Comparison · July 2026
Uno vs Bullet Train
Bullet Train is free and MIT-licensed — if price is the only axis, it wins and you can stop reading. This page, written by Uno's author, is about what you trade for free. Facts are verifiable on bullettrain.co and GitHub.
| Uno | Bullet Train | |
|---|---|---|
| Price & license | One-time purchase ($199/$249), commercial licence, unlimited projects | Free, MIT-licensed, fully open source |
| View layer | Phlex 2 — views are pure Ruby objects | ERB with "Nice Partials" theme engine, Turbo + Stimulus |
| Runtime dependencies | PostgreSQL only — no Redis, no Node runtime in production | Redis required (Action Cable + Sidekiq); esbuild + PostCSS build chain |
| Background jobs | Solid Queue on Postgres, Mission Control dashboard | Sidekiq on Redis |
| Auth | Magic links, one-time codes, Google & Apple OAuth, Devise, JWT rotation for the API | Devise + two-factor, 100+ OAuth providers claimed |
| Teams / roles | Single-account model out of the box | Deepest team model in the Rails template space: teams, invitations, roles gem, onboarding |
| Admin | Purpose-built panel: impersonation, roles with audit history, flags, moderation, jobs, events | Avo-based admin |
| Code generation | None — conventions and docs instead | Super Scaffolding, Action Models, OpenAPI 3.1 schema generation |
| AI-agent readiness | Built for it: AGENTS.md, 40+ per-feature docs, agent-legible pure-Ruby views, N+1 guard failing the build | No AI-agent positioning or tooling as of July 2026 |
| Event sourcing / audit | Rails Event Store — every state change recorded and replayable | PaperTrail-based audit logs |
| Deploy | Kamal 2 + Docker + Thruster to any VPS, wired end to end | Deploy-agnostic |
| Support model | Author support (priority on the Complete tier), updates driven by production apps | Community: Discord + GitHub issues; no commercial support tier |
Facts checked July 2026 against bullettrain.co and the bullet_train GitHub repository. Corrections: rafal@piekara.me.
Choose Bullet Train if…
- Budget is zero — MIT-licensed and genuinely free is unbeatable on price.
- Teams, invitations, and role-based permissions are your core product shape — nothing in this space models them deeper.
- You want open source you can read, fork, and contribute to, with a community around it.
- Super Scaffolding's code generation matches how you like to work.
Choose Uno if…
- You build with AI coding agents — AGENTS.md, per-feature docs, and pure-Ruby views are the point.
- You want one $6 server: no Redis to run, patch, and monitor next to Postgres.
- You want a wired deploy story (Kamal 2, SSL, storage) instead of assembling one.
- You value a single accountable author over a community queue when something breaks.
What do you actually trade for free?
Operating surface and accountability. Bullet Train's stack requires Redis for websockets and Sidekiq, an esbuild/PostCSS build chain, and an Avo admin — capable pieces, each one more thing to run, upgrade, and debug. Support is a Discord and a GitHub issue queue, which can be excellent and can also be silence. Uno costs money and gives you the opposite trade: PostgreSQL as the only datastore, a deploy that is already wired, and one author whose own products break first if the template does.
Why does the view layer matter for AI-assisted work?
Bullet Train uses ERB with its Nice Partials engine — familiar to every Rails developer, and as of July 2026 it ships no AI-agent tooling or conventions. Uno's views are Phlex: plain Ruby objects a coding agent edits with the same accuracy as any other Ruby class, at a fraction of the token cost of HTML templates. Add AGENTS.md and a doc per feature, and the practical result is that Claude Code or Cursor follows Uno's conventions instead of inventing structure.
Different products for different shapes
Bullet Train's founding thesis is that teams are an MVP feature — if your product is team-shaped B2B, that head start is real and Uno does not attempt to match it. Uno's thesis is that the boring 90% — auth, billing, admin, jobs, deploys — should be production-hardened and agent-legible so a solo founder ships this weekend. Pick by the product you are building, not by the price tag.
See what Uno ships
The full feature tour, stack rationale, and one-time pricing: