What should I use for email logs and message search?

For email logs + message search, the best choice depends on whether you want a self-hosted system, cloud-managed search, or full email archival/compliance.

Good options

1) OpenSearch / Elasticsearch

• Best if you want powerful full-text search across email bodies, headers, and logs.
• Great for:
  • fast filtering
  • date-based queries
  • sender/recipient searches
  • troubleshooting mail flow
• Usually paired with:
  • Postfix/Exim logs
  • Mail storage indexer
  • Log shipping via Filebeat/Fluent Bit

Use this if: you need advanced search and are comfortable operating search infrastructure.

2) Graylog

• Better if your main need is centralized log management for mail server logs.
• Easier to use than raw Elastic/OpenSearch for logs.
• Good for:
  • SMTP transaction logs
  • delivery failures
  • auth logs
  • server monitoring

Use this if: you mostly want logs, alerts, and searchable operations data.

3) Mail archiving systems

Examples:

• Mailpiler
• GFI Archiver
• Microsoft Purview (Microsoft 365)
• Google Vault (Google Workspace)

These are best for:

• legal/compliance archiving
• searching actual email content
• retention policies
• eDiscovery

Use this if: you need an email archive more than a general log/search platform.

4) PostgreSQL + full-text search

• Works for smaller systems or custom apps.
• Simple to build if you’re indexing:
  • headers
  • metadata
  • message bodies
• Not as strong as Elasticsearch/OpenSearch at scale.

Use this if: the dataset is modest and you want simpler operations.

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My practical recommendation

• For logs: Graylog or OpenSearch
• For email content search: OpenSearch/Elasticsearch or a dedicated archiver like Mailpiler
• For Microsoft 365 / Google Workspace: use the built-in compliance/search tools first

If you want one “best overall” self-hosted stack

OpenSearch + Filebeat/Fluent Bit + Mailpiler

• OpenSearch for search
• Filebeat/Fluent Bit for log shipping
• Mailpiler for archiving and mailbox search

If you tell me:

1. your mail platform,
2. how many users/messages, and
3. whether this is for logs, compliance, or user search,

I can recommend a more specific setup.