The CLI supports three output formats, controlled by the --format flag.

JSON (default)

Structured JSON output, suitable for scripts and programmatic consumption:

opensea collections get mfers

{
  "collection": "mfers",
  "name": "mfers",
  "description": "mfers are generated entirely from hand drawings by sartoshi...",
  "image_url": "https://i.seadn.io/...",
  "owner": "0x..."
}

Table

Human-readable tabular output for terminal use:

opensea --format table collections stats mfers

For arrays of objects, the table format renders rows and columns:

opensea --format table listings best mfers --limit 3

TOON

Token-Oriented Object Notation is a compact format that uses approximately 40% fewer tokens than JSON. It is designed for piping output into LLM and AI agent context windows where token efficiency matters.

opensea --format toon tokens trending --limit 3

Example TOON output:

tokens[3]{name,symbol,chain,market_cap,price_usd}:
  Ethereum,ETH,ethereum,250000000000,2100.50
  Bitcoin,BTC,bitcoin,900000000000,48000.00
  Solana,SOL,solana,30000000000,95.25
next: abc123

TOON collapses uniform arrays of objects into CSV-like tables with a single header row. Nested objects use YAML-like indentation. The encoder follows the TOON v3.0 spec.

Programmatic TOON Usage

TOON is also available programmatically via the SDK:

import { OpenSeaCLI, formatToon } from "@opensea/cli"

const client = new OpenSeaCLI({ apiKey: process.env.OPENSEA_API_KEY })
const data = await client.tokens.trending({ limit: 5 })
console.log(formatToon(data))

Field Filtering

Use --fields to limit output to specific fields:

opensea --fields name,floor_price collections stats mfers

This works with all output formats and is applied before formatting.

Line Truncation

Use --max-lines to limit the number of output lines:

opensea --max-lines 20 nfts list-by-collection mfers --limit 50

This is applied after formatting and is useful for keeping output manageable in terminal sessions or agent context windows.