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Every team can send as soon as it is created. Sendmux includes a managed Amazon SES sending account, and you can add your own accounts when you need more control. The app calls these sending accounts. The Management API calls the same resources providers.

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Default managed account

The managed account is active by default. It is best for first sends and low-volume traffic.
Managed Amazon SES is for transactional email only. Use your own provider for marketing, newsletters, or bulk promotional sends.
When usage reaches 80% of the daily limit, Request increase appears on Accounts. You can also call POST /providers/shared-amazon-ses-limit-request from the Management API. Submit the request once. Sendmux reviews it and emails the outcome.
If the managed account is inactive and no other active provider exists, sends fail with no_active_providers.

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Add your own account

Use your own provider when you need higher volume, a specific sender policy, or direct control of account credentials.
1

Open Accounts

Open Accounts and select Add Account.
2

Choose the provider type

Choose Custom SMTP, Gmail, or Outlook / Microsoft 365. HTTP API is visible as a coming-soon option.
3

Complete setup

SMTP accounts need server address, port, protocol, username, password, and optional sender defaults. Connected accounts send you through the provider’s sign-in flow.
4

Test the provider

For SMTP accounts, use Test Connection after saving. Fix any credential or network error before routing production mail through the account.

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Import accounts from a file

Use CSV to create or update custom accounts in bulk. Use a Sendmux JSON configuration file to transfer supported non-secret values without spreadsheet formatting.
1

Open the importer

Open Accounts, select Accounts, then choose Import Accounts.
2

Choose the file format

For CSV, select Download template, keep the header row unchanged, and add one account per row. For JSON, export a configuration file from the source team.
3

Review the rows

Upload the CSV or JSON file. Sendmux shows the accepted rows before it starts. CSV files also show any invalid rows, which are not imported.
4

Start the import

Select Import. You can close the tab while the import continues, then return to Accounts > Import Progress to check the result.
New accounts count towards your team’s sending account limit. Updating an existing account does not. Only one import can run for a team at a time.
JSON configuration files never contain or accept passwords or connected-account credentials. Use them to update matched accounts. To create a new SMTP account, use Add Account or a CSV with its password. Use Add Account to authorise a new Gmail or Outlook account.
The downloaded template uses these headers:
Header names are case-insensitive. The shorter SMTP headers in the template and their smtp_-prefixed alternatives are both accepted.
Sendmux checks Gmail and Outlook accounts by type and oauth_user_email, SMTP accounts by host and username, then a unique account name with the same type. Blank optional cells do not clear existing values.An import is not all-or-nothing. Review the created, updated, and failed totals, correct any failed rows, then import those rows again.

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Export or change accounts in bulk

  • Select Accounts > Export accounts as CSV for a spreadsheet-safe copy. Formula-like values are written as text, so a leading apostrophe may appear.
  • Select Accounts > Export accounts as JSON to preserve supported non-secret values exactly in a versioned configuration file. Version 1 is currently supported. Files with another version or unknown fields are rejected.
  • Passwords and connected-account credentials are never included in either export. CSV keeps its password column blank. JSON omits credential fields.
  • Search or filter by status, group, or type, then select accounts to activate, deactivate, update quotas, update tracking, or delete them.

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Monitor account health

Search by account details or filter by status, group, and type. Each row shows throughput, recent delivery health, status, and last use. Status can be active, inactive, pending, or error. When available, the error reason appears below the account name. Open an SMTP account’s menu and select Test connection before routing production mail through it.

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Get sending credentials

Select Setup to generate a sending key and copy the current SMTP and HTTP connection details.

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Manage accounts by API

Use the Management API when you need to automate account operations. Connected account setup still starts in the Sendmux app. After connection, the API can read, activate, deactivate, delete, and update safe account metadata.
The shared Amazon SES account is platform-managed. API clients can read it, activate or deactivate it, and request a daily limit increase. They cannot edit its credentials, quotas, routing weight, sender defaults, or delete it.

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Advanced settings

Advanced settings let you tune the provider without changing every send request.

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Account limits

Each team starts with 200 sending accounts that you add yourself. The managed account does not count towards this limit. When usage reaches 80%, Request increase appears on Accounts, and API clients can call POST /providers/limits/sending-accounts/request-increase.

Delivery groups

Group providers and route selected keys or mailboxes through them.

HTTP provider

See what the coming-soon provider type means.

Domains

Verify custom domains before using them for branded sending.

Deliverability

Watch bounce, complaint, and provider health signals.