PortBayvsNimbalyst
NimbalystNimbalyst and PortBay both put coding agents on a board and isolate parallel runs in git worktrees, and both are open source and local-first. They diverge on what surrounds the agent. Nimbalyst surrounds it with editors: markdown, mockups, Mermaid, Excalidraw, CSV, data models and Monaco code, all WYSIWYG, so you review and reshape an agent's artefacts by hand. PortBay surrounds it with a running application: managed PHP and Node, seven database engines, trusted HTTPS on a .test domain, captured mail and a one-click tunnel. One helps you edit what the agent wrote. The other gives it something to build against.
Which one is right for you
You want the full stack, open source.
The agent's work has to be provable against a live app — a migration to run, a page to load over HTTPS, an email to catch — and you want the board, the runtimes and the database in the same app you already use for local development. You want a per-project macOS Seatbelt sandbox with a network policy around every run, and an importer that reads your existing Herd, ServBay, MAMP or Valet sites.
It already fits your workflow.
You want the visual layer, free and unrestricted. Nimbalyst's WYSIWYG editors — markdown, mockups, Mermaid, Excalidraw, CSV, data models, Monaco — ship MIT-licensed on macOS, Windows, Linux and iOS at no cost, with an extension SDK on top. PortBay's visual editor is narrower by design and sits behind Pro plus an early-access opt-in, on macOS. If you are on Windows, if you want to review an agent's diagrams and mockups rather than its diffs, or if you want a mobile companion, Nimbalyst is the better fit and the release cadence in its repository is fast.
Where PortBay and Nimbalyst actually differ
The table below has the row-by-row detail. These are the three shapes it cannot draw: the job you already use one of them for, the job only one of them does, and what survives the move.
PortBay and Nimbalyst overlap on the everyday job: a local site on a real domain, over HTTPS, with the services it needs. If that is all you need, either will do it.
Claude Code
Codex
CursorMove a card to To Do and PortBay launches Claude Code, Codex or Cursor against a project that is already running. Nimbalyst has no board to dispatch from.
Point PortBay at the folders you already have. They stay where they are, .test domains are re-issued on the first run, and databases are imported rather than rebuilt.
Feature by feature
Nimbalyst rows come from Nimbalyst’s own site and docs, on the date below. PortBay rows come from the app’s source. We mark partial support honestly — including where the other side wins.
Nimbalyst facts on this page were last checked against github.com/nimbalyst/nimbalyst on . Pricing and limits change — check their site before you decide.
Already using Nimbalyst?
Keep it. These two compose better than they compete: both dispatch the agent CLIs already installed on your machine, so your Claude Code and Codex subscriptions, your CLAUDE.md and your worktree habits carry over unchanged. Nimbalyst is where you shape a spec, a diagram or a mockup by hand before an agent touches code. PortBay is where the card runs once there is code to run — with the runtime, database, HTTPS and mail already up so the agent can check its own work. Point PortBay at the same repository and press play; nothing about your Nimbalyst setup changes.
Install PortBay and add the repository you have been running Nimbalyst sessions against.
Press play — PortBay provisions the runtime, a database and trusted HTTPS for that project.
Create a card, assign Claude Code or Codex, and move it to Todo — the run happens inside the running app, under a Seatbelt profile, in its own worktree.
PortBay vs Nimbalyst, in plain terms
PortBay runs the environment. The card that dispatches Claude Code or Codex has a managed PHP or Node runtime behind it, a per-project database from seven engines, trusted HTTPS on a real .test domain, captured outbound mail and a one-click Cloudflare tunnel — so an agent can migrate a schema, load the page and read the email it just sent. PortBay also confines each run in a macOS Seatbelt profile with a per-project network policy, and imports sites you already have in Herd, ServBay, MAMP or Valet. Nimbalyst provisions none of that; its README and site describe no runtimes, databases, HTTPS or tunnels.
The visual layer, and it is not close. Nimbalyst ships WYSIWYG editors for markdown, mockups, Mermaid, Excalidraw, CSV, data models and code in Monaco, plus canvas and project boards, an extension SDK for adding more, red/green review of each proposed edit inside the rendered document, real-time multiplayer on shared documents, and an iOS companion — all MIT-licensed and free for individuals on macOS, Windows and Linux. PortBay's visual editor is a different tool for a different job: it edits the source file behind an element on your running site, and it is Pro plus an early-access opt-in, macOS only, and absent from the open-source build.
Yes. The repository at github.com/nimbalyst/nimbalyst is MIT-licensed and the site says "Free for individuals. Works with your existing Claude Code or Codex subscription or API key." There is a paid team tier for collaboration features. PortBay is AGPL-3.0, free on the Community plan for up to 6 projects, and $10/month for Pro — or free for life with a merged qualifying pull request or a GitHub sponsorship.
PortBay, by count. Nimbalyst's README lists Codex and Claude Code, with OpenCode and Copilot marked alpha. PortBay dispatches 11 out of the box — Claude Code, OpenAI Codex, Cursor, Gemini, Aider, Copilot CLI, OpenCode, Amp, Qwen Code, Antigravity and Ollama — plus any other CLI via a Custom command template. That matters less than it sounds if you only ever run Claude Code — both auto-detect the CLIs you already have and use the subscription you already pay for.
What the worktree contains. In Nimbalyst a parallel session gets an isolated checkout and the editors around it. In PortBay the same card gets a checkout at .portbay/worktrees/<card-id> plus a running application to point at: a pinned runtime, a database from seven engines, HTTPS on a .test domain and captured mail, with a board-level concurrency cap deciding how many run at once and a macOS Seatbelt profile confining each one. If your work is documents, specs and diagrams, the checkout is enough. If it is a migration or a page you need to load, it isn't.
Yes, and it is the sensible arrangement. They store their state in different places, dispatch the same agent CLIs, and neither takes ownership of your git remote. Use Nimbalyst to draft and visually review the plan; use PortBay for the cards where the agent needs the app actually running underneath it. Nothing about running one prevents the other.
Nimbalyst is one of the tools people compare against Vibe Kanban, and Nimbalyst runs its own comparison hub naming Claude Code, Codex, Cursor, Conductor, Sculptor, Warp and Zed among others. If you arrived here looking for a Vibe Kanban replacement, the honest split is: Nimbalyst if you want the board plus a visual document workspace, free and cross-platform; PortBay if you want the board plus the local environment the agent builds against. We also compare PortBay with Vibe Kanban, Conductor, Kanbots and Emdash directly.
Give your projects and your agents a real local home.
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