Quizlet is gatekeeping more and more, so i made an extension

This script gives an average time of about 3.5 seconds. If you need to be even faster you can tune the settings at the top of the script. But be aware that at a specific speed Quizlet doesn't accept the result because it's too fast.

(async () => {
  // ===== config =====
  const CLICK_DELAY_MS = 120;   // delay between the two clicks of a pair
  const PAIR_DELAY_MS  = 250;   // delay after a completed pair
  const START_WAIT_MS  = 1500;  // wait for board to appear after clicking start
  const MAX_ITERS      = 500;   // safety stop
  // ==================

  const C = 'color:#7F77DD;font-weight:bold';
  const log  = (m, ...a) => console.log(`%c[Match]%c ${m}`, C, '', ...a);
  const warn = (m, ...a) => console.warn(`%c[Match]%c ${m}`, C, '', ...a);
  const err  = (m, ...a) => console.error(`%c[Match]%c ${m}`, C, '', ...a);
  const sleep = ms => new Promise(r => setTimeout(r, ms));
  const norm = s => (s || '').trim().toLowerCase().replace(/\s+/g, ' ');

  const realClick = (el) => {
    const r = el.getBoundingClientRect();
    const o = { bubbles: true, cancelable: true, view: window,
                clientX: r.left + r.width/2, clientY: r.top + r.height/2 };
    el.dispatchEvent(new PointerEvent('pointerdown', { ...o, pointerType: 'mouse' }));
    el.dispatchEvent(new MouseEvent('mousedown', o));
    el.dispatchEvent(new PointerEvent('pointerup',   { ...o, pointerType: 'mouse' }));
    el.dispatchEvent(new MouseEvent('mouseup', o));
    el.dispatchEvent(new MouseEvent('click', o));
  };

  const isVisible = (el) => {
    if (!el?.isConnected) return false;
    const r = el.getBoundingClientRect();
    if (r.width < 1 || r.height < 1) return false;
    const cs = getComputedStyle(el);
    return cs.visibility !== 'hidden' && cs.display !== 'none' && parseFloat(cs.opacity) > 0.1;
  };

  // 1. extract set id
  const m = location.pathname.match(/^\/(?:[a-z]{2}\/)?(\d+)(?:\/|$)/);
  if (!m) { err('Could not parse set ID from URL'); return; }
  const setId = m[1];
  log(`Set ID: ${setId}`);

  // 2. fetch cards (paginated)
  log('Fetching cards...');
  const cards = [];
  let page = 1, pagingToken = '';
  const perPage = 200;
  while (true) {
    const qs = new URLSearchParams({
      'filters[studiableContainerId]': setId,
      'filters[studiableContainerType]': '1',
      perPage: String(perPage),
      page: String(page),
    });
    if (pagingToken) qs.set('pagingToken', pagingToken);

    const res = await fetch(`https://quizlet.com/webapi/3.4/studiable-item-documents?${qs}`, { credentials: 'include' });
    if (!res.ok) { err(`API returned ${res.status}`); return; }
    const data = await res.json();
    const resp = data?.responses?.[0];
    const items = resp?.models?.studiableItem || [];

    for (const it of items) {
      const term = it.cardSides?.[0]?.media?.find(x => x.plainText)?.plainText;
      const def  = it.cardSides?.[1]?.media?.find(x => x.plainText)?.plainText;
      if (term && def) cards.push({ term, def });
    }

    const total = resp?.paging?.total;
    pagingToken = resp?.paging?.token || '';
    if (items.length < perPage || (total != null && cards.length >= total)) break;
    page++;
  }
  log(`Got ${cards.length} cards`);
  if (!cards.length) { err('No cards fetched'); return; }

  // build pair lookup: each side knows its partner
  const pair = new Map();
  for (const { term, def } of cards) {
    pair.set(norm(term), norm(def));
    pair.set(norm(def), norm(term));
  }

  // 3. click start button inside #__next
  const root = document.getElementById('__next');
  if (!root) { err('#__next not found'); return; }

  const startRx = /spiel beginnen|start game|jouer|commencer|begin game|empezar|iniciar|gioca/i;
  let startBtn = [...root.querySelectorAll('button')].find(b => {
    const lab = (b.getAttribute('aria-label') || '') + ' ' + (b.textContent || '');
    return startRx.test(lab);
  });
  if (!startBtn) startBtn = root.querySelector('button[data-testid="assembly-button-primary"]');

  if (startBtn) {
    log(`Clicking start: "${(startBtn.getAttribute('aria-label') || startBtn.textContent || '').trim()}"`);
    realClick(startBtn);
    await sleep(START_WAIT_MS);
  } else {
    warn('No start button found (assuming game already running)');
  }

  // 4. matching loop
  const getTiles = () => {
    const nodes = root.querySelectorAll('.FormattedText[aria-label]');
    const out = [];
    for (const n of nodes) {
      // FormattedText -> .t1s3w3lt -> .c13hkcga -> tile container
      const tile = n.parentElement?.parentElement?.parentElement;
      if (!tile || !isVisible(tile)) continue;
      out.push({ tile, text: n.getAttribute('aria-label') || '' });
    }
    return out;
  };

  log('Matching started');
  let matched = 0, stuck = 0, prevCount = -1;

  for (let i = 0; i < MAX_ITERS; i++) {
    const tiles = getTiles();

    if (tiles.length === 0) {
      log(`%c✓ Done. Matched ${matched} pairs.`, 'color:#1D9E75;font-weight:bold');
      return;
    }

    if (tiles.length === prevCount) {
      if (++stuck > 3) { err('Stuck. Remaining:', tiles.map(t => t.text)); return; }
    } else { stuck = 0; prevCount = tiles.length; }

    // map normalized text -> DOM tile (for currently visible tiles)
    const visible = new Map();
    for (const t of tiles) {
      const k = norm(t.text);
      if (!visible.has(k)) visible.set(k, t.tile);
    }

    // find first tile whose partner is also visible
    let A, B, aTxt, bTxt;
    for (const t of tiles) {
      const partner = pair.get(norm(t.text));
      if (partner && visible.has(partner) && visible.get(partner) !== t.tile) {
        A = t.tile; aTxt = t.text;
        B = visible.get(partner); bTxt = partner;
        break;
      }
    }

    if (!A) {
      warn('No pair found among visible tiles:', tiles.map(t => t.text));
      await sleep(400);
      continue;
    }

    matched++;
    log(`${matched}. "${aTxt}"  ↔  "${bTxt}"`);
    realClick(A);
    await sleep(CLICK_DELAY_MS);
    realClick(B);
    await sleep(PAIR_DELAY_MS);
  }

  err(`Hit max iterations (${MAX_ITERS})`);
})();