Grafana Loki
Prometheus-inspired horizontally scalable log aggregation system that indexes only metadata labels, making it cost-efficient for storing and querying agent logs.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Self-hosted: auth is your responsibility. Cloud: API keys with no scopes. Multi-tenancy via X-Scope-OrgID header.
⚡ Reliability
Best When
You're already in the Grafana/Prometheus ecosystem and want low-cost log aggregation tightly integrated with metrics and traces.
Avoid When
You need powerful full-text search across log content or have teams more familiar with Elasticsearch/Kibana.
Use Cases
- • Aggregating logs from distributed agent services with label-based querying (LogQL)
- • Cost-efficient log storage compared to Elasticsearch by indexing only labels not content
- • Correlating logs with Prometheus metrics and Grafana traces in unified dashboards
- • Real-time log streaming and alerting using Loki ruler with LogQL metric queries
- • Multi-tenant log isolation for SaaS agents serving multiple customers
Not For
- • Full-text search with complex queries across log content (use Elasticsearch/OpenSearch)
- • Teams without Kubernetes or Docker infrastructure for Promtail/Alloy log shipping
- • Real-time analytics requiring SQL-like aggregations (use ClickHouse)
Interface
Authentication
Grafana Cloud Loki uses API key or username/password. Self-hosted uses configurable auth including no-auth, basic, or OAuth proxy.
Pricing
Self-hosted Loki is free (OSS). Grafana Cloud managed service has generous free tier. Enterprise licensing for advanced features.
Agent Metadata
Known Gotchas
- ⚠ High cardinality labels (user_id, request_id on every log) cause severe performance degradation — use structured log fields instead
- ⚠ LogQL query_range requires start/end in nanoseconds Unix timestamp — formatting mismatch causes silent empty results
- ⚠ Push API accepts JSON or Protobuf; timestamps must be in RFC3339 or Unix nanoseconds — milliseconds silently truncate
- ⚠ Loki does not support log updates or deletes (only via delete API with retention rules) — append-only architecture
- ⚠ Stream selectors must match exactly indexed labels — full-text search requires log line filter (|= or |~) after label match
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Grafana Loki.
Scores are editorial opinions as of 2026-03-06.