Please excuse my sub-par JavaScript, I am a backend dev.

All you need to do is paste this into Tampermonkey and enter your username and your instance url (on two locations).

This is not showing other users’ scores and it doesn’t make your score visible to anyone else than yourself.

So no need for karma farming. This is just for fun.

// ==UserScript==
// @name         Lemmy score
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Shows your total post/comment score at the top right.
// @author       You
// @match        ENTER INSTANCE URL HERE (leave the asterisk after the URL)*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=feddit.de
// @grant        none
// @run-at       document-idle
// ==/UserScript==

(function() {
    'use strict';

    var USERNAME = "ENTER USERNAME HERE";
    var INSTANCE_URL = "ENTER INSTANCE URL HERE";

    var totalScore = 0;
    var currentPage = 1;

    function postResult() {
        var navbar = document.getElementsByClassName("collapse navbar-collapse")[0];
        console.log(navbar);
        var ul = document.createElement("ul");
        ul.className = "navbar-nav";
        ul.id = "karma-ul";
        var li = document.createElement("li");
        li.id = "karma-li";
        li.className = "nav-item";
        li.innerHTML = '<div id="karma-div">' + totalScore + '</div>'
        navbar.appendChild(ul);
        ul.appendChild(li);
    }
    function callPage() {
        var userRequest = new XMLHttpRequest();
        userRequest.onreadystatechange = function () {
            if (this.readyState == 4) {
                if (this.status == 200 ) {
                    var res = JSON.parse(this.responseText);
                    if (res.posts.length==0 && res.comments.length==0) {
                        postResult();
                    } else {
                        totalScore += res.posts.map(x => x.counts.score).reduce((partialSum, a) => partialSum + a, 0);
                        totalScore += res.comments.map(x => x.counts.score).reduce((partialSum, a) => partialSum + a, 0);
                        currentPage++;
                        callPage();
                    }
                }
            }
        }
        userRequest.open("GET", INSTANCE_URL + "/api/v3/user?username=" + USERNAME + "&limit=50&page=" + currentPage, true);
        userRequest.send();
    }

    setTimeout(callPage, 200);
})();