Market Depth

/* GET /market/depth?symbol=ethusdt&type=step1 */
{
  "status": "ok",
  "ch": "market.btcusdt.depth.step1",
  "ts": 1489472598812,
  "tick": {
    "id": 1489464585407,
    "ts": 1489464585407,
    "mrid": 1489464585407,
    "version": 1489464585407,
    "ch": "market.btcusdt.depth.step1",
    "bids": [
      [7964, 0.0678], // [price, amount]
      [7963, 0.9162],
      [7961, 0.1],
      [7960, 12.8898],
      [7958, 1.2],
      [7955, 2.1009],
      [7954, 0.4708],
      [7953, 0.0564],
      [7951, 2.8031],
      [7950, 13.7785],
      [7949, 0.125],
      [7948, 4],
      [7942, 0.4337],
      [7940, 6.1612],
      [7936, 0.02],
      [7935, 1.3575],
      [7933, 2.002],
      [7932, 1.3449],
      [7930, 10.2974],
      [7929, 3.2226]
    ],
    "asks": [
      [7979, 0.0736],
      [7980, 1.0292],
      [7981, 5.5652],
      [7986, 0.2416],
      [7990, 1.9970],
      [7995, 0.88],
      [7996, 0.0212],
      [8000, 9.2609],
      [8002, 0.02],
      [8008, 1],
      [8010, 0.8735],
      [8011, 2.36],
      [8012, 0.02],
      [8014, 0.1067],
      [8015, 12.9118],
      [8016, 2.5206],
      [8017, 0.0166],
      [8018, 1.3218],
      [8019, 0.01],
      [8020, 13.6584]
    ]
  }
}

/* GET /market/depth?symbol=ethusdt&type=not-exist */
{
  "ts": 1490759358099,
  "status": "error",
  "err-code": "invalid-parameter",
  "err-msg": "invalid type"
}