| SparkPost | |
|---|---|
| Their stated threshold | SparkPost's guidance points at bounce rates under 5% for transactional sending and lower for marketing, with account review above that. |
| What happens if you cross it | SparkPost reviews accounts with sustained poor metrics and can restrict sending. Enterprise accounts get deliverability support before it reaches that point. |
| Where the bounce data lives | The Signals analytics dashboard for trends by classification code, the Events API for message-level detail, and the suppression list for blocked addresses. |
| How bounces are classified | SparkPost assigns numeric bounce classification codes to each failure, separating invalid recipients from policy rejections, content blocks and infrastructure problems. Those codes are the most actionable thing in the product. |
Bringing the rate down
Each step is an action inside SparkPost, in the order worth taking them.
Group bounces by classification code
The codes distinguish an invalid recipient from a policy rejection and a spam block. Those are three different problems and a hard bounce label collapses them into one.
Separate list problems from reputation problems
Invalid recipient codes mean bad addresses. Policy and block codes mean your reputation with that receiver. Only the first is fixed by cleaning.
Wire the Events API or webhooks into your system
Message-level events let your application suppress an address immediately rather than discovering it in a dashboard days later.
Use Signals to watch the trend by receiving domain
A problem concentrated at one domain is a reputation conversation with that receiver, not a list clean.
Validate where addresses enter your system
There is no list to clean in an API-driven platform, so the check belongs in your signup or ingestion path.
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
What are SparkPost bounce classification codes?
Numeric codes assigned to each failure that separate invalid recipients from policy rejections, content blocks and infrastructure problems. They let you automate a different response per cause.
Which codes mean a bad address?
The invalid recipient classifications. Policy, block and spam classifications are about your sending reputation and cleaning the list will not move them.
How do I get bounces into my own system?
Webhooks or the Events API. A dashboard tells you afterwards; a webhook lets the application stop before it sends again.