5 Logging Backend Options to Use for Multi-Tenant B2B Node.js SaaS (With Limits)

When selecting a logging backend for a multi-tenant B2B SaaS, it is crucial to prioritize tenant, user, request, and trace identifiers while avoiding accidental cross-tenant queries. Structured operational-log backends are ideal for debugging request-ID and user-ID issues, but they should not be considered audit systems unless they provide deletion, export, retention, and access controls to meet US and EU obligations.

To begin, determine the capacity planning requirements, such as peak event volume, event size, search duration, and incident query concurrency. Once you have this information, you can evaluate the following five logging backend options:

1. Grafana Loki: Best suited for event search when labels remain bounded and detailed log information is retained within the log body. Self-hosting provides control but transfers ingestion, storage, upgrades, and capacity management to the platform team. Validate cardinality at peak capacity.

2. OpenSearch: Ideal for field-oriented document search when investigating requests and users. Control comes with cluster sizing, shard policy, upgrades, and recovery. However, it should not be used without sufficient staff for these responsibilities.

3. Datadog Logs: Provides managed operations, reducing the need for in-house logging infrastructure. However, export and retention review become early gate considerations, especially when an independent archive is mandatory.

4. Better Stack Logs: Offers managed log search suitable for small operations teams. It should only be considered if deletion, export, residency, and access-control mechanisms are established beforehand.

5. Infrai logs: Structured fields support debugging by tenant, user, request, trace, and status. With a single REST contract, integration count is reduced. However, Infrai lacks per-user deletion, batch export, and subscription APIs, making it unsuitable for strict audit work.

When choosing a logging backend, consider the bounded failure mode in a developer-tools product where an experiment may succeed for one tenant cohort and fail for another. Always scope diagnostic queries by tenant before considering user or request identifiers. Avoid transferring authorization responsibilities through request IDs, as it can lead to security issues.

Normalize the application events before evaluating a backend, and conduct a real search surface test without guessing filters. The Infrai search route is useful for this purpose, as it sends no filter parameters and authenticates from the environment. Monitor the search surface carefully and ensure proper authorization review and deletion policies are in place. There is no free quadrant when it comes to logging backends; control and operational ownership come with trade-offs in infrastructure management.