LSL preprocessor, local bitmaps, local mesh (glTF + auto-reload in 7.2.4), poser, prim align, estate tools, Flickr upload, spam filters, multiple skins including V1-like
• RLVa
• 24/7 volunteer support in multiple languages; in-world support region
• Documentation and YouTube volume unmatched — new-user classes assume Firestorm

Costs

• Heavier RAM/CPU than Cool VL, Alchemy-class, or Genesis
• Release cadence is careful: new LL tech (PBR, WebRTC, Apple Silicon) arrives after Firestorm integrates and tests, not on LL day one
• UI density overwhelms some users (skins and “quick prefs” mitigate this)

7.2.4 highlights: avatar alignment/facing, contact-set and conference/IM tab work, anti-phishing URL display, WebRTC crash/reconnect/PTT/device fixes, Local Mesh glTF, PBR inspect/VRAM estimate fixes.

Cool VL Viewer — oldest maintained TPV, V1, performance

• Author: Henri Beauchamp (Cool SL Viewer from 16 November 2007)
• Site: sldev.free.fr / sldev.pages-perso.free.fr
• Repo: no public git. Per-release source tarballs from the project download/sources page (example: CoolVLViewer-src-132449.tar.bz2 for 1.32.4.49). “Sources repository” is linked from the homepage. Henri’s GitHub vldevel holds LL-viewer contribution forks, not the Cool VL tree. An unofficial historical git dump exists at LiruMouse/CoolVL (not maintained).
• Cadence: stable weekly; experimental branch when needed
• Platforms: Windows x86_64, Linux x86_64 and aarch64; macOS being dropped after the 1.32.4 line (must self-compile after that)

Distinctives (several exclusive)

• Modernized V1 UI that does not jump layout every LL release
• Lua viewer automation (predates LL’s 26.4 Lua editor; different API)
• Dual renderer: Extended Environment (ALM + forward) and PBR, with diffuse fallback for PBR-only assets in non-PBR modes — unique among current TPVs
• Custom texture fetcher / bias to fight VRAM thrash and hitching
• Smart FPS limiter that spends spare CPU on rezzing
• Marine Kelley RLV fork (not RLVa), disabled by default
• Kept features others dropped: classic clouds, terrain-only map, animated Linden trees
• OpenSim: viewer-side baking, varregions, Lightshare
• 2K textures, PBR terrain (base color also in ALM/forward), high-res probes/mirrors, glTF/HDRI previews in PBR mode, MFA, group IM backlog, inventory thumbnails, WebRTC

Kokua — V7 + original RLV, three desktop OSes

• Site: kokua.atlassian.net
• Downloads: project Downloads page (no-RLV and RLV packages); binaries also on SourceForge kokua.team-purple.p
• Repo (canonical): bitbucket.org/kokua/kokua (git clone https://bitbucket.org/kokua/kokua.git). Release integration tree: bitbucket.org/kokua/kokua-release. Build variables: bitbucket.org/kokua/viewer-build-variables. Older GitHub mirror: github.com/kokua/kokua (not the 2026 working copy).
• Lineage: Imprudence → Kokua
• Version: 26.3.0.x (August 2026) — follows LL version numbers more closely than Firestorm’s 7.2.4
• Platforms: Windows, macOS, Linux (including 64-bit)

Kokua’s directory pitch: releases with and without Marine Kelley’s RLV, plus a selection of original features and ports from other TPVs. It is the usual recommendation when someone wants original RLV (not RLVa) in a modern V7 viewer.

Black Dragon — visuals first (Windows)

• Author: NiranV Dean (formerly Niran’s Viewer)
• Site: niranv-sl.blogspot.com
• Repo (canonical): github.com/NiranV/Black-Dragon-Viewer (git clone https://github.com/NiranV/Black-Dragon-Viewer.git). Older GitLab tree: git.alchemyviewer.org/NiranV.Dean/blackdragon. GitHub tags include Release 5.6.3 (July 2026).
• Version: 5.6.0 (1 March 2026)
• Platforms: Windows only

Black Dragon changes defaults, strips “bells and whistles,” and redesigns UI (pie menus, hostile-to-new-users density). The rendering extras are the point:

• Godrays, screen-space reflections, motion blur
• Exodus-descended post-process (tone mapping, color correction, vignette)
• Visual fine-tuning beyond stock PBR
• Local bitmaps 3.0, chat range rings, custom animation speeds, Qarl align, de-render, RLVa, poser-class tools

Photographers treat it as a studio camera: log in, light, pose, shoot, log out. Daily shopping/clubs in BD is a common complaint (UI + GPU cost).

