iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
JSON-RPC has no built-in file value: its parameters use JSON’s type system, which does not include raw binary data. To upload a file, agree on an application-level convention: encode small, bounded files as Base64 in a JSON string, send bytes separately using multipart/form-data, or upload the file first and pass its identifier to a JSON-RPC method.
How to upload a file over JSON-RPC, when JSON has no type for a file
The key distinction is between the JSON-RPC request and the transport carrying it. JSON-RPC 2.0 defines a request format and uses JSON values for parameters; it is transport agnostic and does not define a binary or file type. The JSON-RPC 2.0 specification states that the protocol has JSON’s type system. That means an API must define how file bytes are represented or transferred.
None of the following approaches is a built-in JSON-RPC upload feature. They are design patterns that work only when the client and server agree on the request format, limits, validation, and error behavior.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Choose an upload pattern
| Pattern | Best fit | Trade-off |
|---|---|---|
| Base64 string in JSON-RPC parameters | Small, bounded files when one JSON request is convenient | Simple request shape, but the application must encode, decode, validate, and enforce limits. Large bodies can strain memory and request-size limits. |
| Multipart request with an application-defined RPC binding | An HTTP service that needs file bytes and related fields in one request | Uses a standard file-part representation, but the service must define how the parts map to the RPC request and verify middleware support. |
| Separate upload followed by JSON-RPC reference | Large files, streaming, or JSON-RPC middleware that expects application/json | Separates file transfer from the RPC call, but requires an identifier, authorization rules, and a lifecycle for the uploaded object. |
Option 1: Put Base64 in a JSON parameter
Base64 converts bytes into text that can be placed in a JSON string. RFC 4648 defines Base64 encoding; using it as a JSON-RPC file convention is an application choice, not a feature specified by JSON-RPC. It is most suitable for small, explicitly bounded files when a single request is valuable.
#1 Best Overall
- 【Latest Version USB C 3.2 Gen 2 Cable】ZeroneTeck latest USB C for Thunderbolt cable: ①This 20Gbps USB C to USB C data cable is capable of meeting your ultra-fast data transfer needs. ②USB C to USB C monitor cable support 4K@60Hz Ultra HD video output ③In addition, this Type c to Type c cable also has a faster than normal 60W data cable with 100W ultra fast charging. Makes it easy for you to solve all your problems with just one cable.
- 【20Gbps USB C Data Cable】USBC to USBC data transfer cable provides explosive transfer speed up to 20Gbps, connect hard drives and SSDs, Also suitable for phone to laptop data transfer, transfer large files in seconds and save you more work time. Meanwhile, USBC to USBC 3.2 gen 2 20gbps data transfer cable backward compatible with USB 3.1, USB 3.0 and USB 2.0.(*Note: Maximum speeds are achieved when both upstream and downstream devices are Thunderbolt 3/4 interfaces.)
- 【4K@60Hz USB C Cable for Monitor & Plug and Play】Plug and play, no drivers or applications required to use this cable! USB C monitor cord to stream 4K@60Hz (3840*2160) content directly from your phones, tablets, laptops and desktop computers to large screens such as monitors, HDTVs and projectors. You will enjoy stunning Ultra HD video and colorful image quality. (Note: Please make sure your device has a USB-C port and supports DP Alt mode).
- 【5A/100W Fast Charging Cable】USB Type C fast charging cable with E-Marker IC chip, safely charges your devices with up to 100W power. It can fully charge a MacBook Pro 60%, an iPad Pro 75%, a iPhone 15 85%, and a Switch 95% in 35 minutes. Fully satisfies the charging power needs of professionals for MacBooks Pro, Android devices, Samsung and iPad Pro. Charge any USB-C device at maximum speed for timely use and no more waiting. *Note: Requires a C-port adapter of appropriate power.
- 【Dual Vehicle System】 Flawlessly supports CarPlay & Android Auto for seamless navigation/music streaming. 20Gbps ultra-speed — 40× faster than USB 2.0 CarPlay cables with enhanced signal stability.
For example, an API might define the following parameter object. The value shown for data is illustrative; it must be replaced by the standard Base64 encoding of the file bytes.
{
"jsonrpc": "2.0",
"method": "document.import",
"params": {
"file": {
"name": "report.pdf",
"mediaType": "application/pdf",
"encoding": "base64",
"data": "<base64-encoded bytes>"
}
},
"id": 1
}Document the fields and limits so both ends handle the same representation. There is no universal file-size threshold for choosing Base64: practical limits depend on the API, intermediaries, memory use, and client and server implementations.
Rank #2
- [ Excellent Performance ] This USB C 3.1 cable connects a portable external USB C 3.1 SSD to a computer for speedy file transfer or syncs and charges Samsung smartphones or tablets equipped with the USB C port. Data synchronization is 20 times faster than USB 2.0 cables (480Mbps). (Does not support video output.)
- [ Fast Charging & High Speed Data Transfer ] This usba to usbc data power cable can sync your favourite photos, videos and music at a data transfer rate of up to 10Gbps(1250MB/s). Files can be synchronised in seconds. In addition, it can quick-charge your USB-C devices at up to 3A safe charging power. Tested charge Samsung Galaxy S22 from 0 to 60% in 30mins with Qualcomm Quick Charge 3.0 technology.Tips: USB 3.1 Gen 2 renamed to USB 3.2 Gen 2 by USB-IF in 2019.
