Browser platforms / Smooth alternative

A Smooth.sh alternative

Smooth is a browser-automation agent at smooth.sh. It can execute a one-shot task or keep several tasks in one browser session, and profiles carry authentication into future work. Compare that managed web-agent interface with the Linux runtime that owns your broader agent application.

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Reviewed 2026-10-18 · Published by the Sandbox0 team

When Smooth fits

Smooth fits browser tasks where natural-language execution, extraction and interactive session workflows reduce orchestration work. Its saved profiles can reduce repeated logins, subject to the target site’s authentication behavior.

When to consider Sandbox0

Consider Sandbox0 when the agent must also install system tools, run code and services, retain configuration and grow its complete writable RootFS. You choose and integrate the browser agent or automation engine rather than assuming raw runtime compute includes managed web-agent steps.

Capabilities

Smooth and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeSmoothNot established in this reviewSandbox0ttl and hard_ttl default to 0 (disabled). Configure idle pause and deletion policies for the same persistent sandbox identity; an idle running sandbox still accrues compute charges.Read documentation →
Persistent filesSmoothProfiles retain browser state; an independently managed durable Linux disk is not established.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSSmoothBrowser profile reuse does not establish complete Linux RootFS persistence.View evidence ↗Sandbox0Persistence extends beyond /workspace to paths such as /usr/local, /etc, and /home. Runtime tmpfs and virtual filesystems are excluded.Read documentation →
Release compute, keep stateSmoothMulti-task live sessions and saved profiles do not establish a compute-free machine checkpoint.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateSmoothArbitrary process-memory restore is not established.View evidence ↗Sandbox0Experimental memory checkpoints can preserve compatible process state. Use memory: true on both pause and resume on a compatible deployment. A filesystem checkpoint alone does not preserve running processes.Read documentation →

Online RootFS growth

On growth-enabled images, Sandbox0 automatically expands the writable RootFS as free space runs low, within a configured sparse logical ceiling up to 64 TiB. Agent processes keep running. Growth is enabled in the qualified Cloud region; confirm activation for other regions. Existing images and snapshots retain their captured storage geometry. The ceiling is logical capacity, not preallocated host disk.

Smooth’s saved browser profiles and plan credits do not establish online expansion of a complete customer-controlled Linux filesystem. Sandbox0 retains the surrounding system configuration and installed tools as part of its durable writable RootFS.

Files while compute is paused

Sandbox0's Files API reads persistent files without resuming compute. Filesystem-only pauses also permit edits; retained-memory pauses are read-only and reject mutations with 409. SSH, SFTP, file watching, and runtime-only mounts require running compute.

Managing Smooth profiles is not a documented Files API for a paused Linux agent environment. Retain task outputs and supporting files in an explicit durable runtime or storage destination.

See paused file operations →

Several tasks can share one live browser

The Session method supports sequential agent tasks, deterministic navigation and extraction within a browser instance. Closing a session saves eligible profile changes; profile_read_only avoids writing them back. Keep the live session lifecycle separate from the state a later task reloads.

Source 1 ↗

Profiles persist authentication rather than a Linux installation

A profile must be created before attaching its ID to a session or task. This preserves browser authentication across tasks. It does not establish retention of arbitrary system packages, daemons, RAM or the whole writable filesystem surrounding an agent.

Source 1 ↗

Current public sources disagree on entry-plan capacity

The public pricing page lists ten concurrent Starter browsers, while the documentation’s plan table lists five. Both list $50/month, $50 of included credits and $0.005 per agent step. Confirm the effective concurrency and billing terms before designing a production queue; do not silently select the more generous number.

Source 1 ↗Source 2 ↗

Pricing

Compare billing models, then price your workload

CPU allocation, memory, billing minimums, disk, plan fees, and supported workload differ. These meters are not equal-performance machine quotes. Confirm region, resource units, and included allowances before estimating a total.

Smooth

Pricing reviewed 2026-10-18

Free agent-step rate
$0.005 per agent step
Two concurrent browsers; the site advertises welcome credits without a numeric amount.
Rate source ↗
Starter
$50/month including $50 API credits
Same $0.005 step rate. Site lists 10 concurrent browsers; the docs list 5.
Rate source ↗
Growth
$500/month including $500 API credits
50 concurrent browsers and the published $0.005 step rate.
Rate source ↗
Enterprise
Custom contract
Deployment, concurrency and usage terms require the contract; advertised unlimited labels are not a bounded Linux resource quote.
Rate source ↗

The docs publish $5 free credits but the current public pricing card leaves that amount unspecified, so no guaranteed welcome amount is assumed here. Included credits and agent steps are not a price per completed workflow or Linux compute-hour. Verify plan concurrency, credit expiry and any additional charges against your current account terms.

Check current Smooth pricing ↗

Sandbox0

$0.015/GiB-hour compute (billed by the second at approximately $0.000004167/GiB-second), plus $0.02/GiB-month of retained incremental RootFS and memory checkpoint data. Shared base images and platform recovery retention are excluded; paused sandboxes accrue storage charges only.

Compute / GiB-hour
$0.015
Retained data / GiB-month
$0.02
Paused compute
$0.00

A 4 GiB agent, 100 running hours

$6.00 compute

4 GiB × 100 hours, billed by the second. Keeping 20 GiB of billable incremental data for a full billing month adds $0.40. CPU is derived from memory by the platform; choose a tier that fits your workload.

Understand storage billing →

Before migrating from Smooth

  1. Inventory task/session methods, authentication profiles, current plan concurrency and actual agent steps per useful result.
  2. Run compatible agent orchestration and Linux tools on Sandbox0 while keeping Smooth as a web tool or porting browser actions explicitly.
  3. Validate profile save/read-only behavior, concurrency queuing, RootFS growth, paused files and full agent-step plus runtime costs.

Common questions

Is Sandbox0 a drop-in Smooth replacement?

Evaluate API compatibility and product scope. These products serve different core workflows, so a change may require a different architecture.

Does keeping files also keep a running agent?

Filesystem state and volatile process state are separate. Sandbox0 requires explicit compatible memory checkpoints to preserve running processes; its default filesystem resume starts fresh processes.

Sources and review scope

The Boat team's Battleships directory is the discovery source. References below describe the product and plan discussed on this page. Check current availability, regional terms and billing units before migrating. Where the cited material does not establish a capability or price, the comparison identifies that uncertainty.

Battleships research record ↗docs.smooth.sh/methods/session.md ↗docs.smooth.sh/methods/profiles.md ↗www.smooth.sh/pricing ↗docs.smooth.sh/pricing.md ↗Sandbox0 RootFS capacity →

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