Plasmate - Browser Engine for Agents#

Plasmate compiles HTML into a Semantic Object Model (SOM). 50x faster than Chrome, 10x fewer tokens.

• Docs: https://docs.plasmate.app
• Source: https://github.com/plasmate-labs/plasmate (Apache 2.0)
• Privacy: All processing runs locally. No telemetry or cloud services.

Install#

bash

# Build from source (recommended)
cargo install plasmate

# Or use the install script
curl -fsSL https://plasmate.app/install.sh | sh

Protocols#

• AWP (native): 7 methods - navigate, snapshot, click, type, scroll, select, extract
• CDP (compatibility): Puppeteer/Playwright compatible on port 9222

Default to AWP. Use CDP only when existing Puppeteer/Playwright code needs reuse.

Quick Start#

Fetch (one-shot, no server)#

bash

plasmate fetch <url>

Returns SOM JSON: regions, interactive elements with stable IDs, extracted content.

Server Mode#

bash

# AWP (recommended)
plasmate serve --protocol awp --port 9222

# CDP (Puppeteer compatible)
plasmate serve --protocol cdp --port 9222

AWP Usage (Python)#

Run scripts/awp-browse.py for AWP interactions:

bash

# Navigate and get SOM snapshot
python3 scripts/awp-browse.py navigate "https://example.com"

# Click an interactive element by ref ID
python3 scripts/awp-browse.py click "https://example.com" --ref "e12"

# Type into a field
python3 scripts/awp-browse.py type "https://example.com" --ref "e5" --text "search query"

# Extract structured data (JSON-LD, OpenGraph, tables)
python3 scripts/awp-browse.py extract "https://example.com"

# Scroll
python3 scripts/awp-browse.py scroll "https://example.com" --direction down

CDP Usage (Puppeteer)#

When CDP is needed, connect Puppeteer to the running server:

javascript

const browser = await puppeteer.connect({
  browserWSEndpoint: 'ws://127.0.0.1:9222'
});
const page = await browser.newPage();
await page.goto('https://example.com');
const content = await page.content();

SOM Output Structure#

SOM is a structured JSON representation, NOT raw HTML. Key sections:

• regions: Semantic page areas (nav, main, article, sidebar)
• interactive: Clickable/typeable elements with stable ref IDs (e.g., e1, e12)
• content: Text content organized by region
• structured_data: JSON-LD, OpenGraph, microdata extracted automatically

Use ref IDs from interactive elements for click/type actions.

Performance#

MetricPlasmateChromePer page4-5 ms252 msMemory (100 pages)30 MB20 GBOutput sizeSOM (10-800x smaller)Raw HTML

When to Use Plasmate vs Browser Tool#

• Plasmate: Speed-critical scraping, batch page processing, token-sensitive extraction, structured data
• Browser tool: Visual rendering needed, screenshots, complex JS SPAs requiring full Chrome engine, pixel-level interaction