The short answer
Browserbase provides managed browsers and the MIT-licensed Stagehand SDK. Steel offers a managed cloud and an Apache-2.0 browser core you can self-host. Kernel offers managed browsers and Apache-2.0 browser images you can run yourself. Choose by deployment requirements, billing units and session workflows. SOTA’s assessment is documentation-based.
| Decision | Browserbase | Steel | Kernel |
|---|---|---|---|
| Hosting and licence | Managed cloud; no on-prem deployment. Stagehand SDK: MIT | Managed cloud or self-hosted Steel Browser core: Apache-2.0 | Managed cloud or runnable kernel-images browser images: Apache-2.0 |
| Starting allowance | Free: 1 browser hour per month | Launch: $0/month plus usage; $30 one-time credits, valid for 90 days | Free: $0/month plus usage; $5 monthly credits |
| Free-plan capacity and retention | 3 concurrent browsers; 15-minute sessions; 7-day data retention | Launch: 10 concurrent sessions; 15-minute sessions; 7-day data retention | 5 concurrent browsers; 1-day replay retention; idle timeout described below |
| Paid subscription entry | Developer: $20/month, 100 browser hours and 1 GB proxy bandwidth | Scale: $250/month plus usage, with $100 monthly credits; Launch already supports paid usage | Hobbyist: $30/month plus usage, with $10 monthly credits |
| Browser and proxy billing | Developer overages: $0.12/browser hour and $12/GB proxy bandwidth | Launch: $0.10/browser hour, $10/GB proxies; Scale: $0.08/hour, $6/GB | Active runtime: $0.0000166667/GB-second; no idle-time or proxy charges |
| Documented interfaces | Playwright, Puppeteer, Selenium, CDP, Stagehand, Browser Use; hosted or local MCP server; Python and Node.js SDKs | Playwright, Puppeteer, Selenium, CDP, Stagehand, Browser Use; MCP server cookbook; Python and Node.js SDKs | Playwright execution, Playwright/Puppeteer over CDP, Stagehand, Browser Use; hosted MCP server; TypeScript, Python and Go SDKs |
Managed cloud or your own browser infrastructure
Browserbase provides managed cloud browsers and says it does not offer on-prem deployment. Stagehand is its automation SDK, with an MIT licence in its GitHub repository. That SDK licence is separate from the hosted Browserbase service.
Steel offers a managed cloud and the self-hostable Steel Browser core under Apache-2.0. Its repository documents Docker deployment. Kernel also provides managed cloud browsers; its kernel-images repository is Apache-2.0 and documents running the browser image in Docker or on a Unikraft unikernel. These repositories provide components you can run yourself; compare their documented features with the managed services before choosing self-hosting.
Allowances, subscriptions and usage charges
Browserbase Free includes 1 browser hour each month, 3 concurrent browsers, a 15-minute maximum session and 7-day data retention. Developer costs $20 per month and includes 100 browser hours and 1 GB of proxy bandwidth, then charges $0.12 per browser hour and $12 per GB. The docs bill browser time by the minute and proxy traffic by the MB, with a one-minute and one-MB minimum per session. Pricing lists automatic CAPTCHA solving on paid plans and none on Free. It lists no stealth mode on Free, Basic stealth on Developer and Startup, and Advanced stealth on Scale.
Steel Launch has a $0 monthly subscription fee plus usage. Its $30 credit grant is one-time, expires after 90 days and covers metered usage. Launch allows 10 concurrent sessions, sessions up to 15 minutes and 7-day data retention. Rates are $0.10 per browser hour, $10 per GB of proxy traffic and $3 per 1,000 CAPTCHA solves. Browser time is billed by the minute, rounded up. Launch requires $10 in paid balance to enable Steel-provided proxies and CAPTCHA solving; that deposit funds usage. Scale is $250 per month plus usage, with $100 monthly credits, $0.08 per browser hour, $6 per GB of proxies and $1 per 1,000 CAPTCHA solves. Usage beyond credits is billed at the plan’s rates.
