Move your links from Bitly to Shortener.dev

This script reads every link in your Bitly account and creates the same link in Shortener.dev, keeping the back-half where it can. When it's done you have a CSV with the old Bitly link next to the new srt1.link link, so you can update your website, email templates and social bios.

Your existing bit.ly links keep pointing to Bitly. Nothing here changes them, and Shortener.dev can't take over the bit.ly domain. Click history also stays in Bitly. Export any reports you need before you close your Bitly account.

Before you start

• A Bitly access token. Create one in your Bitly account settings, under the API or developer section.
• A Shortener.dev API key, which is included on paid plans.
• Every destination domain verified in Shortener.dev, unless it's a whitelisted site like YouTube or Amazon. Links to unverified domains are skipped and listed in the CSV, so you can verify them and run the script again.
• Node.js 18 or later.
• Enough links left on your plan for the import. Each imported link counts toward your monthly limit.

The script

Save this as bitly-to-shortener.mjs:

import { existsSync, readFileSync, writeFileSync } from 'node:fs';

const BITLY = 'https://api-ssl.bitly.com/v4';
const SHORTENER = 'https://api.shortener.dev/v1/links';
const bitlyHeaders = { Authorization: `Bearer ${process.env.BITLY_TOKEN}` };
const shortenerHeaders = {
  Authorization: `Bearer ${process.env.SHORTENER_API_KEY}`,
  'Content-Type': 'application/json',
};
const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
const OUTPUT = 'bitly-to-shortener.csv';

// Links that worked in an earlier run, so a rerun doesn't create them twice
const done = new Map();
if (existsSync(OUTPUT)) {
  for (const line of readFileSync(OUTPUT, 'utf8').split('\n').slice(1)) {
    const cells = line.slice(1, -1).split('","');
    if (cells[2]) done.set(cells[0], cells);
  }
}

// 1. Read every Bitly link in the default group
const user = await fetch(`${BITLY}/user`, { headers: bitlyHeaders }).then((r) => r.json());
let next = `${BITLY}/groups/${user.default_group_guid}/bitlinks?size=100`;
const bitlinks = [];
while (next) {
  const page = await fetch(next, { headers: bitlyHeaders }).then((r) => r.json());
  bitlinks.push(...page.links);
  next = page.pagination?.next || null;
}
console.log(`Found ${bitlinks.length} Bitly links`);

// 2. Create each one in Shortener.dev, keeping the back-half when it's valid
const rows = [['bitly_link', 'long_url', 'new_link', 'error']];
for (const link of bitlinks) {
  if (done.has(`https://${link.id}`)) {
    rows.push(done.get(`https://${link.id}`));
    continue;
  }
  const backHalf = link.id.split('/').pop().toLowerCase();
  const body = { url: link.long_url };
  if (/^[a-z0-9_-]{2,32}$/.test(backHalf)) body.key = backHalf;
  if (link.title) body.title = link.title.slice(0, 60);

  let res = await fetch(SHORTENER, { method: 'POST', headers: shortenerHeaders, body: JSON.stringify(body) });
  let data = await res.json();

  // Back-half already taken: retry with a random one
  if (!res.ok && body.key && data.message?.includes('already been used')) {
    delete body.key;
    res = await fetch(SHORTENER, { method: 'POST', headers: shortenerHeaders, body: JSON.stringify(body) });
    data = await res.json();
  }

  rows.push([`https://${link.id}`, link.long_url, res.ok ? data.short_url : '', res.ok ? '' : data.message]);
  console.log(res.ok ? `${link.id} -> ${data.short_url}` : `${link.id} failed: ${data.message}`);
  await sleep(500); // stay under 150 requests a minute
}

// 3. Save the mapping
const csv = rows.map((row) => row.map((cell) => `"${String(cell ?? '').replace(/"/g, '""')}"`).join(',')).join('\n');
writeFileSync(OUTPUT, csv);
console.log(`Saved ${OUTPUT}`);

Run it with both keys in the environment:

BITLY_TOKEN=your-bitly-token SHORTENER_API_KEY=your-shortener-key node bitly-to-shortener.mjs

How back-halves carry over

Shortener.dev back-halves are lowercase, 2 to 32 characters, and use only letters, numbers, - and _. Bitly back-halves are case-sensitive, so bit.ly/Spring and bit.ly/spring both become srt1.link/spring. The second one hits "already been used" and gets a random back-half instead.

Back-halves are unique across all Shortener.dev accounts, so a popular word like sale may already be taken by someone else. Those links also get a random back-half. Check the new_link column in the CSV for the final URLs.

Links that fail

Look at the error column in bitly-to-shortener.csv:

• Domain not verified means you need to verify that domain. Verify it and run the script again in the same folder. Links that already have a new_link in the CSV are skipped, so only the failed ones are retried.
• Domain blocked means the destination is on a domain Shortener.dev doesn't allow, such as another link shortener or a free hosting service. If a Bitly link points to another short link, use the final destination instead.

Bitly-only features such as custom domains, link-in-bio pages and campaign data aren't copied. UTM parameters inside the long URL are kept as part of the URL.