| Mandrill | |
|---|---|
| Their stated threshold | Mandrill follows Mailchimp's compliance standards, and Mailchimp acts on bounce and complaint rates more readily than most platforms. |
| What happens if you cross it | Because Mandrill sits under a Mailchimp account, a compliance suspension on the marketing side can take your transactional sending with it. That coupling is the single most important thing to know about the product. |
| Where the bounce data lives | The Mandrill Outbound activity view, filterable by status, with the full SMTP response per message. Webhooks deliver the same events to your own endpoint. |
| How bounces are classified | Mandrill records hard bounces, soft bounces, rejections and spam complaints as distinct statuses, and maintains a rejection blacklist your application can query through the API. |
Bringing the rate down
Each step is an action inside Mandrill, in the order worth taking them.
Understand the coupling with your Mailchimp account
Mandrill requires a paid Mailchimp plan and shares compliance oversight. A marketing suspension is a transactional outage, which is a risk worth naming to whoever owns the account.
Read the rejection blacklist through the API
It holds addresses Mandrill will not send to and why. Querying it before a send stops attempts that would fail anyway.
Use webhooks rather than the activity view
Your application needs to know about a hard bounce within seconds so it can flag the user record. A dashboard is for investigating, not for reacting.
Separate transactional sending from marketing where the risk matters
If a transactional outage would be serious, a provider that does not share an account with your marketing tool removes that failure mode entirely.
Validate at registration
Transactional bounces mean your database holds addresses that do not exist, and that is fixed in the signup flow rather than anywhere in Mandrill.
The mistake people make here
A bounce report mixes two causes that need opposite responses: addresses that do not exist, and receivers refusing mail they could have delivered. The first is fixed by checking the list. The second is a sending problem and no amount of cleaning will move it.
Questions people ask
Does a Mailchimp suspension affect Mandrill?
It can. Mandrill requires a paid Mailchimp account and the two share compliance oversight, so a marketing suspension can stop transactional sending as well.
What is the Mandrill rejection blacklist?
A list of addresses Mandrill will not send to, with the reason. It is queryable through the API, which lets your application check before attempting a send.
How should my application handle a hard bounce?
Flag the address on the user record through a webhook, so the next password reset does not repeat the same failure.