## Logging Library Comparison (Node.js + Python, 2 TB/day)
| Library | Type | $/mo (2 TB/day) | Retention | Node SDK | Python SDK | Query Lang | Alerting |
|-------------------|------------|-----------------|-----------------|----------|------------|--------------|--------------|
| Datadog Logs | SaaS | ~$5,400 | 15d hot, archive| 5/5 | 5/5 | Custom DSL | Yes + anomaly|
| Grafana Loki | Self-host | Infra only | Configurable | 4/5 | 4/5 | LogQL | Via Grafana |
| Axiom | SaaS | ~$1,200 | 30d hot, 1yr | 4/5 | 4/5 | APL | Yes |
| Better Stack | SaaS | ~$890 | 30d default | 5/5 | 4/5 | SQL-like | Yes |
| Elastic Cloud | SaaS/self | ~$3,600 | ILM policies | 5/5 | 5/5 | KQL / Lucene | Yes + ML |
| Signoz | Self-host | Infra only | Configurable | 4/5 | 4/5 | ClickHouse SQL| Yes |
| Coralogix | SaaS | ~$2,100 | Hot/warm/cold | 4/5 | 3/5 | Lucene / SQL | Yes + anomaly|
| ... | | | | | | | |
### Top 3 for a 50-service Node.js + Python stack:
1. Axiom — lowest cost at scale, fast APL queries, solid SDKs
2. Grafana Loki — zero license cost, pairs with existing Grafana dashboards
3. Datadog Logs — best SDK auto-instrumentation, but expensive at 2 TB/day