Competitors: running coding agents remotely or in the background

Researched on 15 October 2026.

Research note for simstim. It compares hosted and open tools that run coding agents away from the laptop, or keep them running in the background.

About this note

• Scope. 28 rows: 11 hosted products, 3 sandbox providers, 13 open or local tools, and simstim itself. Each row has 14 facts, split over three tables.
• Sources. Every cell links a primary source: official docs, pricing pages, repositories, changelogs or official posts. All of them were read on 15 October 2026. Prices are list prices in US dollars on that day, without tax.
• Method. Five research passes ran in parallel, one for each group of rows. I then re-read the most surprising claims myself: Cursor’s new plans, OpenAI’s purchase of Ona, Daytona’s move to closed source, Conductor’s Pro plan, the end of Vibe Kanban’s company, Claude Code’s cloud sessions and Codex’s prices. GitHub figures come from gh repo view on the same day.
• Rules. No sign-ups, accounts, API keys, downloads or paid resources. Public pages only. Closed products are described in my own words.
• Reuse. This note does not repeat what other notes already cover. Amp’s orbs are in Amp UX and Orbs. Herdr’s design is in Herdr. mosh, Eternal Terminal and Tailscale SSH as transports are in Connectivity and providers. zmx is in Host runtime.
• UNVERIFIED marks a claim I could not confirm from a primary source. A “?” in a table cell means the same.

Legend

What each column asks:

Summary

1. No product meets simstim’s whole brief. simstim is the only row with ✅ in all four of: any agent, real TUI pass-through, persistence, and self-hosting. Four rows miss only one:

   • zmx and Eternal Terminal pass the bytes through, but they lose sessions on reboot, and they manage no agents.
   • Herdr persists and manages agents, but it re-draws the screen.
   • Coder gives a real SSH terminal on your own servers, but it stops idle workspaces. It needs tmux to survive a disconnect, and tmux re-draws the screen.

   Codespaces and Daytona are like Coder, but they also run on the vendor’s machines. The hosted agents run one vendor’s agent in a web or app UI: Amp, Claude Code on the web, Codex cloud, Cursor, Jules, Devin, Factory and Warp.

2. The market churned hard in 2025–2026. In this matrix alone:

   • Terragon shut down (9 February 2026).
   • Crystal was deprecated in favour of Nimbalyst (February 2026).
   • Vibe Kanban’s company shut down (10 April 2026).
   • Daytona went closed source (11 June 2026).
   • OpenAI bought Ona, formerly Gitpod (deal closed 10 August 2026). Ona closed new sign-ups, and its built-in agent is now Codex only.
   • SpaceX bought Cursor (14 August 2026). Cursor’s cloud agents now need its $30 Premium plan.
   • Coder removed its Tasks feature and archived AgentAPI.
   • Devin retired its Core and Team plans.

   The full list is in Changes in 2025–2026.

3. Vendors now run their own agent on your machine, but they keep the control plane. Examples: Amp runners, Claude Desktop SSH sessions, Codex’s “Connect to an SSH host”, Cursor’s My Machines, Devin Outposts, Factory’s Remote Control and Warp’s Remote Control. Each is tied to one vendor’s agent, account and UI. See Near misses.

4. simstim already gives away what others sell:

   • an agent that keeps working with the laptop closed (Conductor Pro $50 a month, Cursor Premium $30, Claude and Codex from $20);
   • runs on your own machines (Enterprise plans at most vendors);
   • no session time limits (E2B: 1 hour free, 24 hours on the $150 Pro plan; Modal: 24 hours on every plan);
   • no limit on parallel agents (Jules: 3 free, 15 on the $19.99 plan);
   • a shell and port forwards into the agent’s machine (Devin and Factory, from $20).

5. Cheap wins remain (section Paid features):

   • a host-side notify hook that reaches a phone or Slack (S);
   • stopping cloud VMs after an idle rule (S–M);
   • read-only watchers (M);
   • pull to bring a session’s branch back to the laptop (S);
   • recipes for scheduled runs (S).

6. simstim is behind on reach and isolation. Nothing is released yet, and you must bring a Linux host. There is no phone or web client, and no sharing with other people. There are no per-task sandboxes, no environment snapshots and no managed secrets.

7. simstim is ahead on fidelity, cost and control. It passes bytes through with replay and keeps native scrollback. It has no time, concurrency or compute caps. It works with any agent login and any SSH path. It needs no account, relay or open port, and carries no vendor risk.

8. Updates to the design page. Daytona is now closed source, not just archived. zellij forwards OSC 9 and 777 since 0.45, though it still re-draws the screen. One fact is confirmed: tmux 3.8 still has no kitty keyboard protocol, which is planned for 3.9.

Changes in 2025–2026

Table 1: business

Table 2: session

Table 3: collaboration and lifecycle

Open-source repositories

From gh repo view <repo> --json stargazerCount,licenseInfo,latestRelease,pushedAt on 15 October 2026.

Conductor has no public source. Its release repository, meltylabs/conductor-releases, has 9 stars and no licence.

Near misses: vendor agents on your own machine

These are not rows in the matrix, but they come closest to simstim’s idea of “your agent on your host”. Each one keeps one vendor’s agent, account and UI.

Paid features simstim can give for free

Effort is for what simstim still lacks: S is days, M is a week or two, and L is a month or more. “Done” means it is built today.

