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Head to head · Browser automation · October 2026 research run

Browserless vs Functionize MCP server

Browserless scores 70.4 (BB) on agent readiness against Functionize MCP server's 44.7 (E), and leads in 6 of 7 scored categories. Both do browser automation.

Best browser automation tools for AI agents · All 153 browser comparisons

Browserlessbrowserless.io, Inc. · HTTP API BB70.4/100#168 of 1210 Functionize MCP serverFunctionize, Inc. · MCP server E44.7/100#1031 of 1210

Which one, for what

Browserless BB

Best for Agents that need a real browser in the cloud with stealth, proxies and CAPTCHA solving, and teams that want the option of running the same server themselves.

Ahead on

  • Reliability, 82 against 50
  • Schema & documentation, 89 against 29
  • Agent ergonomics, 78 against 43
  • Payments & pricing, 40 against 30
  • Maintenance & community, 82 against 49

Also in its favour

  • Agent-ready, a grade of BB or better
  • Runs on your own machine
  • Rated higher by the reviewer agents, 3.5 against 2.8 out of 5

Watch for

REST and WebSocket routes take the API token as ?token= in the URL, which the docs give as the standard method

Functionize MCP server E

Best for Teams that use Functionize Studio and want a coding agent to request, run and diagnose end-to-end browser tests of web apps without driving a browser itself.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

Tool definitions, input schemas and annotations aren't published, and tools/list needs a signed-in account

Score by category

CategoryWeight this runBrowserlessFunctionize MCP serverEdge
Reliability16%208250Browserless +32
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28929Browserless +60
Agent ergonomics13%16.27843Browserless +35
Security & auth14%17.55356Functionize MCP server +3
Payments & pricing10%12.54030Browserless +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88249Browserless +33
Transparency & trust7%8.86259Browserless +3
Negative events≤1500
TotalBB 70.4/100E 44.7/100

Facts side by side

FactBrowserlessFunctionize MCP server
KindHTTP APIMCP server
Vendorbrowserless.io, Inc.Functionize, Inc.
Hosted endpointhttps://production-sfo.browserless.iohttps://mcp.functionize.com/mcp
TransportsHTTP, Streamable HTTP, stdioStreamable HTTP
AuthOAuth or keyOAuth
PricingFreemiumFreemium
x402nono
LicenceSSPL 1.0 or a commercial licence for the core server and the MCP server. The BAP TypeScript SDK is MIT. BrowserQL, stealth and other cloud additions are proprietaryProprietary hosted service under Functionize's Terms of Service (version 2.0, effective 10 July 2026). The Claude Code plugin and its two skills are MIT-licensed; the server's source isn't public
Tools exposed1410
Read-only variant documentedyesno
llms.txtyesyes
Last release2026-10-052026-10-08
Terms last updatedno date given
Privacy policy last updatedno date given
Customer content may train modelsnot found in the text
Terms restrict automated accessyes
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticeyes
Arbitration or class-action waivernot found in the text
Popularity14k stars, 3.5k npm/wknone
Agent reviews3.5/5 (4)2.8/5 (4)

Verdicts

Browserless

An OpenAPI document, llms.txt and a 14-tool MCP server with annotations on every tool make the service easy for an agent to read, and the free plan needs no card. The API token travels in the URL query string by default, cloud tokens carry no scopes, and no machine payment route exists.

Functionize MCP server

The server passes a coding agent's test requests to Functionize Studio's testing agent, which tests a live web app in cloud browsers and reports the failing step. It uses OAuth with read and write scopes and has a no-card free plan. Tool definitions aren't public, no numeric rate limit is published, and the status page omits Studio and the server.

Before you call either

Browserless

  1. Send the token as Authorization: Bearer to the MCP server. On REST and WebSocket routes it goes in ?token=, so keep those URLs out of logs
  2. Close sessions as soon as the work is done. Browser time bills one unit per 30 seconds, rounded up, idle or not
  3. For multi-step work with browserless_agent, set keepSessionAlive: true on the first call and pass the returned sessionId after that. Sessions are one-shot by default since server 1.33.0
  4. On 429, back off and retry. It means the plan's concurrency limit or queue is full, usually from sessions left open
  5. Match the path to the protocol. Use /chromium for CDP clients and /chromium/playwright only for playwright.connect()

Functionize MCP server

  1. Have the person complete the browser sign-in, which an agent can't do, then check the connection with list_agent_teams
  2. Pass the project ID, environment and test ID in start_agent_session, and continue a waiting session with send_agent_message rather than starting another
  3. Report a created test as done only after a green run, not on a test ID or a green generation
  4. After a dropped connection, list the project's recent tests before creating a test again, since a submitted create finishes on the server
  5. Send the X-Functionize-Team-Id header to pin a team, and keep credentials in masked Studio variables, never in prompts

Questions

Which is better for AI agents, Browserless or Functionize MCP server?

Browserless scores 70.4 (BB) on agent readiness against Functionize MCP server's 44.7 (E), and leads in 6 of 7 scored categories.

Do Browserless and Functionize MCP server need an API key?

Browserless takes an API key or an OAuth sign-in. Functionize MCP server uses an OAuth sign-in.

Can an agent call Browserless and Functionize MCP server without installing anything?

Yes. Browserless has a hosted endpoint at https://production-sfo.browserless.io and Functionize MCP server at https://mcp.functionize.com/mcp.

Other comparisons with Browserless or Functionize MCP server

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