user86746: I am looking for the differences between the creation of Doge public keys and Bitcoin public keys when inserting a private key.
I am trying to make a small web-app that signs messages. There are a tons of them with bitcoin. They receive a private key and creates the public key from there. When I enter a Doge private key to the input the output is still a Bitcoin public key (Starts with 1 for example instead of D).

user60443: Dogecoin uses the same public key cryptography ECC with curve secp256k1, so public key generation is the same. 

When I enter a Doge private key to the input the output is still a
  Bitcoin public key (Starts with 1 for example instead of D).

You are confusing addresses with public keys. The 1 or the D is just a prefix to an address, depending on the type of address, see https://en.bitcoin.it/wiki/List_of_address_prefixes
After you generate the public key, you have to do the following in order to get an address:
BASE58CHECK(<address-prefix> HASH160(<pubKey>))
Dogecoin uses different prefixes for the different types of addresses, see https://github.com/dogecoin/dogecoin/blob/master/src/chainparams.cpp (note these are for mainnet only):
base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,30);  // 0x1e
base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,22);  // 0x16
base58Prefixes[SECRET_KEY] = std::vector<unsigned char>(1,158); // 0x9e

Changing the address prefixes should yield compatible addresses.

86746: <p>I am looking for the differences between the creation of Doge public keys and Bitcoin public keys when inserting a private key.</p>

<p>I am trying to make a small web-app that signs messages. There are a tons of them with bitcoin. They receive a private key and creates the public key from there. When I enter a Doge private key to the input the output is still a Bitcoin public key (Starts with 1 for example instead of D).</p>
 60443: <p>Dogecoin uses the same public key cryptography ECC with curve secp256k1, so public key generation is the same. </p>

<blockquote>
  <p>When I enter a Doge private key to the input the output is still a
  Bitcoin public key (Starts with 1 for example instead of D).</p>
</blockquote>

<p>You are confusing addresses with public keys. The 1 or the D is just a prefix to an address, depending on the type of address, see <a href="https://en.bitcoin.it/wiki/List_of_address_prefixes" rel="nofollow noreferrer">https://en.bitcoin.it/wiki/List_of_address_prefixes</a></p>

<p>After you generate the public key, you have to do the following in order to get an address:</p>

<p><code>BASE58CHECK(&lt;address-prefix&gt; HASH160(&lt;pubKey&gt;))</code></p>

<p>Dogecoin uses different prefixes for the different types of addresses, see <a href="https://github.com/dogecoin/dogecoin/blob/master/src/chainparams.cpp" rel="nofollow noreferrer">https://github.com/dogecoin/dogecoin/blob/master/src/chainparams.cpp</a> (note these are for mainnet only):</p>

<pre><code>base58Prefixes[PUBKEY_ADDRESS] = std::vector&lt;unsigned char&gt;(1,30);  // 0x1e
base58Prefixes[SCRIPT_ADDRESS] = std::vector&lt;unsigned char&gt;(1,22);  // 0x16
base58Prefixes[SECRET_KEY] = std::vector&lt;unsigned char&gt;(1,158); // 0x9e
</code></pre>

<p>Changing the address prefixes should yield compatible addresses.</p>
