To get the latest prices, you can use:
https://api.huobi.pro/market/trade?symbol=btcusdt
{"ch":"market.btcusdt.trade.detail","status":"ok","ts":1636430996365,"tick":{"id":141243356294,"ts":1636430996153,"data":[{"id":141243356294406904906517411,"ts":1636430996153,"trade-id":102555243865,"amount":0.005594,"price":68284.01,"direction":"buy"}]}}
To get the depth, you can use:
https://api.huobi.pro/market/depth?symbol=btcusdt&type=step1
{"ch":"market.btcusdt.depth.step1","status":"ok","ts":1636431051579,"tick":{"bids":[[68295.9,0.120818],[68293.2,0.2],[68290.5,0.04992],[68289.7,0.2],[68288.2,0.259111],[68288.1,0.1],[68287.5,0.01],[68287.2,0.120919],[68286.8,0.001464],[68285.0,0.2],[68283.8,0.002419],[68283.7,0.004837],[68281.4,0.2],[68280.2,0.00732],[68280.0,0.008036],[68278.4,0.015],[68277.0,0.004876],[68275.9,0.018194],[68275.8,0.073161],[68274.2,1.500967]],"asks":[[68296.0,0.385628],[68296.1,0.014631],[68297.7,0.100889],[68298.0,0.005074],[68300.0,0.005185],[68300.2,0.4],[68301.5,0.073157],[68302.8,0.19],[68303.6,0.487816],[68305.5,0.1],[68307.7,0.4],[68307.9,1.11],[68308.4,0.0187],[68308.7,0.015],[68309.2,0.194342],[68310.3,1.121419],[68314.5,1.526117],[68315.8,0.11],[68317.8,0.146459],[68318.1,0.5]],"version":141243384400,"ts":1636431051004}}
These APIs don't require API keys, but it has 10 calls / second limit.