# Migrate Sendgrid

> Use when migrating SendGrid email integration to Resend - detects @sendgrid/mail, sgMail, sendgrid-ruby, sendgrid-go, sendgrid-java, sendgrid-php, or SENDGRID_API_KEY patterns.

- Skill: `resend/migrate-sendgrid` (Agent Skill, multi-file: 5 files)
- Install (CLI): `npx skillmds@latest add resend/migrate-sendgrid`
- Raw SKILL.md: https://api.skillmd.com/api/skills/resend/migrate-sendgrid/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- License: MIT
- Author: resend (https://skillmd.com/u/resend)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/resend/migrate-sendgrid

---


# Migrate from SendGrid to Resend

## Overview

Resend is a modern email platform for developers. This skill covers migrating SendGrid integrations to Resend across all supported SDKs.

**Automated tool:** [resend.com/migrate/sendgrid](https://resend.com/migrate/sendgrid) — paste SendGrid code and get Resend code instantly.

## Detection Patterns

Code is SendGrid if it contains any of: `@sendgrid/mail`, `sendgrid`, `SendGrid`, `SENDGRID`, `sgMail`, `sg.client`, `sendgrid-ruby`, `sendgrid-go`, `sendgrid-java`, `sendgrid-php`

## Migration Checklist

- [ ] Verify domain in [Resend Domains](https://resend.com/domains) (SPF/DKIM/DMARC)
- [ ] Create API key at [resend.com/api-keys](https://resend.com/api-keys)
- [ ] Replace env var: `SENDGRID_API_KEY` → `RESEND_API_KEY`
- [ ] Replace SDK (see [SDK Examples](./references/sdk-examples.md))
- [ ] Map webhook events (see [Webhooks](./references/webhooks.md))
- [ ] Update SMTP config if used (see [SMTP](./references/smtp.md))
- [ ] Review feature differences (see [Feature Mapping](./references/feature-mapping.md))

## Key Differences at a Glance

| Aspect | SendGrid | Resend |
|--------|----------|--------|
| API endpoint | `https://api.sendgrid.com/v3/mail/send` | `https://api.resend.com/emails` |
| Auth header | `Authorization: Bearer $SENDGRID_API_KEY` | `Authorization: Bearer $RESEND_API_KEY` |
| Batch send | `sgMail.sendMultiple()` | `resend.batch.send()` |
| Response | `[response, body]` | `{ data, error }` |
| Idempotency | Not supported | `Idempotency-Key` header or SDK option |
| Rate limit info | Error only | IETF-standard response headers |
| Rust SDK | No official SDK | `resend-rs` available |
| Templates | Dynamic templates (`templateId`) | React Email components or `html` |
| Tracking | Per-email `trackingSettings` | Configured per-domain in dashboard |
| Unsubscribe groups | `asm` field | Resend Topics (`topic_id`) |
| IP pools | `ipPoolName` field | Account-level in dashboard |

## Quick Reference

| Reference | Use When |
|-----------|----------|
| [SDK Examples](./references/sdk-examples.md) | Converting code for Node.js, Python, Ruby, Go, PHP, Java, .NET, Elixir, cURL |
| [SMTP](./references/smtp.md) | Updating SMTP hostname, port, credentials |
| [Webhooks](./references/webhooks.md) | Mapping SendGrid event types to Resend event types |
| [Feature Mapping](./references/feature-mapping.md) | Templates, tracking, unsubscribe groups, idempotency |

## Dashboard Concepts

| SendGrid | Resend |
|----------|--------|
| Sender Authentication | Domains page |
| Activity | Emails page |
| Dashboard (stats) | Metrics page |
| Event Webhook | Webhooks page |

## Common Mistakes

| Mistake | Fix |
|---------|-----|
| `asm` has "no equivalent" in Resend | It does — use `topic_id` field + Resend Topics. See [Feature Mapping](./references/feature-mapping.md) |
| Webhook `unsubscribe` maps to `email.unsubscribed` | That event doesn't exist. Use `contact.updated`. See [Webhooks](./references/webhooks.md) |
| `sendAt: unixTimestamp` copied over | Resend uses ISO 8601 string: `scheduledAt: new Date(...).toISOString()` |
| Expecting `[response, body]` from `resend.emails.send()` | Resend returns `{ data, error }` |
| Looking for a CLI migration tool | The tool is a web UI: [resend.com/migrate/sendgrid](https://resend.com/migrate/sendgrid) — no CLI |
| `sgMail.sendMultiple()` replaced by passing array to `to` field | Wrong — `to` array sends one email to multiple recipients. `resend.batch.send()` sends multiple different emails in one call |
| `dropped` SendGrid event has no Resend equivalent | Monitor `email.bounced` and `email.delivery_delayed` instead. See [Webhooks](./references/webhooks.md) |
| Resend SMTP only supports ports 465 and 587 | Resend also supports 2465 (SMTPS) and 2587 (STARTTLS) as alternatives. See [SMTP](./references/smtp.md) |
| Forgot to rename env var | `SENDGRID_API_KEY` → `RESEND_API_KEY` |

## Resources

- [Full migration guide](https://resend.com/migrate/sendgrid)
- [Resend API reference](https://resend.com/docs/api-reference)
- [React Email](https://react.email) — component-based email templates
- [Resend Broadcasts](https://resend.com/broadcasts) — for marketing/newsletter campaigns