# Log Formatter

> Free multi-format log formatter for JSON, nginx, Docker, and syslog lines. Filter and inspect logs locally with zero network requests.

- **Category:** Developer
- **URL:** https://www.teafun.cyou/tools/log-formatter/
- **Privacy:** Runs entirely in your browser — no uploads, no account, no tracking.
- **Also known as:** log parser, nginx logs, syslog, docker logs
- **Related tools:** [JSON Formatter & Validator](https://www.teafun.cyou/tools/json-formatter/), [HTTP Security Headers Checker](https://www.teafun.cyou/tools/http-headers-checker/), [Structured Data Converter](https://www.teafun.cyou/tools/yaml-json-toml/)
- **Tags:** Data, Formatting, Text

## About

Paste JSON, nginx, Docker, syslog, or plain logs to normalize, filter by level, and inspect them locally in your browser.

## How to Use the Log Formatter

Paste log lines — mixed formats are fine in a single paste. The parser auto-detects per line: a leading `{` triggers JSON parsing, an `<n>` PRIVAL prefix triggers syslog RFC 5424, an IP at the start triggers Common Log Format, a level token in brackets triggers level-prefixed parsing. The summary reports total / parsed / unparsed counts and which formats were detected. Filter by severity (trace, debug, info, warn, error, fatal); the levels follow syslog ordering so picking "warn" includes warn, error, and fatal. Type in the search box to filter across timestamp, source, and message fields simultaneously. Click any row to see the raw line beside the parsed view. Copy the normalised JSON Lines output for downstream tools — `jq`, `grep`, or ingestion into Elasticsearch / Loki via filebeat.

## Why Log Normalization Matters

Production incidents involve correlating events across services that each pick their own log format. An nginx 502 in Common Log Format, a Node.js JSON log saying the upstream timed out, and a syslog message from the host kernel about an OOM kill all describe the same incident from three angles. The slow path is opening three terminals, running `tail | grep` against each, and mentally aligning timestamps. The fast path is normalising all three streams to a common schema and filtering them together. Aggregation platforms (Datadog, Grafana Loki, OpenSearch / Elasticsearch) provide this server-side, but they cost money per GB and require shipping logs out of your network. For local triage — especially on staging boxes, on customer-on-prem deployments, or when sensitive logs cannot leave the LAN — a browser-based normaliser is faster than spinning up a log stack just to ask "what failed at 14:32:07?".

_SEO title: Log Formatter – Private Browser Log Viewer | TeaFun_

## FAQ

### Which log formats are supported?

The formatter recognizes structured JSON logs, nginx access/error logs, Docker stream output, syslog-style lines, and plain level-prefixed logs. Unknown lines are still shown as plain text.

### Are logs uploaded anywhere?

No. Logs stay in the browser for parsing, filtering, and copy/export actions. Nothing leaves your device, so sensitive log entries remain private.

### Why are some lines marked as plain?

If a line does not match one of the known formats, it is kept as plain text so you can still search it and inspect it without losing any content.