Add your JSON file
Drop one or more .json files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
JSON to CBOR
Restructuring .json data as .cbor changes the serialization without touching the values themselves. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop JSON files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting JSON data to CBOR
Restructuring .json data as .cbor changes the serialization without touching the values themselves. A .json file holds JavaScript Object Notation: nested objects, arrays, strings, numbers, booleans, and null written in a strict text syntax. It is the default data language of the web — most APIs speak nothing else.
A .cbor file holds Concise Binary Object Representation data: a binary format built on the JSON data model but standardized by the IETF, with a tag mechanism that lets it carry dates, big integers, decimals and arbitrary application types without inventing a convention for each one. For this route the practical draw is an actual IETF standard with a stable, versioned specification and tags express types JSON cannot, without breaking decoders that ignore them — balanced against tag semantics are only as portable as the two ends' agreement on them, which is worth knowing before you commit a large batch.
Why convert JSON to CBOR?
The practical trigger for this conversion is usually a mismatch: with .json, no comments — a perpetual annoyance for configuration files. Switching to .cbor buys you an actual IETF standard with a stable, versioned specification, which is why it is the better fit for webAuthn and FIDO2 attestation and assertion payloads. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
JSON vs CBOR at a glance
| Aspect | JSON data (.json) | CBOR (.cbor) |
|---|---|---|
| Format type | Text-based — characters and structure, so there is no visual quality loss | Lossless — every pixel or sample is preserved exactly |
| How it stores data | exactly six value types; no dates, no comments, no trailing commas — the strictness is deliberate | every item begins with a major type in the top three bits and a length or value in the remaining five, which makes decoders small enough for microcontrollers |
| Strongest at | rEST and HTTP API request and response payloads | webAuthn and FIDO2 attestation and assertion payloads |
| Weak spot | no comments — a perpetual annoyance for configuration files | tag semantics are only as portable as the two ends' agreement on them |
Pick CBOR as the output
Select .cbor in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if CBOR is selectable, the route is real and validated.
Convert on your device
Press Convert. The restructuring is plain local parsing — your data is never posted to a server for processing.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid CBOR file. Outputs keep the original filename with the .cbor extension.
JSON to CBOR questions, answered
Will converting JSON to CBOR lose quality?
There is no visual quality to lose — json is text-oriented and cbor is lossless-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Is it private to convert JSON files here?
Yes — the .json file is processed inside your browser tab and never uploaded. The restructuring is plain local parsing — your data is never posted to a server for processing. Close the tab and the file is gone from memory.
Where will the CBOR file work?
Libraries are widely available for C, Rust, Go, Python, Java, JavaScript and .NET, and browsers speak CBOR indirectly through the WebAuthn API. Novus Convert normalizes .cbor locally into a JSON-compatible model and writes JSON, CSV, XLSX, YAML or YML. Tagged values that JSON cannot represent are converted to a documented textual form rather than being silently discarded.
Will the CBOR file be bigger or smaller than my JSON?
It depends on the content: every item begins with a major type in the top three bits and a length or value in the remaining five, which makes decoders small enough for microcontrollers. Convert one representative file first and compare before batch-processing a large set.
Can I convert CBOR back to JSON?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .json → .cbor → .json is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.