A branch gets pushed late on a Friday, and before anyone opens the diff, a reviewer agent has cloned it, run the tests and posted a verdict. The coding agent reads the findings, pushes a fix, and the loop starts again. Nobody on the team has asked where that code actually ran.
Entire, the startup founded by former GitHub CEO Thomas Dohmke, has just made that question public: its Git Forge has review agents assess every push in cloud sandboxes, and Analytics India Magazine reports that the isolated environments come from Daytona and E2B. A team building the same loop needs a sandbox that starts fast, keeps state between rounds and clones a private repository safely, and Solari, E2B and Daytona all sell that machine with different defaults. This guide compares the three on fit, then on speed and cost.
What a Review Agent Needs From a Sandbox
The requirements come from the loop itself, so that is the place to start. Agent-driven code review means running code a model wrote minutes ago, so each push needs a fresh machine with a hard boundary around it.
Dohmke describes the goal as running "enough loops between your coding agent and the review agents" to reach a stable state. The environment therefore has to hold its files and processes between rounds and authenticate to a private Git remote without the credential landing on disk. Here is how each vendor answers those needs.
Solari
Solari runs sandboxes, browsers and desktops from one account and one API, which matters once a reviewer also has to check a running web page.
Pricing and plans. Solari's Free plan costs $0 a month with $3 of credits that refill monthly, and Starter is $20 a month. A team prototyping a review bot can run its first loops before it pays anything.
Where it fits. Each Solari sandbox gets a microVM of its own by default. Its git namespace clones, commits and pushes, and an access token travels as an environment variable of that command, never in the URL or the repository config. That is the exact shape of a reviewer that checks out a branch and pushes a fix.
Who it's best for. Solari suits teams whose agents loop many times on the same branch. Pausing a sandbox saves its memory and processes, and a running sandbox can be snapshotted and forked, so several reviewers can test different fixes from an identical starting point. When a review needs a screen, Solari desktops share the same lifecycle.
E2B
E2B is the first of the two vendors Entire chose, and its pricing is built around plans with concurrency caps.
Pricing and plans. E2B says its Hobby plan is free with a $100 one-time usage credit and sessions up to 1 hour, and its Pro plan is $150 a month plus usage, with sessions up to 24 hours and 100 concurrent sandboxes, on E2B's pricing page. A review fleet that outgrows that cap buys an add-on on top of Pro.
Where it fits. E2B is built for code execution by agents, and Pro lets a team set custom sandbox CPU and RAM. For a review loop that only runs tests and static checks, that focus is a direct match.
Trade-off. The Hobby session cap is short for a loop that waits on several review rounds, so production teams start on Pro. E2B says multi-day persistent sessions sit on Enterprise, with a $3,000 monthly minimum on the same pricing page.
Daytona
Daytona, the other half of Entire's setup, takes the opposite approach to pricing.
Pricing and plans. Daytona says it is pay-as-you-go with $200 in free compute and rates of $0.0504 per vCPU-hour and $0.0162 per GiB-hour of memory, billed per second, on Daytona's pricing page. Cost tracks the size of each review machine, and there is no plan fee.
Where it fits. Daytona offers container, Linux VM, Windows and GPU sandbox classes, according to its sandboxes docs. Its isolation page describes the VM class as a "Full virtual machine with its own kernel" that enables pause, resume, fork and hot snapshots.
Trade-off. Daytona's sandboxes page says "Sandboxes run as Linux containers by default", so a team that wants a hypervisor boundary around untrusted code picks the VM class on purpose. That default is worth checking before the first agent-written commit runs.
Speed and Cost for a Review Fleet
The table below sets the three side by side before the detail.
Speed matters because every review round waits for a machine to exist. Solari runs a sandbox's full lifecycle about 1.3x faster than E2B and about 1.7x faster than Daytona, a gap that repeats on every push.
Cost follows the same pattern. Solari's Professional plan rates sandboxes at $0.0245 per vCPU-hour and $0.0077 per GB-hour, against the Daytona rates above. E2B prices by the second, so the cleanest read across all three is the list price per sandbox hour in the closing section.
Choosing the Right Setup
The rule is to match the sandbox to the loop. A reviewer that runs tests once per push fits any of the three, while a loop that reviews, fixes and reviews again wants pause, snapshot and fork plus a credential that stays off disk. Choose E2B for its plan structure and code execution focus, and Daytona when no plan fee or GPU classes matter most. E2B and Daytona are the more established sandbox vendors and the ones Entire built on; Solari is the younger company and moves faster on speed and price.
Get Started With Solari
Start by pointing the review agent's next push at a Solari sandbox and letting it clone, test and push its fix through the git namespace. Solari is the fastest of the three on a sandbox's full lifecycle and almost 3x cheaper per sandbox hour than E2B and Daytona at list price, and the introduction to Solari shows how its three surfaces share an account. Create a first sandbox from the sandboxes guide and run the loop free.
