SendGrid (Twilio): classic market leader for transactional and marketing email

What is SendGrid?

SendGrid is the oldest productive mail-sending API on the market -- founded in Boulder, Colorado in 2009, acquired by Twilio in 2019. Currently listed as "Twilio SendGrid", with full integration into the Twilio stack (SMS, Voice, WhatsApp Business, Verify). Unlike Postmark, which only serves transactional mail, or Brevo, which combines both, SendGrid offers two deliberately separated products under one account: "Email API" for transactional mail and "Marketing Campaigns" for newsletters, each with own sending infrastructure.

Market share is historically the largest: over 80,000 paying customers, Twilio reports about 100 billion mails sent per year through the platform in Q1 2026 earnings. This drives two effects: first, a very mature API; second, shared IP pools permanently under pressure because many weak senders sit on them. Inbox rate sits at 92-94 percent in independent tests -- good, but 5 points behind Postmark.

As of May 2026, SendGrid hosts primarily in the USA (Denver data center, AWS us-east-1) and offers an EU region ("EU SubProcessor Network", Frankfurt cluster) for GDPR-sensitive customers on Pro plans and above. The free tier was expanded in April 2024 from 100/day to 100 mails/day (previously 100/day global), but in early 2026 it became coupled to credit-card verification -- many hobbyists complain about it.

Pricing (May 2026): Free 100 mails/day, Essentials USD 19.95/month for 50,000 mails, Pro USD 89.95/month for 100k mails plus dedicated IP, Premier individual from 1M mails. Marketing Campaigns separate: Basic from USD 15/month for 5,000 contacts, Advanced from USD 60/month with automation.

Why it matters for Swiss SMEs

SendGrid is interesting for Swiss SMEs in three cases: existing Twilio stack, broad ecosystem integration, and marketing-plus-transactional combination.

Twilio stack: Whoever already uses Twilio for SMS notifications (2FA codes, dunning reminders) or Twilio Voice for phone confirmations has SendGrid "one checkbox away". API keys managed under one account, billing consolidation saves accounting work. Twilio Verify uses SendGrid internally for mail OTP -- the platform is in the stack anyway.

Salesforce/HubSpot integration: SendGrid is listed as default provider by Salesforce Marketing Cloud, HubSpot Sales Hub, Pipedrive and Zoho CRM. Whoever runs a CRM with a SendGrid connector can run transactional mail (e.g. lead confirmation, quote dispatch) through SendGrid -- without own code, just via CRM setup.

Marketing plus transactional: Unlike Postmark, which forbids marketing, or SES, which has no marketing tooling, SendGrid combines both cleanly. A fiduciary client receives quarterly reminders (transactional) and a monthly industry newsletter (marketing) via the same platform with separated IP pools -- clean reputation separation.

EU region on Pro plan and above: mails and logs in Frankfurt. DPA under GDPR in the dashboard. For revFADP compliance: data stays in EU, a TIA is presentable with standard clauses. Twilio (parent group) is based in San Francisco -- but the sub-processor contract sits in EU.

The trade-off: SendGrid is 5 points behind Postmark on deliverability. The free tier was sharply cut in 2026 (credit-card verification). The UI is 2-3 generations old and feels 2016-vintage. Whoever wants modern API DX: Resend or Postmark.

How it works

SendGrid exposes SMTP relay, REST API and SDKs (Node.js, Python, PHP, Ruby, Java, Go, C#).

SMTP relay: Host `smtp.sendgrid.net`, port 587 STARTTLS or 465 SMTPS, user `apikey`, pass the API key string. The user name is constant "apikey" -- a detail often overlooked.

