Migrate from Resend

Hiveku has a Resend-compatible API at https://app.hiveku.com/api/v1/email/resend. An app built on Resend’s SDK or REST API moves to Hiveku by changing its API key and base URL. The requests and answers are Resend’s, and every email runs the same checks as Hiveku’s own REST API.

Before you switch

Verify your domain in Hiveku

Add the domain you send from and publish its records. Keep Resend’s DNS records until the switch is done: Hiveku’s records sit beside them. See Moving from another provider.

Create a key

Create a Production key in Settings > API Keys. Add Read Emails only if your app calls emails.get. See API keys.

Recreate your webhooks

Add your endpoint as a Hiveku webhook. The event names match Resend’s, Hiveku sends the same signature headers, and an event’s data carries the same email_id, from, to, subject and tags. Give your handler Hiveku’s signing secret, and check any other field it reads.

Bring over your suppressions

Hiveku suppresses an address on its own after a hard bounce or a spam complaint, but it does not know who bounced, complained or unsubscribed at Resend. Add those addresses before you switch. See Suppressions.

Switch

Set two environment variables:

RESEND_API_KEY=hk_live_...
RESEND_BASE_URL=https://app.hiveku.com/api/v1/email/resend

Your code does not change:

import { Resend } from "resend";

const resend = new Resend(process.env.RESEND_API_KEY);

const { data, error } = await resend.emails.send({
  from: "Acme <noreply@mail.acme.com>",
  to: ["customer@example.com"],
  subject: "Your order shipped",
  html: "<p>On the way.</p>",
});

The Resend SDK reads RESEND_BASE_URL once, when it is first imported. Set it in the environment the app starts with, not in code after the import. Hiveku tests this with the resend package, version 6.

If you call Resend’s REST API yourself, send the same requests to the Hiveku base URL:

curl -X POST https://app.hiveku.com/api/v1/email/resend/emails \
  -H "Authorization: Bearer $RESEND_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "Acme <noreply@mail.acme.com>",
    "to": ["customer@example.com"],
    "subject": "Your order shipped",
    "html": "<p>On the way.</p>"
  }'

Try it with a test key (hk_test_...) first. The answer adds a warning that nothing was delivered:

{
  "id": "5f0c7a2e-8d1b-4c3e-9a4f-2b6d8e1f0a37",
  "warnings": ["Email simulated, nothing delivered: this is a test key, and only production keys send real email."]
}

What works

Resend call	Endpoint	Notes
`emails.send`	`POST /emails`	Answers `{ "id": "..." }`.
`batch.send`	`POST /emails/batch`	Up to 100 emails, without attachments. With `strict` validation, the default, one email that cannot go refuses the whole batch, and the answer names it. With `permissive`, the others go, and `errors` lists the refused ones by `index`.
`emails.get`	`GET /emails/{id}`	Needs Read Emails. A key reads only the emails it sent. A test key’s emails read back with `last_event: "delivered"`, so code that waits for delivery runs the same in testing.
`emails.cancel`, `emails.update`	`POST /emails/{id}/cancel`, `PATCH /emails/{id}`	Only for scheduled emails. Scheduled sending is not available yet, so there is nothing to cancel or move.

The fields of an email:

from, to, cc, bcc, at most 50 recipients in all
subject, html, text, and react, which the SDK turns into html before it calls Hiveku
replyTo
headers, of which only some are delivered: see Headers
tags, as Resend’s list or as an object: see Tags
attachments, with content (base64 text or a Buffer), filename, contentType and contentId, 25 MB in all
idempotency keys (idempotencyKey in the SDK, the Idempotency-Key header), kept 24 hours

A Buffer travels as JSON at about 3.6 times its size, and a request may be at most 50 MB. For a large file, send base64 instead: content: buffer.toString("base64").

What is refused

Hiveku refuses what it cannot honor, rather than sending something else:

You send	Answer
An attachment with `path`, a URL to fetch	`422 invalid_attachment`. Send the file itself in `content`.
`template`, a Resend-hosted template	`422 validation_error`. Send `html` or `text`, or a Hiveku template through send-template.
`topicId`	`422 validation_error`. Hiveku cannot check who opted out of a topic. Add those people to your suppressions, then send without it.
`scheduledAt` in the future	`400 validation_error`. Scheduled sending is not available yet.
Attachments in a batch	`400 validation_error`. Send those emails one at a time.
A list of emails, `GET /emails`	`405 method_not_allowed`. Use Settings > Email Service > Email Logs.
Domains, API keys, contacts, audiences, broadcasts and the rest	`404 not_found`. Manage domains and keys in the dashboard.