Kernel Free has a $0 monthly platform fee plus usage, $5 monthly credits, 5 concurrent browsers and 1-day replay retention. Hobbyist costs $30 per month plus usage and includes $10 monthly credits. Active runtime costs $0.0000166667 per GB-second, with no idle-time or proxy charges. The docs list $0.0000166667 per second for a headless browser and $0.0001333336 per second for a headful browser. Credits apply to usage costs. Kernel’s timeout defaults to 60 seconds and can be set up to 72 hours; it starts when the browser enters standby. This is an idle deletion timeout, not a maximum total session duration.
Automation libraries, SDKs and MCP
Browserbase documents Playwright and Puppeteer connections, including CDP, plus Selenium, Stagehand and Browser Use. Its Browserbase SDKs cover Python and Node.js. Its Stagehand-based MCP server has a hosted Streamable HTTP endpoint and can also run locally over STDIO.
Steel documents Playwright and Puppeteer, Selenium through WebDriver, and integrations for Stagehand and Browser Use. Its SDKs cover Python and Node.js. Its MCP cookbook shows how to build a server that gives MCP clients a Steel cloud session.
Kernel documents Playwright execution inside the browser VM, connections from Playwright or Puppeteer over CDP, and integrations for Stagehand and Browser Use. Its SDK quickstart covers TypeScript, Python and Go. Its hosted MCP server can launch browsers, execute Playwright code and capture video replays.
State, inspection, files and security claims
Browserbase Contexts preserve cookies, authentication and application data between sessions. Its docs provide live views and session replay. Downloaded files sync to cloud storage and remain accessible through the API after the session completes. Its plan documentation states SOC 2 compliance.
Steel profiles preserve browser state across sessions. Its docs describe embedded live sessions and recorded-session playback, plus file uploads and downloads; session files are backed up when sessions end. Its pricing table reserves the Stealth Browser feature for Enterprise and states that Scale and Enterprise include a HIPAA-ready BAA.
Kernel profiles preserve cookies, site data, tabs and preferences. Free includes live view, replays and file uploads and downloads. Stealth mode adds a managed proxy and automatic CAPTCHA solver. Retrieve downloaded files before the browser is deleted or times out: its File I/O docs say those files are then permanently deleted. Its pricing documentation states SOC 2 compliance on all plans and HIPAA compliance with a BAA on Enterprise.
How to choose
SOTA’s assessment is documentation-based; it includes no hands-on testing or performance benchmarks. Consider Browserbase for managed browsers with Stagehand and a hosted MCP endpoint. Consider Steel when a self-hostable browser core matters, while budgeting separately for proxy traffic and CAPTCHA solves. Consider Kernel when you want in-VM Playwright execution and billing tied to active runtime and browser memory. Estimate your own session duration, concurrency, proxy traffic and browser type, then check retention and download handling against your workflow.
Sources & method
Official documentation was checked on 2026-10-12. Selection advice is our assessment. Interfaces and requirements may change; check the linked source for the version you intend to use.
- Browserbase pricing, hosting and plan features
- Browserbase plan allocations, billing units and security claims
- Stagehand MIT licence
- Browserbase automation connections, live view and replay
- Browserbase SDK languages
- Browserbase Browser Use integration
- Browserbase MCP server
- Browserbase persistent contexts
- Browserbase file storage and downloads
- Steel pricing, credits, limits and billing
- Steel Browser deployment, integrations and SDKs
- Steel Browser Apache-2.0 licence
- Steel Playwright over CDP
- Steel Selenium over WebDriver
- Steel Stagehand integration
- Steel Browser Use integration
- Steel MCP server cookbook
- Steel persistent profiles
- Steel live and recorded session embeds
- Steel file management
- Kernel pricing and starting allowances
- Kernel usage rates, credits, replay retention and security claims
- Kernel browser image deployment
- Kernel browser images Apache-2.0 licence
- Kernel idle deletion timeouts
- Kernel browser control interfaces
- Kernel Stagehand and Browser Use integrations
- Kernel SDK languages
- Kernel hosted MCP server
- Kernel persistent profiles
- Kernel managed stealth proxy and CAPTCHA solver
- Kernel downloads and file deletion
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