Validate 3rd party transactions on Bitcoin-qt debug window Is there a way to validate a random transaction via transaction ID on the debug window? Imagine I want to validate a transaction between 2 wallets I don't control. 

I believe its possible to check if such a transaction exists on the mempool "getmempoolentry" but can I also check the confirmations without having to decode a whole block like with "getrawtransaction"?
Finally figured it out.

Once you have your node up and running, make sure you synced with txindex enabled. If you already synced without it, you need to reindex with txindex=1 in your bitcoin.conf file. Restart and wait a couple of hours.

Once its re-synced, open the debug console and type:

getrawtransaction "TxID" true


Example:

getrawtransaction "bf585491b06630a94e06798fdfdf1809cc64741cd5bc0d41a50e69ba5b8ddbc5" true


This will return a decoded raw transaction like this: 

{
  "txid": "bf585491b06630a94e06798fdfdf1809cc64741cd5bc0d41a50e69ba5b8ddbc5",
  "hash": "bf585491b06630a94e06798fdfdf1809cc64741cd5bc0d41a50e69ba5b8ddbc5",
  "version": 1,
  "size": 225,
  "vsize": 225,
  "weight": 900,
  "locktime": 559545,
  "vin": [
    {
      "txid": "089fd283bc8e012eaa0203ebc40bb1b8888b2f0d0f0bac6664b26b250b15847c",
      "vout": 0,
      "scriptSig": {
        "asm": "304402206163b24284d24e03dc650a86e93d5dbec2dc7d66d4bf71f94ab03b147994160202202a236c07ff469ab2fa8aa2c416a467ad8845c2b5697c18ddabbda31ae7e6289e[ALL] 03e35ef46f9517547c2005c1c941c7651ecf59b44625d1239b78cc01eb2be7a72b",
        "hex": "47304402206163b24284d24e03dc650a86e93d5dbec2dc7d66d4bf71f94ab03b147994160202202a236c07ff469ab2fa8aa2c416a467ad8845c2b5697c18ddabbda31ae7e6289e012103e35ef46f9517547c2005c1c941c7651ecf59b44625d1239b78cc01eb2be7a72b"
      },
      "sequence": 4294967293
    }
  ],
  "vout": [
    {
      "value": 0.11233558,
      "n": 0,
      "scriptPubKey": {
        "asm": "OP_DUP OP_HASH160 48167b6d7c9ae260d2f1c494705f9557c89bc3c7 OP_EQUALVERIFY OP_CHECKSIG",
        "hex": "76a91448167b6d7c9ae260d2f1c494705f9557c89bc3c788ac",
        "reqSigs": 1,
        "type": "pubkeyhash",
        "addresses": [
          "17aAau6cUvT6WCWkwGWHiTqvsVKHfZowW5"
        ]
      }
    },
    {
      "value": 0.25392682,
      "n": 1,
      "scriptPubKey": {
        "asm": "OP_DUP OP_HASH160 c109fb3bab724bda053409ca9230f3a0f750aa22 OP_EQUALVERIFY OP_CHECKSIG",
        "hex": "76a914c109fb3bab724bda053409ca9230f3a0f750aa2288ac",
        "reqSigs": 1,
        "type": "pubkeyhash",
        "addresses": [
          "1JbhNYR96VG7Do6UZjrnrt3KaXrrrZzJ6i"
        ]
      }
    }
  ],
  "hex": "01000000017c84150b256bb26466ac0b0f0d2f8b88b8b10bc4eb0302aa2e018ebc83d29f08000000006a47304402206163b24284d24e03dc650a86e93d5dbec2dc7d66d4bf71f94ab03b147994160202202a236c07ff469ab2fa8aa2c416a467ad8845c2b5697c18ddabbda31ae7e6289e012103e35ef46f9517547c2005c1c941c7651ecf59b44625d1239b78cc01eb2be7a72bfdffffff021669ab00000000001976a91448167b6d7c9ae260d2f1c494705f9557c89bc3c788ac2a768301000000001976a914c109fb3bab724bda053409ca9230f3a0f750aa2288acb9890800",
  "blockhash": "00000000000000000023c227de45c3eb30b0f9727da4fee7b6e22b66c5d2b9da",
  "confirmations": 5,
  "time": 1548119868,
  "blocktime": 1548119868
}


Here you can verify confirmations of the transaction if you're checking for transactions from a third party to a cold wallet without having to trust online block explorers.