# Open-source Cubic alternative: J-Bot Review

Updated July 4, 2026 · plan structure checked against docs.cubic.dev on this date

**J-Bot Review is an open-source (MIT) alternative to Cubic that runs inside your own GitHub Actions instead of a hosted service.** It reviews with a model you already pay for, posts diff-anchored findings that a second model verifies before they land, and adds **$0 per seat with no reviewed-line metering**. Cubic is a hosted reviewer billed per seat with usage measured in reviewed lines; its per-seat prices aren't published in machine-readable form, so this page sticks to the plan structure their docs describe.

## Side by side

|  | Cubic | J-Bot Review |
| --- | --- | --- |
| price | Seat-based (per-seat prices not published in their docs — see cubic.dev/pricing); permanent free plan with 20 AI reviews/org/month; 7-day trial; annual billing at 20% off | $0 per seat, MIT license — you pay only your model provider (or $0 with OpenCode Zen free models / a CLI seat you already pay for) plus CI minutes |
| metering | Reviewed lines, pooled across paid seats; complex-PR Ultrareviews count 3×; overage $30 per 10,000 extra lines | None — full base…head diff on every PR, bounded by your model plan and CI |
| where it runs | Cubic's hosted service | Your GitHub Actions runner, as a container action |
| code path | Your code is processed by their service and the models it operates | Read-only checkout on your runner; the diff goes only to the model you configure, on your own key |
| model choice | Vendor-managed (their docs don't describe bring-your-own-model) | 30+ backends: OpenCode gateways (Claude, OpenAI, Gemini, DeepSeek…) or CLI seats (Codex, Cursor, Devin, Cline, Kilo, Command Code, Grok Build, Qoder) |
| beyond review | Analytics, issue-tracker integrations, background agents, PR management | Focused on PR review: verified findings, house-rules pass, live-docs checks (Context7), `/jbot` re-review command |
| config files | Product-managed settings | Reads `AGENTS.md`, `REVIEW.md`, `.coderabbit.yaml`, `greptile.json`, Cursor rules from your repo |
| source | Proprietary | Open source (MIT), on the [GitHub Marketplace](https://github.com/marketplace/actions/j-bot-code-review) |

Plan structure from [docs.cubic.dev](https://docs.cubic.dev/account/subscription), checked 2026-07-04; per-seat prices live at [cubic.dev/pricing](https://www.cubic.dev/pricing) — verify there.

## When Cubic is the better choice

- You want a **permanent free plan with zero setup** — 20 AI reviews a month for the whole organization, no CI configuration, no secrets to manage.
- You value the **product around the review**: hosted analytics, issue-tracker integrations, background agents, PR management.
- You'd rather have **predictable seat billing with pooled usage** than manage a model budget yourself.

## When J-Bot Review is the better choice

- **Your code can't go through a hosted service.** The review runs on your runner; only the diff reaches the model you chose, on your own account.
- **Line metering doesn't fit your PR volume.** No reviewed-line counters, no 3× surcharges for complex PRs — a big refactor costs whatever your model plan says it costs, which can be $0 on free models or an existing CLI seat.
- **You want to pick the model** and switch it with one repo variable as the frontier moves.
- **You want to audit your reviewer.** MIT-licensed action you can read, pin, and fork.

> **Migration note**
>
> Nothing to port — put your review guidance in `AGENTS.md` or `REVIEW.md` and J-Bot picks it up automatically. Add [one workflow file and one secret](https://www.pgupai.com/#setup), run both reviewers side by side on a few PRs, and keep whichever posts the findings you trust.

## FAQ

### What does Cubic cost compared to J-Bot Review?

Cubic is seat-based with usage metered in reviewed lines, pooled across paid seats; overage is $30 per 10,000 extra reviewed lines, complex-PR Ultrareviews count at 3× the standard rate, and there is a permanent free plan with 20 AI reviews per organization per month plus a 7-day trial. Per-seat dollar prices are not published in their docs — check cubic.dev/pricing. As of July 2026. J-Bot Review is an MIT-licensed action with no seats and no line metering: you pay only the model you bring (which can be $0 with OpenCode Zen free models or a coding-CLI seat you already pay for) plus normal CI minutes.

### Does J-Bot Review meter reviews or reviewed lines?

No. There is no review count, credit, or reviewed-line metering in J-Bot Review — the full base-to-head diff of every PR is reviewed, bounded only by your model plan's own limits and your CI minutes. Large PRs can be sharded for speed, and doc-only PRs are skipped without a model call.

### When is Cubic the better choice?

If you want a managed product with a permanent free plan (20 reviews per month for the whole organization), hosted analytics, issue-tracker integrations, and background agents — with zero CI configuration — Cubic is a straightforward hosted option. J-Bot Review is the fit when you want the reviewer inside your own GitHub Actions, on your own keys or CLI seats, at $0 per seat, with the model your choice.

## Related

- **Compare** — [CodeRabbit alternative](https://www.pgupai.com/compare/coderabbit-alternative): The same side-by-side, for CodeRabbit.
- **Guide** — [Review PRs with a CLI subscription](https://www.pgupai.com/guides/cli-subscription-code-review): Codex, Cursor, Devin, Cline, Kilo, Command Code, Grok Build, Qoder — reuse the seat you pay for.
- **Example** — [See a real review](https://www.pgupai.com/#proof): A verified blocking finding, on a real diff.

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