Convert SRT to JSON Online Free

Parse SRT subtitle files into structured JSON data. JSON output makes subtitle cues easy to process, search, transform, and integrate into video players, captioning pipelines, or data analysis workflows.

By ChangeThisFile Team · Last updated: March 2026

Quick Answer

ChangeThisFile converts SRT subtitle files to structured JSON in your browser using JavaScript libraries. No server upload required — processing happens entirely on your device, keeping your subtitle data completely private. Each cue's timecodes and text are parsed into a clean JSON array instantly. Free with no signup.

Free No signup required Files stay on your device Instant conversion Updated March 2026

Convert SRT to JSON

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SRT vs JSON: Format Comparison

Key differences between the two formats

Feature	SRT	JSON
Format type	Plain text with line-based syntax	Structured key-value data
Cue indexing	Sequential integer on its own line	Array index or explicit id field
Timecode format	HH:MM:SS,mmm --> HH:MM:SS,mmm	Numeric milliseconds or ISO string
Programmatic access	Requires custom text parsing	Direct property access (cue.start, cue.text)
Filtering & search	Regex or line scanning	Native array filter, map, find
Multi-line text	Blank-line delimiter between cues	Newlines stored as \n in string or as array
Interoperability	Supported by most video players natively	Universal across APIs, databases, and web apps
Human readability	Easy to read and edit by hand	Readable but more verbose than SRT

When to Convert

Common scenarios where this conversion is useful

Custom video player integration

Web-based video players built with JavaScript can consume subtitle cues directly from a JSON array, eliminating the need for a runtime SRT parser. Convert your SRT track to JSON and load cues programmatically for precise timing control.

Subtitle search and full-text indexing

Index subtitle text in Elasticsearch, Algolia, or a database by converting SRT to JSON first. Each cue becomes a document with start time, end time, and text fields, enabling timestamp-aware search across entire video libraries.

Caption editing and localization pipelines

Localization tools and translation APIs accept JSON more readily than SRT. Convert an SRT file to JSON, send the text fields to a translation API, then reconstruct the output with the same timecodes.

Data analysis of dialogue and pacing

Analyze cue duration, words per minute, or dialogue density across a film or podcast series. JSON output can be loaded directly into Python (json.load), Node.js, or a spreadsheet tool for statistical analysis.

Who Uses This Conversion

Tailored guidance for different workflows

Developers

Load subtitle cues as structured JSON into a React or Vue video player component without writing an SRT parser
Send subtitle text fields to a translation API and reassemble with the original timecodes

Validate that start and end millisecond values are non-null before using them in timing logic

Preserve the original SRT file alongside the JSON so you can regenerate if your pipeline changes

Content Creators

Export a transcript with timestamps from an SRT file for editing in a spreadsheet or document tool
Share subtitle data with a localization team using a format their translation management system accepts

Review the first few cues in the JSON output to confirm text and timecodes look correct before processing the full file

Keep a backup of the original SRT if you plan to re-upload to YouTube or a streaming platform

Data Analysts

Analyze words-per-minute pacing across episodes by computing cue duration and text length from JSON fields
Load subtitle cues into a Pandas DataFrame using json.load() for dialogue frequency or sentiment analysis

Use the numeric millisecond timecodes directly for duration calculations rather than parsing time strings

Filter out cues with very short durations (under 500ms) which are often sound effects or music notations rather than dialogue

How to Convert SRT to JSON

1

Select your SRT file

Drag and drop your SRT file onto the converter, or click browse to choose from your files.
2

Instant conversion

The browser converts your SRT to JSON locally. No upload needed and no data leaves your device.
3

Download the JSON

Save your converted JSON file. Ready to use immediately.

Frequently Asked Questions

What does the JSON output look like?

The output is a JSON array of cue objects. Each object contains an id (the cue sequence number), a start time, an end time (both in milliseconds), and a text field with the subtitle content. Timecodes are parsed from the SRT HH:MM:SS,mmm format and stored as numeric millisecond values for easy arithmetic.

Are multi-line subtitle cues preserved?

Yes. SRT cues that span multiple lines are preserved in the JSON text field with newline characters (\n) separating each line, so the visual line breaks in the original subtitle are retained.

Does it handle SRT files with HTML formatting tags?

Yes. Tags such as <b>, <i>, and <font color=...> that some SRT files include for styling are preserved as-is in the JSON text field. You can strip or keep them depending on your downstream use case.

Is my subtitle data uploaded to a server?

No. The entire conversion runs in your browser using JavaScript. Your SRT file is never sent to any server, which is important if your subtitles contain confidential or pre-release content.

Can I convert SRT files with non-English text?

Yes. The converter reads SRT files as UTF-8, so Arabic, Chinese, Japanese, Cyrillic, and other scripts are fully supported. The JSON output is also UTF-8 encoded.

What happens if a cue has malformed timecodes?

Cues with unparseable timecodes are included in the output with null for the start and end fields rather than being silently dropped, so you can identify and correct them.

Can I use the JSON output directly in a database?

Yes. Each cue object is a self-contained record with id, start, end, and text fields suitable for direct insertion into SQL or NoSQL databases. PostgreSQL's JSONB type, MongoDB, and SQLite all handle this structure natively.

How large an SRT file can I convert?

Browser-based conversion can handle SRT files with thousands of cues without issue. Performance depends on available device memory, but a typical feature film SRT file (1,000–2,000 cues) converts in well under a second.

Will the cue sequence numbers match the original SRT?

Yes. The id field in each JSON cue object corresponds to the sequence number from the SRT file. This is useful if you need to cross-reference the JSON output against the original SRT for debugging or manual review.

Can I convert the JSON back to SRT?

ChangeThisFile currently offers SRT-to-JSON conversion. To go back from JSON to SRT you would reconstruct the file in your application code, formatting each cue's millisecond timestamps back to HH:MM:SS,mmm notation.

Does the converter support WebVTT or ASS files?

This tool converts SRT specifically. WebVTT and ASS have different syntax and require separate converters. ChangeThisFile focuses on SRT as it is the most widely used plain-text subtitle format.

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Need to convert programmatically?

Use the ChangeThisFile API to convert SRT to JSON in your app. No rate limits, up to 500MB files, simple REST endpoint.

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