Prioritizing BTC transactions using Bitcore APIs I’m planning to give a feature in my application where a user can select type of priority (Fast, Average or Slow) for their transactions. 

How can I get fee required for each type? Does Bitcore API provides any feature that handles priority of transactions?
This feature available on bitcoin-core RPC

bitcoin-cli help estimatesmartfee


estimatesmartfee conf_target ("estimate_mode")

Estimates the approximate fee per kilobyte needed for a transaction to begin
confirmation within conf_target blocks if possible and return the number of blocks
for which the estimate is valid. Uses virtual transaction size as defined
in BIP 141 (witness data is discounted).

Arguments:
1. conf_target     (numeric) Confirmation target in blocks (1 - 1008)
2. "estimate_mode" (string, optional, default=CONSERVATIVE) The fee estimate mode.
                   Whether to return a more conservative estimate which also satisfies
                   a longer history. A conservative estimate potentially returns a
                   higher feerate and is more likely to be sufficient for the desired
                   target, but is not as responsive to short term drops in the
                   prevailing fee market.  Must be one of:
       "UNSET" (defaults to CONSERVATIVE)
       "ECONOMICAL"
       "CONSERVATIVE"

Result:
{
  "feerate" : x.x,     (numeric, optional) estimate fee-per-kilobyte (in BTC)
  "errors": [ str... ] (json array of strings, optional) Errors encountered during processing
  "blocks" : n         (numeric) block number where estimate was found
}

The request target will be clamped between 2 and the highest target
fee estimation is able to return based on how long it has been running.
An error is returned if not enough transactions and blocks
have been observed to make an estimate for any number of blocks.

Example:

bitcoin-cli estimatesmartfee 6