@flarelog/sdk

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@flarelog/sdk / FlareLogConfig

Interface: FlareLogConfig

Defined in: types.ts:61

Configuration options for the FlareLog client (v2 — OTel-native).

The biggest change from v1: apiKey is now OPTIONAL. With no API key and no OTLP endpoint configured, the SDK defaults to console output. This makes the SDK useful out-of-the-box with zero backend setup.

Properties

apiKey?

optional apiKey?: string

Defined in: types.ts:69

Flarelog API key (optional).

When provided, enables the Flarelog hosted backend transport. When omitted, the SDK still works — it just exports to console and/or any OTLP endpoint you configure via transports or env vars.

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endpoint?

optional endpoint?: string

Defined in: types.ts:72

Flarelog endpoint. Defaults to https://flarelog.dev

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allowInsecure?

optional allowInsecure?: boolean

Defined in: types.ts:75

Allow insecure HTTP endpoints (not recommended). Defaults to false

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level?

optional level?: LogLevel

Defined in: types.ts:78

Minimum log level to send. Defaults to "DEBUG"

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batchSize?

optional batchSize?: number

Defined in: types.ts:81

Number of logs to batch before sending. Defaults to 50 (Node), 1 (Worker)

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flushIntervalMs?

optional flushIntervalMs?: number

Defined in: types.ts:84

Flush interval in milliseconds. Defaults to 5000 (Node), 0 (Worker)

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debug?

optional debug?: boolean

Defined in: types.ts:87

Whether to enable debug logging (OTel diag logger + extra console output). Defaults to false

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defaultSource?

optional defaultSource?: string

Defined in: types.ts:90

Default source tag for all logs

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includeTimestamps?

optional includeTimestamps?: boolean

Defined in: types.ts:93

Whether to include timestamps automatically. Defaults to true

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autoCapture?

optional autoCapture?: AutoCaptureConfig

Defined in: types.ts:96

Automatic error capture configuration

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environment?

optional environment?: string

Defined in: types.ts:99

Environment name (e.g., "production", "staging", "development") — sets deployment.environment.name resource attr

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release?

optional release?: string

Defined in: types.ts:102

Release version — sets service.version resource attr

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serverName?

optional serverName?: string

Defined in: types.ts:105

Server hostname — sets host.name resource attr

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serviceName?

optional serviceName?: string

Defined in: types.ts:108

Service name — sets service.name resource attr. Defaults to npm_package_name or "unknown_service"

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serviceNamespace?

optional serviceNamespace?: string

Defined in: types.ts:111

Service namespace — sets service.namespace resource attr

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resourceAttributes?

optional resourceAttributes?: Record<string, string>

Defined in: types.ts:114

Extra resource attributes (in addition to OTEL_RESOURCE_ATTRIBUTES env var)

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beforeSend?

optional beforeSend?: (log) => false | LogEntry

Defined in: types.ts:117

Callback to modify or drop logs before sending. Return false to drop.

Parameters

log

LogEntry

Returns

false | LogEntry

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scrubFields?

optional scrubFields?: string[]

Defined in: types.ts:120

Fields to scrub from metadata (PII redaction). Defaults to common sensitive fields. Keys are matched by substring. SDK-instrumented attributes under the gen_ai.* and flarelog.* namespaces are exempt (token counts, latency, cost), so AI telemetry is never redacted.

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sampleRate?

optional sampleRate?: number

Defined in: types.ts:123

Sample rate for logs (0.0 to 1.0). Defaults to 1.0 (100%)

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maxBatchSize?

optional maxBatchSize?: number

Defined in: types.ts:126

Max in-flight buffer size. Defaults to 100

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onDrop?

optional onDrop?: (droppedCount) => void

Defined in: types.ts:129

Callback invoked when logs are dropped due to buffer overflow.

Parameters

droppedCount

number

Returns

void

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workerMode?

optional workerMode?: boolean

Defined in: types.ts:132

Worker mode: auto-detects if not set. When true, uses SimpleProcessor (flush on every event).

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transports?

optional transports?: TransportConfig[]

Defined in: types.ts:138

Explicit list of transports. Overrides env-var-based auto-detection. Use this when you want full control (e.g. fan-out to console + OTLP + Flarelog).

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otlpEndpoint?

optional otlpEndpoint?: string

Defined in: types.ts:145

OTLP/HTTP endpoint for any OTel backend (Grafana Cloud, Honeycomb, Tempo, etc.). Shorthand for transports: [{ type: "otlp", endpoint }]. Can also be set via OTEL_EXPORTER_OTLP_ENDPOINT env var.

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otlpHeaders?

optional otlpHeaders?: Record<string, string>

Defined in: types.ts:168

Headers for the OTLP transport (e.g. Authorization). Shorthand for transports[0].headers.

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warnOnConsoleFallback?

optional warnOnConsoleFallback?: boolean

Defined in: types.ts:107

Warn to console.warn when the SDK falls back to ConsoleTransport because no backend is configured (i.e., FLARELOG_API_KEY and OTEL_EXPORTER_OTLP_ENDPOINT are both unset AND no explicit transports array was provided).

• true (default): emit a one-time console.warn describing the fallback and how to fix it.
• false: suppress the warning (for users who intentionally want console-only logging).

The warning is emitted at most once per FlareLog instance.

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ignorePaths?

optional ignorePaths?: Array<string | RegExp | (pathname: string) => boolean>

Defined in: types.ts:202

Request path patterns to skip when wrapping handlers with workerFetch(), pagesFunction(), or logger.withRequest().

When the incoming request's URL pathname matches any entry, the SDK bypasses span creation, log emission, and end-of-request flush entirely — the handler runs as if the SDK weren't installed. This is the recommended way to keep browser-driven noise (e.g. /favicon.ico, /robots.txt, static-asset prefixes) out of your dashboard without touching your handler code.

Each entry can be:

• a string: matched if the pathname equals it (case-sensitive)
• a RegExp: matched if pattern.test(pathname) returns true
• a function: matched if (pathname) => boolean returns true

Matching happens against new URL(request.url).pathname only — query string and host are ignored.

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scrubFields?

optional scrubFields?: string[]

Defined in: types.ts:140

Fields to scrub from metadata (PII redaction). When a key in metadata matches any entry in this array (substring match), its value is replaced with "[REDACTED]" before the log is exported. SDK-instrumented attributes under the gen_ai.* and flarelog.* namespaces are exempt so AI token/latency/cost telemetry is preserved.

Defaults to common sensitive fields (e.g. password, secret, token, authorization).

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onDrop?

optional onDrop?: (droppedCount: number) => void

Defined in: types.ts:149

Callback invoked when logs are dropped due to buffer overflow (i.e. the in-flight queue exceeds maxBatchSize). Use this to track telemetry loss in your own metrics or alerting system.

const logger = flarelog({
  maxBatchSize: 100,
  onDrop: (count) => {
    console.warn(`FlareLog dropped ${count} log(s) due to buffer overflow`);
  },
});

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