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Connect Resend platform to Fondoo

Live4 min readUpdated

This connection lets Fondoo and your AI agent look inside your Resend account. The agent can list your sending domains and their verification status, and look up a single email you sent to see what happened to it. It does not send email. To send email through Resend, see the Resend email delivery guide (resend).

What Fondoo can do with it

The connector id is resend_platform. It has two capabilities, and both are read-only:

  • domains.list (read): lists the domains in your Resend account, with each domain's status (for example, whether it is verified) and region. It calls GET https://api.resend.com/domains. It takes no input.
  • email.get (read): fetches one email by its Resend email id. It calls GET https://api.resend.com/emails/{id}. The result includes the recipients, subject, the HTML and text body, and the last delivery event (such as delivered or bounced).

There is no write, delete or send action, so nothing here needs owner approval. Agents without the owner scope need the email:read scope to run these actions.

Sending is deliberately kept out of this connector. Fondoo sends email through its own send_email pipeline so that consent, suppressions, billing and approval rules always apply.

Before you start

  • A Resend account. Resend has a free plan; see Resend pricing. Reading domains and emails through the API does not cost extra.
  • Permission to create API keys in your Resend team.
  • Your Fondoo site id, if you want the connection tied to one site.

Step by step: get your credentials

Resend keys come in two permission levels: Full access and Sending access. This connector needs Full access. A Sending access key can only send email, and Resend rejects other calls from it with the error restricted_api_key. See Resend errors and Create API key.

  1. Sign in to Resend and open the API Keys page of the dashboard (guide).
  2. Click Create API Key.
  3. Give it a name you will recognise, for example Fondoo reads.
  4. Set the permission to Full access. (The domain restriction option only applies to Sending access keys, so it does not apply here.)
  5. Create the key and copy it straight away. It starts with re_. Resend shows it only once.
  6. In Fondoo, paste it into the apiKey field (see the next section). That is the only field.

Full access means the key could also create or delete things in Resend if someone else got hold of it. Fondoo only ever calls the two read endpoints above, but treat the key like a password and keep it out of chat.

Connect it in Fondoo

In the dashboard

  1. Go to Connections in the sidebar and click Connect a tool.
  2. In Find a tool, type Resend. The card for this connector is titled Resend platform.
  3. Click Use a key. When the notice "Enter your key securely" appears, click Open secure key entry.
  4. On the "Connect resend_platform" page, paste your key into apiKey and click Save connection securely. The page works once and expires after 15 minutes.
  5. The connection now shows under Connected with a masked key. Click Check connection.

By asking your agent

Example prompt: "Connect my Resend account for reading domains. Send me a secure link for the key."

The agent calls:

add_connection_key({ provider: "resend_platform", siteId: "YOUR-SITE-ID" })

It returns a one-use securePasteUrl that lasts 15 minutes. Open it and paste the key there. The agent can pass the key directly in fields, but Fondoo then warns that the key may remain in chat logs, so use the link. connect_service({ provider: "resend_platform", siteId }) returns the same setup steps with a signed link but never accepts a key.

REST equivalent:

curl -X POST https://api.getfondoo.com/v1/ops/add_connection_key \
  -H "Authorization: Bearer $FONDOO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"provider":"resend_platform","siteId":"YOUR-SITE-ID"}'

Test that it works

  1. Click Check connection, or ask the agent to run test_connection({ connectionId }). Fondoo calls GET /domains once. A pass shows status connected with the message "Cheap read succeeded; untested permissions remain unknown, not granted." Both capabilities are listed as unknown; that is normal for this connector.
  2. Ask the agent: "List my Resend domains." It runs connector_action({ connectionId, action: "domains.list", input: {} }). You should see your domains and their status.
  3. Optional: take the id of an email you sent (Resend returns it when the email is sent, and shows it in the dashboard's email logs) and ask the agent to run connector_action({ connectionId, action: "email.get", input: { id: "EMAIL-ID" } }).

Troubleshooting

  • "Connection test failed; check credentials and provider permissions." The key is wrong, deleted or a Sending access key. Create a Full access key and use Rotate (below) to replace it.
  • restricted_api_key from Resend. The key is Sending access. Change its permission to Full access in Resend, or create a new Full access key.
  • "Provider request failed (404)" when reading an email. The id must be the Resend email id (as returned when the email was sent), not the Message-ID header or a Fondoo delivery id.
  • "Connector rate budget exhausted" or a rate limit error. Wait a minute and try again. See the limits below.
  • "Credential fields do not match the connector manifest." Only apiKey is accepted. Remove any other field.
  • Domains look unverified. That is Resend's real status. Fix DNS records in Resend; this connector cannot change domains.

Limits, data and security

  • Resend limit: by default 10 requests per second per team, shared across all your keys. Going over returns HTTP 429. See Resend API introduction.
  • Fondoo limit: a conservative local budget of 60 requests per minute per connection. Resend's limits and Retry-After stay authoritative.
  • What Fondoo stores: the key, encrypted in Fondoo's connector vault. list_connections only shows a masked value. Results of email.get include message bodies, so only run it when you need the details.
  • Rotate: run rotate_connection_key({ connectionId }). It returns a new secure paste link and replaces the stored key. You can set expiresAt or rotateAfter on add_connection_key to get reminders.
  • Disconnect: run delete_connection({ connectionId }). Agents need owner approval. This removes the key from Fondoo but does not revoke it at Resend, so also delete the key on the Resend API Keys page.