Kirstens Viewer — perpetual experimental (Windows)

• Author: Kirstenlee Cinquetti
• Downloads: SourceForge kirstensviewers
• Repo: live development is SVN on SourceForge: svn checkout https://svn.code.sf.net/p/kirstensviewers/code/ kirstensviewers. Browse: sourceforge.net/p/kirstensviewers/code. A Git snapshot (last noted 16 Apr 2024, not the live S24 DX tree) is at sourceforge.net/p/kirstensviewers/git (git clone https://git.code.sf.net/p/kirstensviewers/git kirstensviewers-git).
• Blog/notes: kirstenleecinquetti.blogspot.com
• Status: S24 DX pre-alpha (September 2026)
• Platforms: Windows

Directory text: hybrid of official sources and custom code for experienced users; anaglyph 3D; aggressive/hardware-specific builds; stability can vary wildly; supplementary to an official client.

2026 work includes a DirectX-oriented path, OpenCL VFX, vcpkg/PowerShell one-click builds. Community reports of high FPS on high-end NVIDIA laptops exist; treat as beta/alpha.

Megapahit — vanilla LL on Mac ARM and Linux

• Site: megapahit.net / megapahit.org
• Repo: github.com/megapahit/viewer (git clone https://github.com/megapahit/viewer.git). Project also documents git clone git://megapahit.org/viewer.git. Packaging: megapahit/ebuild, megapahit/flatpak.
• Author: Erik Kundiman
• Version: 26.4.0.564544 (10 September 2026) — ahead of Firestorm, matching LL’s 26.4 line
• Platforms: macOS (Apple Silicon) and Linux. No Windows
• Goal: “shelter for metaverse refugees” on less-supported OSes; few bundled libraries; small downloads (“megabytes”)

Surface differentiation is intentionally low: it is a close-to-official fork so Mac ARM and Linux users can run current LL code without waiting for Firestorm or compiling Cool VL.

Phostwood — Vulkan / OpenXR, not an LL fork

Not a Linden Lab fork. Not yet Directory-listed. Source unpublished. Site: phostwood.com.

Phostwood is the only current full 3D client in this document that does not descend from the official viewer source. It reimplements the Second Life protocol in C++20 (UDP packets generated from message_template.msg; LLSD, login, circuits, caps written for this engine). The UI is its own: no LGPL XUI or code from any LL-derived viewer is used.

Why it is in this comparison

Every other full graphical TPV here is a fork of Linden Lab’s LGPL viewer (OpenGL, CEF-in-process, same scene graph). Phostwood is the 2026 attempt to do what CtrlAltStudio did for Oculus in the 2010s — first-class HMD support — without inheriting that renderer. The last listed VR TPV (CtrlAltStudio) was withdrawn when LL promised VR and never shipped a resident-usable OpenXR client.

Not yet: Directory-listed.

Directory listings with no 2026 public release (Alchemy, Aperture, Catznip, Genesis, Singularity, Restrained Love, Lovense) are not covered here.

Subset, mobile, and text clients

These omit full graphical parity. They still had a 2026 public release. Stale subset clients (MetaChat, Lumiya, …) are not covered here.

