The SNDR alternative to Loops.

Loops is a beautifully-designed marketing email tool with a transactional feature attached. For teams whose primary need is high-volume transactional infrastructure — order receipts, password resets, OTPs, system notifications — SNDR is a different shape of product: API-first, multi-MTA, observable per-box, with billing that does not assume a marketing team is in the loop.

Drawn from public documentation and pricing as of build time. We try to keep this fair — file an issue if anything is wrong.

1. 1

   Install the SDK

   Add @rkiza/sndr alongside loops. Both can run in parallel.

   pnpm add @rkiza/sndr

2. 2

   Replace the send call

   Loops sendTransactionalEmail maps to sndr.emails.send. transactionalId becomes template_id; dataVariables becomes variables.

   // before
   import { LoopsClient } from 'loops';
   const loops = new LoopsClient(process.env.LOOPS_API_KEY!);
   await loops.sendTransactionalEmail({
     transactionalId: 'tx_welcome',
     email: 'a@b.com',
     dataVariables: { firstName: 'Alex' },
   });
   
   // after
   import { Sndr } from '@rkiza/sndr';
   const sndr = new Sndr(process.env.SNDR_API_KEY!);
   await sndr.emails.send({
     from: 'hello@yourdomain.com',
     to: 'a@b.com',
     subject: 'Welcome',
     template_id: 'tx_welcome',
     variables: { firstName: 'Alex' },
   });

3. 3

   Migrate templates

   Loops templates use {{variableName}} placeholders. SNDR templates use the same {{ variable }} syntax. Most templates port over verbatim.

4. 4

   Migrate webhook handlers

   Verify with the shipped helper; switch on the typed event union.

   import { verifyWebhookSignature } from '@rkiza/sndr';
   
   app.post('/webhooks/sndr', express.raw({ type: 'application/json' }), (req, res) => {
     if (!verifyWebhookSignature(req.body, req.header('x-sndr-signature') ?? '', process.env.SNDR_WEBHOOK_SECRET!)) {
       return res.status(400).send('bad signature');
     }
     res.status(200).send('ok');
   });

5. 5

   Reuse your DNS, add SNDR DKIM

   Keep both providers in SPF during cutover. Add a fresh DKIM record under a new SNDR selector — Loops’ key stays in DNS unchanged.