Where simstim is behind

1. It is not released. Today you build it from source with Go and just; there is no Homebrew tap and no notarised build (README). Herdr installs with one curl line or brew (docs). Hosted products need only a browser.
2. You bring the host. simstim needs a Linux host that you can already reach with ssh (architecture). Hosted products need only a GitHub login. The first run also needs you to install the agents and log in to them on the host.
3. No phone or web client. This is a non-goal (plan), but Claude, Codex, Cursor, Devin, Amp, Conductor and Nimbalyst all have phone apps or a web UI. simstim’s alerts reach only the desktop, and only while a client runs.
4. No sharing with other people. tmux has read-only attach (man page). zellij has read-only web tokens (0.44). Warp has view and edit roles (docs). Amp has multiplayer orbs (note). simstim serves one user on several devices.
5. Weaker isolation. All sessions on a host share one OS user, one filesystem and one network. An agent with broad permissions can read another session’s files and the host’s logins. Hosted tools give each task its own VM: Claude, Codex, Cursor, Jules, Devin. E2B and Amp give each task a microVM. Claude and Codex also control network egress (environments, environments). simstim gives a memory cap and a worktree, not a sandbox.
6. No environment snapshots, prebuilds or memory hibernation. Amp, Cursor, Devin, Factory, E2B and Daytona start a task from a saved image, and some pause with memory intact. After a reboot, simstim brings back the conversation, not the running turn. That matches Claude’s cloud sessions after a reclaim (docs), but not an E2B or Amp pause.
7. No review flow. There is no diff view, no pull-request button, no CI auto-fix, and no Slack, Linear or GitHub triggers. This is by design, since simstim is not an agent wrapper, but teams do buy these features.
8. No automatic idle stop for cloud VMs. Amp’s orbs pause after 5 to 20 minutes and cost nothing while paused (note).
9. Community. Herdr gathered 44,000 stars in seven months. tmux has 50,000 and zellij 36,000. simstim is private and has no users yet.

Where simstim is ahead

1. The whole brief, in one tool. simstim is the only row with ✅ in all four of: any agent, real TUI pass-through, persistence, and self-hosting. zmx, Eternal Terminal, Herdr and Coder each miss one (Summary item 1).
2. Fidelity. The agent’s bytes are passed through, and missed output is replayed by byte offset, so native scrollback stays continuous (architecture). The other tools fall short:
   • tmux 3.8 has no kitty keyboard protocol and drops the agent’s OSC 52 by default (options).
   • zellij supports only the first kitty level (0.41).
   • mosh supports none (source).
   • Herdr re-draws the screen and drops OSC 9/777 (issue).
   • zmx wipes the scrollback on detach (note).
3. No caps and no compute markup. There are no time limits, no concurrency limits and no per-minute fees; you pay only for your host. For scale:
   • An always-on Amp a1.medium orb (4 vCPU, 8 GB) at $0.33 an hour would cost about $241 a month (sizes). Orbs pause when idle, so real bills are lower.
   • A 4-core codespace costs $0.36 an hour (billing).
   • The first plan cites a 4 vCPU, 8 GB VPS at €8.49 a month.
4. Any agent login. simstim runs the agent’s own CLI on your host, with whatever subscription or key you give it. Claude’s cloud sessions refuse Bedrock, Vertex and API-key logins (docs). Warp’s cloud needs an Anthropic API key stored as a Warp secret (quick start).
5. Any network path. ProxyJump, GCP IAP, AWS SSM and Tailscale all work through ~/.ssh/config (connectivity), including private networks behind a jump host. Hosted runtimes reach a private network only through special features, such as Codex’s Tailscale option (environments).
6. Nothing listens, and nothing phones home. Other tools need an open port, a relay or telemetry:
   • Eternal Terminal needs TCP 2022 open and sends telemetry by default (repo).
   • mosh needs UDP ports (site).
   • Factory’s Remote Control goes through a relay (docs).
   • Cursor’s and Devin’s own-machine modes keep the agent loop in their cloud (Cursor, Devin).
7. Your code and credentials stay on your hosts. Every hosted product holds your repository, and most hold your secrets.
8. No vendor risk. Several products in this matrix were shut down, sold, closed or re-priced in 2025–2026 (see Changes in 2025–2026). A self-hosted Apache-2.0 tool over plain SSH cannot be withdrawn the same way.
9. Remote image paste. Ctrl+V uploads a screenshot and pastes its path (README). Herdr does the same (note). The terminal tools (tmux, zellij, zmx, mosh, Eternal Terminal) have no equivalent.

Unverified

• Amp’s $200 top tier: it appears only in the pricing page’s script, not in its text.
• Whether Codex’s Free and Go plans include cloud tasks.
• Factory: whether Droid Computers come with Pro or Plus (the docs and the pricing page disagree), and when factory.ai moved to factory.com.
• Warp: whether Claude Code and Codex in the cloud need a paid plan (the docs and the pricing page disagree), whether cloud runs have port forwarding, and whether there is phone push.
• Factory phone push.
• Ona’s current licence, and the exact date its own agent was dropped.
• Coder: whether any “agent needs input” notification remains after Tasks was removed.
• Jules: session sharing; Jules has had no changelog entry since March 2026.
• Terragon: its setup steps and whether it had port previews.
• Vibe Kanban: whether phone access through its relay still works.
• Eternal Terminal: kitty keys and OSC 9/777 pass-through in practice.
• E2B: when infra became runtime.
• Tailscale: a pricing table cell that limits Basic SSH to 5 hosts on Standard but not on Personal.

Sources

Each table cell links its own primary source. The link targets are defined at the end of this file. All were read on 15 October 2026.