Radegast — non-graphical / accessibility

• Maintainer: Cinder (cinderblocks); avoid unaffiliated SourceForge malware forks (2025 community warning from the maintainer)
• Repo: github.com/cinderblocks/radegast (git clone https://github.com/cinderblocks/radegast.git) — v2.54 (14 July 2026 tag Legacy/2.54). Protocol library: github.com/cinderblocks/libremetaverse. Historical upstream org: github.com/radegastdev/radegast. Site: radegast.life
• Platforms: Windows, macOS, Linux
• Chat, IM, groups, inventory, friends; TTS/STT and accessibility APIs on Windows; later versions add a minimal world view
• Not for: building, shopping visually, PBR

SpeedLight — web viewer

• Site: speedlight.io / docs.speedlight.io
• Repo: none public (closed source). TPV Directory: “No Publicly Available Source.”
• Version: v2026.1 (1 January 2026)
• Platforms: any modern browser; Android and iOS apps
• Teleport, map, search, local/IM/group chat, inventory, L$ send
• Unique: switch devices without logout, multi-avatar, keep avatars online with browser closed, IM history while offline, L$ history

Mobile Grid Client — Android text client

• Site: mobilegridclient.com — Google Play: com.schlager.mgc
• Repo: none public (closed source)
• Version: 1.34.1319 (25 September 2026)
• Platforms: Android only
• Local chat, IM, group chat, people search, mini map, teleport, inventory; SL and OpenSim
• Paid after a trial period. Text client: no 3D view and no voice

Official 3D mobile is covered under Official Linden Lab clients, below.

Lineage (simplified)

Viewer 1.x (LL)
 ├─ Snowglobe (LL community)
 ├─ Nicholaz, Hippo, Meerkat, Onrez, realXtend     [dead]
 ├─ Cool SL Viewer (2007) ──────────────────────── Cool VL Viewer (alive)
 ├─ Imprudence ─────────────────────────────────── Kokua (alive)
 ├─ Ascent ─────────────────────────────────────── Singularity (barely)
 ├─ Emerald [BLOCKED 2010]
 │    ├─ Emergence [dead]
 │    └─ Phoenix [retired] ─────────────────────── Firestorm (alive)
 Viewer 2 / 3 / 7 (LL official — alive)
 ├─ Firestorm (also merges Phoenix-era UX)
 ├─ Catznip (RLVa) [stale]
 ├─ Alchemy [repo alive, release stale]
 ├─ Kokua (V3+ rebase)
 ├─ Black Dragon ← Niran’s
 ├─ Aperture [young]
 ├─ Megapahit (thin LL fork)
 ├─ Kirstens (hybrid experimental)
 ├─ Exodus [stale]
 ├─ Lovense [niche]
 └─ CtrlAltStudio [VR, withdrawn]

 Clean-room protocol reimplementation (not an LL fork)
 └─ Phostwood (Vulkan + OpenXR, unpublished, 0.1.0)

Repositories

Clone URLs below are the canonical public trees as of 19 September 2026. Closed-source clients have no clone URL; that is policy-legal if they never used LL’s LGPL/GPL viewer source, but they still must obey the TPV Policy.

Directory applications (not viewer code): github.com/secondlife/third-party-viewers.

Linden Lab

Default 26.3, RC 26.4, and Chat Modernization are tags/channels of secondlife/viewer, not extra repositories. Linden Lab’s public changeset index: releasenotes.secondlife.com/repositories.html.

Full graphical TPVs

Subset, mobile, text, libraries

No public repo: SL Mobile and SpeedLight are closed source. Phostwood's source is unpublished. Stale and historical trees are out of scope here.

Caveats for this snapshot

• The wiki directory table last changed May 2025; activity after that is tracked from project sites and Inara Pey’s roundup, not from a new TPVD edit.
• Firestorm 7.2.4 tracks LL 26.1.1, while default Official is 26.3 and RC is 26.4. Feature lag of one LL cycle is normal for Firestorm and is not “abandonment.”
• Inclusion requires a public 2026 release. Alchemy’s GitHub had 2026 commits without a 2026 binary; it is not covered here.
• Cool VL macOS support is explicitly ending; do not plan new Mac workflows on it.
• “Best FPS” is hardware- and settings-dependent. Cool VL often wins on low/mid PCs; Black Dragon and Ultra Firestorm lose on purpose for quality.
• Phostwood facts in this file come from its unpublished source tree, re-read 30 September 2026 (version 0.1.0). Its source is unpublished; it is not yet Directory-listed; it is not an LL fork.
• This is not legal advice, not Linden Lab documentation, and not a substitute for each project’s privacy policy.

Compiled 19 September 2026 for the tpv workspace.