Broadcast raw transaction without input validation

Question

What tool/software can I use to broadcast a raw transaction, which would not reject a transaction because of invalid or double spend?

Bitcoind with RPC has a validation step which rejects any raw transaction where the inputs are not known, or if the inputs are double spending.

Also, I don't want to rely on a third party service like blockchain.info.

Answer 1

Turns out there are many ways to do this:

• Node.js: Bitcore lets you broadcast a raw transaction to the network without any kind of validation, see the "broadcast a transaction through P2P" example.
• Python: Protocoin is a library that can do that.
• Java: BitcoinJ can do it.
• C#: Bitcoincsharp, which is a port of BitcoinJ can also do it.

Answer 2

There is absolutely no reason trying to broadcast invalid transaction. It is wasting your time and your traffic. Your peer(s) will check it and throw it away. They will not relay it to network. They also can ban your IP-address for some time (1 day?)

May be you want to send valid but non-standard transaction? Or may be you want to have a custom tool, which sends transactions to a network?

    // [...]
    void NetSocket::pushTx ( const QByteArray& data )
    {
      const MyKey32 key ( data.constData ( ), data.size ( ) );  // calculate txid
      outTx.insert ( key, data );                               // store data
      write ( "inv", invPacket ( MSG_TX, key ) );               // send inv packet
    }
    //--------------------------------------------------------------
    void NetSocket::write ( const char* type, const QByteArray& data )
    {
      socket -> write ( packet ( type, data ) );
    }
    //--------------------------------------------------------------
    void NetSocket::procGetdataPacket ( const QByteArray& data )
    {
      Stream d ( data ); d.skip24 ( );               // i do not check header now
      const int count ( d.readVar ( ) );
      xassert ( count == 1 );
      const quint8* ss = d.readAdvance ( 36 );
      const quint32 tag ( *(quint32*)ss );
      const MyKey32 key ( ss + 4 );
      xassert ( tag == MSG_TX );
      xassert ( outTx.contains ( key ) );
      write ( "tx", txPacket ( outTx.value ( key ) ) );
    }
    // [...]