Yes. Happy is MIT-licensed open source with a free hosted relay and free mobile apps — there is no paid tier. dev-mux is paid infrastructure (Solo $25/mo) because it runs an always-on, single-tenant hub for your fleet.

Does Happy work with tmux sessions?

Not the ones you already have. Happy sessions live inside its own CLI wrapper ('happy claude'), so it can't adopt an existing tmux session. dev-mux is tmux-native: it adopts, persists, and relays the sessions already running on your machines.

Can I use Happy and dev-mux together?

Yes. Happy's CLI wrapper is just a process — you can run 'happy claude' inside a dev-mux tmux session on any spoke. You'd get Happy's phone client for that session and dev-mux's fleet map, attention signals, and persistence around it.

Which is more private, Happy or dev-mux?

Both take privacy seriously, differently. Happy end-to-end encrypts session content so its relay can't read it, and the relay is self-hostable. dev-mux removes the third party entirely: traffic rides your own Tailscale (WireGuard) tailnet between your devices, your hub, and your machines, and the hub never stores your code.

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dev-mux vs Happy

Happy is the most popular free way to drive Claude Code from your phone — open source (MIT, ~23k GitHub stars), end-to-end encrypted, genuinely good at what it does. dev-mux charges $25/mo, so this page owes you a straight answer to an obvious question: why pay? The short version: Happy is a synced client; dev-mux is fleet infrastructure. They solve different problems, and below the surface they barely overlap.

TL;DR — If you want to watch and approve a couple of agent sessions from your phone, use Happy; it's free and built for exactly that. If you're operating many agents across many machines and need to know the state of everything — including when nothing is watching — that's what a control plane is for, and that's dev-mux.

What Happy actually is

Happy has four parts: a CLI wrapper (happy claude) that replaces your claude command, a per-machine background daemon, a zero-knowledge relay server (free hosted instance, or self-host via Docker), and mobile/web apps. Session content is end-to-end encrypted before it touches the relay, and the phone gets push notifications for approvals, remote approve/deny, voice, and even remote session spawning. Sessions from several machines appear together in one app.

At a glance

As of July 31, 2026. If something here is stale, tell us.

	dev-mux	Happy
What it is	Self-hosted fleet control plane	Free synced client for agent sessions
Sessions	tmux-native — adopts sessions you already have; they survive everything	Live inside the `happy` CLI wrapper only
Fleet view	Live, freshness-aware map of every machine, repo, and agent	Session list across machines; no machine health, no staleness signal
When a machine dies	Flagged stale within seconds	Its sessions just go quiet
Attention	Hook-level signals (waiting / done / error) + escalation	Push on permission requests and completion
Network path	Your own Tailscale tailnet; no third party	E2E-encrypted relay (hosted by Happy, or self-hosted)
Machine floor	bash 3.2 + tmux + git	Node 20+ wrapper + daemon per machine
Surfaces	Browser cockpit, TUI, iOS, G2 glasses, Telegram	iPhone, Android, web
Teams	Team plan: 5 seats, shared fleet, roles	No team model
Usage / budgets	Per-provider usage dials	—
Behind it	A company you pay, with support and an SLA posture	Volunteer open source; no company, no funding
Price	Solo $25/mo · Team $100/mo	Free (MIT)

Where Happy shines

Price and reach — free, on both app stores, running in minutes with a QR pairing flow.
Real end-to-end encryption — the relay stores blobs it cannot read; the crypto design is genuinely careful.
Phone-first ergonomics — approvals, voice, and answering an agent's questions from a lock screen are polished.

Where dev-mux is a different animal

It adopts what you already run. Happy only sees sessions started through its wrapper. dev-mux is tmux-native: the sessions on your boxes today — however you started them — join the fleet, persist, and relay to every surface.
State exists whether you're looking or not. A synced client shows you what your phone is subscribed to. The hub is always on: it polls every spoke, knows every agent's state, tracks machine health, and marks anything stale within seconds. With Happy, a dead daemon is indistinguishable from a quiet one.
No third party in the path. E2E encryption is a strong answer to "can the relay read my traffic?" dev-mux removes the question: everything moves inside your own WireGuard tailnet, and the hub never stores code.
A fleet is the unit of operation. Roster, roles, worktree sessions, usage dials, Linear wiring, team seats — none of this has an equivalent in a session-sync client.
Someone answers the phone. Happy is admirable volunteer OSS, and its own community has voiced frustration about responsiveness. dev-mux is a product with a company behind it; that's part of what the subscription buys.

Using both

Nothing stops you: happy claude is a process like any other, so it can run inside a dev-mux tmux session on a spoke. You'd keep Happy's phone client for that session and gain the fleet map, attention signals, and persistence around it. If you're evaluating dev-mux while using Happy today, that's a zero-risk way to try it.

Common questions

Is Happy free?

Yes — MIT-licensed, free hosted relay, free apps, no paid tier. dev-mux is paid because it runs always-on, single-tenant infrastructure for your fleet.

Does Happy work with my existing tmux sessions?

No — Happy sessions exist inside its CLI wrapper. dev-mux adopts the tmux sessions you already have.

Which is more private?

Both are serious about it, differently: Happy E2E-encrypts through a relay (self-hostable); dev-mux removes the relay — your own tailnet, hub never stores code.

A client shows you a session. A control plane runs the fleet.

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Written 2026-07-31 against Happy's public repo, docs, and apps. Happy is a trademark of its authors; no affiliation or endorsement implied. Corrections welcome.