# Logfmt to JSON Structured Log Bridge Convert logfmt (key=value) to JSON or JSON back to logfmt, with quote escaping, number/boolean coercion, and duplicate-key handling. > Canonical page: https://elysiatools.com/en/tools/logfmt-to-json-structured-log-bridge - **Category:** Format Conversion - **Keywords:** logfmt, json, log, structured, heroku, loki, vector, observability, convert, sre ## Overview logfmt (key=value pairs separated by spaces) is the native format of syslog-ng, Heroku log drains, Vector, Grafana Loki, and many Go logging libraries. This tool converts it to structured JSON for ingestion into ELK/Datadog/Splunk — and back. It handles quoted values with embedded spaces and escaped quotes, coerces numeric and boolean strings to typed JSON values, and lets you choose how duplicate keys are treated (warn-last-wins, collect into an array, or strict error). ## Inputs - **Input** (textarea): level=info msg="server started" port=8080 ts="2026-07-25T10:00:00Z" - **Direction** (select) - **Coerce Numbers** (checkbox) - **Coerce Booleans** (checkbox) - **Drop Null Values** (checkbox) - **Duplicate-Key Mode** (select) - **Indent JSON (spaces)** (number) ## When to use - Convert application or service logfmt entries into structured JSON for log analysis workflows. - Turn JSON log records into compact logfmt for systems and libraries that use key=value output. - Check how duplicate keys, quoted spaces, escaped quotes, numbers, booleans, and null values are represented. ## How it works - Enter a logfmt record or JSON object in the Input field. - Choose either logfmt → JSON or JSON → logfmt. - Enable or disable number coercion, boolean coercion, and null-value removal as needed. - Choose duplicate-key behavior and set JSON indentation from 0 to 8 spaces, then read the text result. ## Use cases - Prepare logfmt records as structured JSON for ELK, Datadog, Splunk, or other JSON-based log workflows. - Convert JSON records into logfmt for Heroku-style logs, Vector pipelines, or Go logging workflows. - Normalize log fields while preserving quoted messages and choosing an explicit duplicate-key policy. ## Frequently asked questions ### What input formats does this tool support? It accepts logfmt key=value text and JSON, depending on the selected conversion direction. ### Can quoted logfmt values contain spaces? Yes. Quoted values with embedded spaces and escaped quotes are supported. ### How are numbers and booleans converted? When enabled, numeric and boolean strings are converted to typed JSON values during logfmt to JSON conversion. ### How does the tool handle duplicate keys? You can warn and use the last value, collect values into an array, or return a strict error. ### Can null values be removed? Yes. Enable Drop Null Values to omit null values from the converted output. ## Related tools - [JSON Key Extractor](https://elysiatools.com/en/tools/json-key-extractor): Extract all keys from JSON objects with multiple output formats. 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