Soft vs Hard Bounce Classifier
The classification rules are buried in RFC 3463 and provider-specific extensions. This tool tells you in plain English: retry, suppress, or investigate.
Suppress this address immediately. The mailbox doesn't exist.
Parses the SMTP enhanced status code (5.x.x or 4.x.x) and the freeform text. Cross-references against known patterns from Gmail, Microsoft, Yahoo, Apple, Proofpoint, Mimecast.
Building bounce processing logic. Diagnosing why a previously-deliverable address suddenly bounces. Cleaning a list after a provider migration.
FAQ
Should I suppress 4.x.x bounces?+
Not on the first occurrence. 4.x.x is transient (rate limit, temporary failure). Suppress only after 5+ consecutive 4.x.x bounces over multiple days.
What about 5.7.x codes?+
Policy rejections — usually content or reputation. Don't suppress the address; investigate your sending. Suppressing hides the symptom while the reputation problem continues.
Keep going
Articles, glossary entries, and other tools on the same topic.
You analyzed one send. Outsolvi analyzes every send, forever.
Subject scores, preview tests, header parses are one-shot. Outsolvi runs the same analysis on every email you send and surfaces patterns: which subjects open, which preheaders convert, which threads stall. From $7/user/mo yearly.
Get the continuous versionNate built Outsolvi after watching every email-tracking tool he had ever used lie to him about opens. Outsolvi runs Tier 1 to 5 confidence scoring on every open, native in Outlook and Gmail, so the number on the dashboard is one a rep can actually act on.
We update these pages when the underlying mechanics change — new mailbox-provider rules, new tracker behavior, new measurement gaps. The dates above are real revisions, not auto-touches.