Create an API key

Create your key

Open API keys in your dashboard and choose Create API key. Any team member can create, edit, and remove keys. Fill in three fields:

• Name: up to 50 characters.
• Permission: Full access can create, delete, get, and update any resource. Sending access can only send emails. Full access is selected by default.
• Domain: only a sending-access key can be restricted to a single domain. It is All domains otherwise.

The domain selector searches your team’s domains on the server. Type a domain name to find entries beyond the initial options; the current selection stays visible while you search.

You can also create keys with POST /api-keys using a full-access key.

Store the token

The token starts with os_ and is shown once, in the View API Key dialog. Opensend stores only its hash and cannot show the token again; afterwards the list shows its first characters and last four. Keep it on your server, outside client bundles and source control.

OPENSEND_API_KEY=os_replace_me
OPENSEND_BASE_URL=https://api.example.com

The same token is the password for SMTP.

Try it

curl "$OPENSEND_BASE_URL/emails" \
  -H "Authorization: Bearer $OPENSEND_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"from":"Acme <hello@example.com>","to":["you@example.net"],"subject":"Hello from Opensend","html":"<p>Your first email is on its way.</p>"}'

What each permission can do

A sending key reaches POST /emails, POST /emails/batch, and SMTP. On any other endpoint it receives 401 restricted_api_key. A key restricted to a domain can only send from that domain. If that domain is removed, the key does not become unrestricted: it can no longer send and receives 403 restricted_api_key.

All of a team’s keys share one limit of 10 requests per second.

Edit or remove a key

Editing a key changes its name, permission, or domain without changing the token. Removing a key takes effect immediately: later requests signed with it fail, including messages on an SMTP connection that is already authenticated. Create a replacement before you remove a key that is in use.