In a batch, these refuse the whole batch under strict validation. Under permissive, the refused email is listed in errors and the others go. Resend’s contacts, audiences and broadcasts have no compatible API here. Hiveku’s marketing email has its own audiences and campaigns.

Differences to know

Warnings. An answer may add warnings: what Hiveku left out, such as a header it does not deliver or a reserved tag, or what it did not deliver. The SDK hands the field back in data.
Suppressed recipients. An email whose every recipient is suppressed is not sent, but it is recorded and answered with its id and a warning. It reads back with last_event: "suppressed".
Headers. Only some headers are delivered. See Headers.
Reserved tags. Tags named channel or campaign_id, or starting with hiveku_, are dropped with a warning.
Limits. Rates and monthly emails follow your Hiveku plan. A 429 carries Retry-After. See Limits.
Old keys. A Resend key (re_...) left in place is refused with 401 invalid_api_key, and the message says to use a Hiveku key.

Errors

Errors come in Resend’s shape, { "statusCode": 422, "name": "missing_required_field", "message": "Missing required field: subject" }. Resend clients branch on name:

Status	`name`	When
`401`	`missing_api_key`	There is no `Authorization` header.
`401`	`invalid_api_key`	The key is wrong, paused or deleted, or it is a Resend key.
`403`	`invalid_access`	The key may not send.
`403`	`restricted_api_key`	A key without Read Emails called `emails.get`.
`422`	`missing_required_field`	`from`, `to`, `subject`, or both `html` and `text` are missing, or a batch is empty.
`400`, `402`, `403`, `413`, `422`	`validation_error`	Any other refusal: the domain is not verified (`403`), billing blocks sending (`402`), a field Hiveku cannot honor (`422`), and so on. `message` says which.
`400`	`invalid_idempotency_key`	The idempotency key is empty or over 256 characters.
`409`	`invalid_idempotent_request`	The key was used with a different request, or the first request’s result is unknown.
`409`	`concurrent_idempotent_requests`	The first request with this key is still being sent.
`413`, `422`	`invalid_attachment`	Attachments over 25 MB, or an attachment with `path`.
`429`	`rate_limit_exceeded`	The key’s rate.
`429`	`monthly_quota_exceeded`	The month’s emails are used up.
`429`	`daily_quota_exceeded`	The daily volume check holds API mail until 00:00 UTC.
`404`	`not_found`	No such email for this key, or an endpoint Hiveku does not serve.
`405`	`method_not_allowed`	Listing emails.
`500`	`application_error`	The email could not be sent, or something failed on Hiveku’s side. When the email provider gave no answer, the message says the email may have gone: look for it in Email Logs before sending again, because a retry with the same idempotency key answers `409`.

Suppressions

Add each address that bounced, complained or unsubscribed at Resend with POST /api/v1/email/suppressions:

curl -X POST https://app.hiveku.com/api/v1/email/suppressions \
  -H "Authorization: Bearer $HIVEKU_SUPPRESSIONS_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "email": "bounced@example.com", "reason": "Bounced at Resend" }'

It takes one address per request, answers 201, and answers 409 already_exists for an address already on the list. The key needs the email:suppressions permission. The dashboard’s key form does not offer it, but your AI assistant can create such a key.

After the switch

Watch Settings > Email Service > Email Logs, in the App sends (API and SMTP) view, as your app’s email moves over.
Test with a test key, not a trickle of real sends. Simulated sends are not counted, so they do not set a small usual day for the daily volume check. If your account already sends API mail on most days, moving a large app over in one go can pass 5 times that usual day and hold API mail until 00:00 UTC.
Once nothing sends through Resend, remove Resend’s DNS records and its include: from your SPF record.

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Before you switch

Switch

What works

What is refused

Differences to know

Errors

Suppressions

After the switch

​Before you switch

​Switch

​What works

​What is refused

​Differences to know

​Errors

​Suppressions

​After the switch

Before you switch

Switch

What works

What is refused

Differences to know

Errors

Suppressions

After the switch