REST API: Endpoint `https://api.sendgrid.com/v3/mail/send`, header `Authorization: Bearer <API-Key>`. cURL example:

``` curl -X POST "https://api.sendgrid.com/v3/mail/send" \ -H "Authorization: Bearer ${SENDGRID_API_KEY}" \ -H "Content-Type: application/json" \ -d '{ "personalizations": [{ "to": [{ "email": "[email protected]" }], "subject": "Dunning No. 2 - Invoice 2026-104" }], "from": { "email": "invoice@firm-müller.ch" }, "content": [{ "type": "text/plain", "value": "Dear Mrs Berger, ..." }] }' ```

The REST API allows batched per-recipient personalisation via the `personalizations` array -- up to 1000 recipients per request with individual substitutions.

DNS setup: SendGrid requires three CNAME records per sender domain for DKIM and link branding (click tracking via own subdomain). SPF: `v=spf1 include:sendgrid.net ~all`. DMARC: to be set by the domain owner. The Domain Authentication Wizard in the dashboard guides setup.

Webhooks (Event Webhook): In the dashboard under "Settings > Mail Settings > Event Webhook", enter the endpoint. SendGrid POSTs on delivered, bounced, dropped, deferred, processed, click, open, spamreport, unsubscribe. HMAC-SHA256 signature in header `X-Twilio-Email-Event-Webhook-Signature` -- verification recommended.

Marketing Campaigns: Fully separate module with list management, segments, drag-and-drop designer and A/B tests. Own API endpoints under `/v3/marketing/...`. Not to be confused with the transactional API path.

Test and monitoring: SendGrid offers a sandbox mode (mail processed but not delivered, for smoke tests). Dashboard yields aggregate statistics (delivered, bounced, opened, clicked) per day, plus 30-day search per recipient ("Email Activity"). Whoever needs more: export Event Webhook to Loki/BigQuery.

SendGrid setup in 5 steps

1. 01Create a SendGrid account via credit-card verification, choose plan (Free, Essentials, Pro) -- EU region from Pro upward.
2. 02Generate an API key with send permission in the dashboard, store in .env (SENDGRID_API_KEY).
3. 03Run the Domain Authentication Wizard: set three CNAME records (DKIM selectors plus link branding) in Cloudflare as DNS-only.
4. 04DMARC manually to p=none for 14 days, then raise to quarantine. Set Event Webhook to own endpoint, verify HMAC signature.
5. 05Sandbox test via `mail_settings.sandbox_mode.enable=true`, then production: three test mails to Gmail/Outlook/Bluewin and verify Mail-Tester.com 10/10.

When SendGrid fits

SendGrid is the right choice when (a) the stack already uses Twilio (SMS, Voice, Verify), (b) a CRM with SendGrid connector is central (Salesforce, HubSpot, Pipedrive, Zoho), or (c) transactional plus marketing under one vendor is desired and the "SendGrid" brand is internally known.

Concrete cases: A Swiss SaaS platform with Twilio SMS 2FA also sends mail OTP -- SendGrid saves the second vendor account. A fiduciary firm with Salesforce Sales Cloud uses the built-in SendGrid connector for quote dispatch. An SME with marketing newsletter (5,000 recipients) and transactional mail (10k/month) needs both without switching tooling.

For DACH setups: request EU region (Pro plan and above), check the sub-processor contract, set DKIM and link branding cleanly. Free tier with credit-card verification is standard in 2026 -- no CC, no account.

When not to use

SendGrid is the wrong choice when (a) maximum deliverability is required (Postmark beats SendGrid by 5-7 percent), (b) modern DX with a TypeScript-first API is expected (Resend is clearly better here), or (c) pure Swiss hosting is required (Infomaniak or AWS SES eu-central-2 are better picks).

More pitfalls: SMTP user name is "apikey" -- constant overlooked, trying the API key string as user. Expecting free tier without credit-card verification -- not possible since 2026. Using click tracking via link-branding domain without setting the DNS records -- links then point to `*.sendgrid.net` and look phishing-like. Pushing marketing and transactional mail over the same stream -- IP-pool reputation suffers, keep both separate. SendGrid account suspension on spam complaints: Twilio reacts strictly since 2024, restoration costs weeks.

Trade-offs

FAQ

Related topics

Sources

1. Twilio SendGrid Pricing 2026 · 2026-05
2. SendGrid Event Webhook Reference · 2026-04
3. SendGrid Domain Authentication Guide · 2026-03
4. EmailToolTester -- Best Transactional Email Services Q1 2026 · 2026-04