Anchor Browser (Action Index)

Launched October 15, 2026, Action Index is a shared memory of web workflows that AI agents on Anchor Browser have already completed successfully. Anchor provides secure, reliable cloud browsers that agents use to log in to, navigate and complete tasks on any website — including sites with no API. Instead of reasoning through every click from scratch, an agent replays a proven path as deterministic code, with the model stepping in only where a page has changed.

Key facts: on 300 tasks from the Online-Mind2Web benchmark, a small model with Action Index completed 93.3% of tasks at $0.016 per task — versus a frontier model at 93% for $1.57 per task. A full 300-task run cost $4.87 with Action Index vs $472 without. A paired 120-task study showed Action Index cutting 90th-percentile token use by 74%, steps by 75% and wall-clock time by 61%. Action Index is exposed via Anchor's MCP server (api.anchorbrowser.io/v1/mcp) and REST API, and works with any MCP-compatible agent or model provider.

Plans: genuinely free tier at $0/month — 5 credits/month, 0.1 credits per completed task (roughly 50 simple tasks), 5 concurrent browsers, 500 browser sessions, with Action Index included on all accounts including free. Starter $50/mo (+ $1.00/credit overage); Team, Growth and Enterprise are custom (Enterprise: 500+ concurrent browsers, SSO/RBAC, HIPAA/BAA/DPA, custom regions).

Best for: developers building AI agents that automate web workflows — SaaS builders unlocking integrations on sites with no API, service providers cutting automation costs, enterprises adopting AI securely. Available worldwide today; enterprise-grade security features (unique fingerprinting, zero-data-retention, bring-your-own-cloud) sit on paid tiers.

Related: Cursor · Perplexity

Pros

• Agents replay proven workflow paths as deterministic code instead of reasoning through every click from scratch.
• Strong benchmark results: 93.3 percent of 300 Online-Mind2Web tasks completed at $0.016 per task, versus a frontier model at 93 percent for $1.57 per task.
• A paired study showed large cuts in token use, steps and wall-clock time.
• Exposed via an MCP server and REST API, and works with any MCP-compatible agent or model provider.

Watch out for

• Replayed paths can break where a page has changed, and the model must then step in.
• Enterprise-grade security features such as zero-data-retention and bring-your-own-cloud sit on paid tiers.
• Credit-based pricing needs tracking on high-volume automation runs.

Best for

Developers building AI agents that automate web workflows, including SaaS builders unlocking integrations on sites with no API. Who should skip it: anyone who only needs a simple one-off scrape of a single site.

Pricing

Per the page's own text: a free tier at $0/month includes 5 credits a month, 5 concurrent browsers and 500 browser sessions, with Action Index included on all accounts; Starter is $50/month plus $1.00 per credit overage; Team, Growth and Enterprise are custom. Check the official pricing page for current terms.

FAQs

What is Action Index? A shared memory of web workflows that AI agents on Anchor Browser have already completed successfully.

How does it save cost? By replaying a proven path as code, so a small model can match a frontier model's success rate far more cheaply.

How do agents access it? Through Anchor's MCP server and REST API.

Is Action Index on the free tier? Yes, it is included on all accounts including free.