# Logging

Server log levels, text and JSON formats, file and socket output, slow-query logging, and OpenTelemetry log levels.

SurrealDB writes server logs to stderr by default. You can set flags on [`surreal start`](/docs/reference/cli/surrealdb-cli/commands/start.md) or the matching [environment variables](/docs/reference/cli/surrealdb-cli/environment-variables.md) and ship lines to your collector or log store.

## Core options

| Concern | CLI flag (examples) | Environment variable (examples) |
| --- | --- | --- |
| Level | `--log` | `SURREAL_LOG` |
| Format | `--log-format` (`text` or `json`) | `SURREAL_LOG_FORMAT` |
| Remote socket | `--log-socket` | `SURREAL_LOG_SOCKET` |
| File logging | `--log-file-enabled`, `--log-file-path`, `--log-file-rotation`, … | `SURREAL_LOG_FILE_ENABLED`, `SURREAL_LOG_FILE_PATH`, `SURREAL_LOG_FILE_ROTATION`, … |
| File level | `--log-file-level` | `SURREAL_LOG_FILE_LEVEL` |
| Slow queries | `--slow-log-threshold`, `--slow-log-param-allow`, `--slow-log-param-deny` | `SURREAL_SLOW_QUERY_LOG_THRESHOLD`, `SURREAL_SLOW_QUERY_LOG_PARAM_ALLOW`, `SURREAL_SLOW_QUERY_LOG_PARAM_DENY` |

Further socket and file options (`--log-socket-level`, `--log-file-name`, `--log-file-format`, and others) are documented on [`surreal start`](/docs/reference/cli/surrealdb-cli/commands/start.md) and in [Environment variables](/docs/reference/cli/surrealdb-cli/environment-variables.md).

Slow-query logging records statements that exceed your threshold. The `--slow-log-param-allow` / `--slow-log-param-deny` flags control whether bound parameters are expanded in the log line (for example turning `SELECT * FROM $table_name` into `SELECT * FROM person` when `table_name` is allowed), the use of which is recommended for any logs that may contain sensitive data.

## OpenTelemetry trace and log verbosity

OpenTelemetry trace output can be tuned separately from ordinary server logs:

* `--log-otel-level` or `SURREAL_LOG_OTEL_LEVEL` - verbosity of OTel-related tracing output.

When OTLP is enabled, **SurrealDB Enterprise** can also emit audit and slow-query records as OpenTelemetry logs when you set `SURREAL_AUDIT_OTEL_EXPORT` / `SURREAL_SLOW_QUERY_OTEL_EXPORT`. Severity mapping and dual paths (file sink versus OTLP) are summarised on [Observability (metrics and Prometheus)](/docs/manage/observability/observability.md), [Enterprise observability](/docs/manage/observability/enterprise-observability.md), and in the [Metrics reference](/docs/manage/observability/metrics.md). In-tree detail lives in [`doc/OBSERVABILITY.md`](https://github.com/surrealdb/surrealdb/blob/main/doc/OBSERVABILITY.md) on GitHub.