# SendLayer

Source: https://catalystgroup.gg/docs/email-delivery/mailer-sendlayer/
Updated: 2026-10-19 · By Duane Garner

Connect CRM-NG SMTP to SendLayer with an API key and an authorised sending domain.

This guide shows you how to send your WordPress email through SendLayer, a transactional email service built with WordPress sites in mind. It suits small and medium sites that want simple setup and good delivery without running their own mail server. SendLayer offers a free trial so you can send your first messages before you choose a plan.

 

CRM-NG SMTP connects to SendLayer with an API key. You also authorise your domain in SendLayer so that receiving servers can confirm your mail is genuine.

 

## Before you start

 
- A SendLayer account (sign up at `https://sendlayer.com/`).
- A domain you control, with access to its DNS records.
- Administrator access to your WordPress site.

 

## Step 1: Add and authorise your domain

 
1. Sign in to SendLayer
  Go to `https://app.sendlayer.com/` and sign in.
2. Add your domain
  When you first sign in, SendLayer asks for your sending domain. If you skipped that, open the domains page from **Settings** (look for **Domains** or **Add domain**). Enter the domain you send from, for example `yourdomain.com`.
3. Copy the DNS records
  SendLayer lists a handful of DNS records, usually CNAME and TXT records for DKIM, the return path and SPF.
4. Add the records at your DNS provider
  Create each record exactly as shown. Some DNS providers add your domain to the end of the name automatically; if yours does, enter only the part before your domain.
5. Verify
  Back in SendLayer, press the verify button. Records can take from a few minutes to a day to appear. The domain must show as authorised before SendLayer will send for it.

 

Need help with DNS? See [Adding DNS records](https://catalystgroup.gg/docs/email-delivery/dns-records/).

 

## Step 2: Create an API key

 
1. Open the API keys page
  In SendLayer, open **Settings → API Keys** (the direct address is `https://app.sendlayer.com/settings/api/`).
2. Copy a key
  SendLayer creates a default key for you. Copy it, or create a new one named for this site so you can revoke it on its own later.

 

## Step 3: Connect in CRM-NG SMTP

 
1. Choose the mailer
  In WordPress, open **CRM-NG SMTP → Settings → General** and set **Mailer** to **SendLayer**.
2. Show the key field
  If you do not see the **API Key** field yet, click **Connect manually with API Key**. CRM-NG SMTP connects to SendLayer with your own API key.
3. Paste the key
  Paste your key into **API Key**.
4. Set the sender
  Set **From Email** to an address on the domain you authorised, for example `hello@yourdomain.com`, and set **From Name**. Tick **Force From Email** so other plugins cannot send from a different domain.
5. Save
  Press **Save Settings**.

 

To remove the key later, use **Remove API Key** next to the field.

 

## Send a test email

 

Open **CRM-NG SMTP → Tools → Email Test**, enter your address in **Send To**, and press **Send Email**. After the send, the test page checks your domain's SPF and DMARC records. For SendLayer it looks for `sendlayer.net` in your SPF record. See [Sending a test email](https://catalystgroup.gg/docs/email-delivery/send-a-test-email/).

 

You can also follow the message in SendLayer's activity or logs page, which shows whether it was delivered, opened, or bounced.

 

## Troubleshooting

 
- SendLayer has not finished checking your account: [Account not verified](https://catalystgroup.gg/docs/email-delivery/error-sendlayer-account-not-verified/)
- The From Email uses a domain that is not authorised yet: [Domain is not activated](https://catalystgroup.gg/docs/email-delivery/error-sendlayer-domain-not-activated/)
- The recipient bounced or complained before and is blocked: [Email address in suppression list](https://catalystgroup.gg/docs/email-delivery/error-email-in-suppression-list/)
- The key is wrong or was deleted: [Invalid API key](https://catalystgroup.gg/docs/email-delivery/error-invalid-api-key/) and [401 Unauthorized or Forbidden](https://catalystgroup.gg/docs/email-delivery/error-401-unauthorized-or-forbidden/)
- Your plan's limit is used up: [Email sending limit reached](https://catalystgroup.gg/docs/email-delivery/error-email-sending-limit/)
- Mail arrives in spam: [Emails landing in spam](https://catalystgroup.gg/docs/email-delivery/emails-landing-in-spam/)

 

## Related

 
- [Choosing a mail service](https://catalystgroup.gg/docs/email-delivery/choose-a-mailer/)
- [Adding DNS records: SPF, DKIM and DMARC](https://catalystgroup.gg/docs/email-delivery/dns-records/)
- [Verifying your DNS records](https://catalystgroup.gg/docs/email-delivery/verify-dns-records/)
- [Sender name, address and the Force settings](https://catalystgroup.gg/docs/email-delivery/sender-name-and-address/)
- [Securing settings with wp-config constants](https://catalystgroup.gg/docs/email-delivery/secure-settings-constants/)