Range Header Parser
Use this Range Header Parser Online to validate HTTP byte ranges, detect overlaps, and analyze coverage against total content length for efficient partial requests.
Related Utilities
Why Your HTTP Range Header Parser Online Results Matter
When you're building systems that handle partial file transfers—like video streaming buffers or document resume logic—getting your headers right is non-negotiable. An incorrect Range header often leads to a 416 Range Not Satisfiable error or, worse, silent data corruption due to overlapping segments. Our Range Header Parser Online tool acts as your first line of defense, providing a real-time visual map of exactly which bytes you are requesting and how they align with the total file size.
Understanding Byte Range Satisfiability and Coverage
The logic behind any reliable Range Header Parser Online is based on RFC 9110 specifications. A range request is defined by its unit (usually bytes) and a set of start/end coordinates. The tool evaluates these coordinates against the Content-Length to determine if your request is mathematically valid. When multiple ranges are provided in a multipart request, the tool identifies overlaps where byte indices are requested twice, and gaps where portions of the file are skipped. This visual feedback is important for developers optimizing bandwidth and server-side response caching.
Visual Overlap Detection
Instantly see where your ranges clash, preventing redundant data transfers and potential client-side parsing errors.
Gap Analysis
Identify missing byte segments in your multipart request that could cause broken file fragments.
Satisfiability Gauge
Quickly determine if your ranges fall outside the file's binary bounds before you ship the request to your production server.
Customizing Your Range Header Parser Online Parameters
To get the most accurate analysis, you need to configure the tool to mirror your specific server environment. The Range Header Parser Online relies on two primary inputs: the header string and the total file size.
| Setting | Usage | Effect |
|---|---|---|
| Range Header | The raw bytes=... string | Defines the byte segments to be parsed and validated. |
| Content Length | Total size in bytes | Sets the boundary for validity; any range exceeding this value is flagged as unsatisfiable. |
Changing the Content-Length will immediately trigger a re-calculation of the coverage map. If your Range string includes suffix-byte requests (e.g., -500), the tool automatically calculates the offset from the end of the file based on the provided length.
Evaluating HTTP Range Header Validation Logic
The Range Header Parser Online processes strings using a three-stage validation pipeline. First, it verifies the syntax—ensuring it starts with the correct unit and follows the start-end structure. Second, it calculates the absolute byte offsets. Third, it sorts these offsets to detect overlaps and gaps.
$$ \text{Valid Range} = 0 \le \text{Start} \le \text{End} < \text{Content-Length} $$
If any segment fails this inequality, the Range Header Parser Online marks the entire request as unsatisfiable. This ensures that you don't send malformed packets to your API, which could otherwise lead to unpredictable server behavior or memory leaks in your processing layer.
Input your Range String
Enter your headers like bytes=0-499, 1000-1499 into the "Range Header" field.
Set Content Length
Input the known size of your target file in bytes to enable precise boundary checking.
Observe the Coverage Map
View the color-coded bar chart where red stripes represent gaps, orange indicates overlaps, and green highlights valid segments.
Export the Command
Click the curl button to generate a ready-to-use request string for testing against your live infrastructure.
Practical Examples: Valid vs. Invalid Range Headers
To see the tool in action, consider how it interprets different formats. A standard request for the first 500 bytes is straightforward, but complex multipart requests often contain common configuration mistakes.
bytes=0-499, 500-999Two continuous valid segments (0-499, 500-999) occupying 1000 bytes of content.In contrast, an invalid request like bytes=0-499, 600-500 will trigger an immediate warning. The Range Header Parser Online identifies the 600-500 block as an error because the start index is greater than the end index, which violates the underlying protocol standards.
Quick Reference: Range Header Syntax Types
Whether you are building a custom downloader or debugging a CDN cache, knowing the syntax variations is critical.
- Standard Range:
bytes=0-499(Specific start and end) - Suffix Range:
bytes=-500(Last 500 bytes of the file) - Prefix Range:
bytes=1000-(All bytes from 1000 to the end) - Multipart:
bytes=0-99, 200-299(Multiple non-contiguous segments)
Generating Equivalent CLI Requests
For engineers who prefer testing in the terminal, the Range Header Parser Online provides a curl equivalent for every parsed input. This is particularly useful for verifying server behavior when you suspect an edge case in how your backend handles partial content. By copying the command, you ensure the exact header string parsed by the tool is sent to your endpoint, eliminating manual copy-paste errors.
Resolving Common Issues with Range Header Parser Online
Why does my multipart request show gaps in the coverage map?
When should I choose a suffix range over a standard range?
What happens if my Range header is larger than the file?
How can I verify that my server returns the correct partial content?
curl command to check if the server returns a 206 Partial Content status code.
Can this tool parse non-byte units?
bytes, which is the standard unit for HTTP partial content delivery as defined in current web specifications.