- [ Extreme Durability & High Quality ] : Unique ABS case with the reinforced connector withstand 10000+ bending test. Durable TPE cable not only stay tangling-free but also flexible enough to be wrapped up and put in a bag ! (PS:The connector shell is wrapped around by a piece of plastic film to protect the shell from scraching ,feel free to remove the film when you use it.)
- [ Universal Compatibility ] This USB C to USB A Charger cable is Compatible with almost all USB-C devices. For Samsung Galaxy S24/S24+/S24 Ultra/S23/S23+/S23 Ultra/S22/S21/S20/S10/S9/Note 20/10/A70/A80/A90/A54, iPhone 16/16 Plus/16 Pro/16 Pro Max, iPhone 15/15 Plus/15 Pro/15 Pro Max, Google Pixel 9/8/7/6/5/, Moto G9/G8/G7/G Pure, LG G7/G6/V50, Sony XZ, Bose 700, GoPro, Nintendo switch, Samsung Galaxy Tab S6, iPad Pro 2018 11''/12.9", Samsung T7/T5, Crucial X8/X6, LaCie Rugged SSD, G-Drive, WD My Passport, Seagate Fast, SanDisk Extreme Portable SSD etc. (OnePlus phones are not supported.)
- [ What You Get ] 1 X Super-Fast USB-A to USB-C 3.1 Gen 2 Cable (3 ft including both ends), our worry-free LIFETIME WARRANTY and friendly customer service. NOTE: If you have any questions, please feel free to contact us, we will be happy to serve you and give you an easy and pleasant shopping experience.
- Specify that
datais standard Base64 and define how malformed or invalidly encoded input is rejected. - Set an explicit maximum request and decoded-file size; do not rely only on a proxy or server default.
- Define whether
nameandmediaTypeare required, and treat them as untrusted metadata.
Option 2: Send a multipart request with an RPC binding
RFC 7578 defines multipart/form-data, a representation with separate parts that can carry file bytes and related fields. It can be used outside ordinary HTML form submissions. For a file part, RFC 7578 says the data should be labeled with an appropriate media type when known, or application/octet-stream.
The standard does not define how a multipart file part binds to a JSON-RPC method or its parameters. If one request must contain both, the API owner needs to specify the request representation, part names, and how the RPC envelope is associated with each file. Confirm that the server, middleware, proxies, and clients can parse and forward that arrangement; do not assume a JSON-RPC endpoint that expects application/json will accept multipart automatically.
Rank #3
- 10Gbps Data Transfer: USB 3.1 Gen 2 cable for ultra-fast sync of 4K movies, photos, & music. It's also backward compatible with USB 3.0. DOES NOT support video output
- Universal Compatibility: Designed for iPhone 15/16/17 Series and compatible with CarPlay, Android Auto, Portable SSDs (including Samsung T7), Samsung Phone and all USB-C devices
- 3A Fast Charging & Heavy-Duty: Equipped with a 22AWG thick copper core, it handles 3A current effortlessly, ensuring stability and reliability for extended use
- Innovative Braiding: Features a sleek white nylon braiding and silver aluminum port housing, offering a stylish yet durable design
- IRMZ USB-C Data Cable Specifications: 10Gbps High-Speed Data Transfer, 3A Fast Charging, Innovative Braided Design, 3ft Length, White Color
Option 3: Upload separately, then call JSON-RPC with an identifier
A service can accept the file through a dedicated upload operation, return an opaque identifier, and then accept that identifier and any needed metadata in a JSON-RPC method. This is an architectural pattern, not a flow mandated by JSON-RPC or RFC 7578. It can keep file transfer separate from an RPC endpoint whose middleware expects JSON and is a useful option when streaming or large payloads matter.
Define what happens between the two requests: how long an unclaimed upload remains available, whether its identifier can be reused, which principal may reference it, and how the service cleans it up if the JSON-RPC call never succeeds.
Rank #4
- Move Files Fast: Transfer music, movies, or entire seasons of TV shows in seconds at 40 Gbps.
- HD Display: Connect your laptop to an external monitor to mirror or extend your screen in up to 8K@60Hz or 4K@144Hz.
- Huge Range of Power: Supports a maximum 240W charge when paired up with a compatible charger. Charge virtually any USB-C device from phones and accessories to laptops.
- Built to Last: Proven in lab tests to withstand up to 5,000 bends.
- What You Get: Anker 515 USB-C to USB-C Cable (USB4, 3.3ft), welcome guide, our worry-free 18-month warranty, and friendly customer service.
What the API contract must define
Regardless of the pattern, a working upload depends on details the standards leave to the service. Put these decisions in the API contract rather than relying on client assumptions:
Free tools Windows power users keep installed
One-click scans. No signup required.
- Representation: For Base64, define the parameter shape and encoding. For multipart, define part names and how the RPC request is supplied and matched.
- Limits: State maximum request and file sizes, including any intermediary constraints, and return a defined error when a limit is exceeded.
- Validation: Validate decoded or received content. A filename extension or declared media type alone does not establish what the file contains.
- Storage: Define whether bytes are processed immediately or stored, how long stored files remain, and what happens on partial failure.
- Authorization: Specify who can upload a file and who may use its bytes or identifier in a later RPC call.
- Errors: Document errors for malformed encoding, unsupported content, size violations, missing or expired identifiers, and authorization failures.
Secure the upload path
Treat both the bytes and accompanying metadata as untrusted input. RFC 7578 warns receivers not to use a supplied filename blindly or preserve path information as a local path. Generate server-side storage names instead of treating a client-provided filename as a safe destination.
Best Value
- Note: To get the full 10 Gbps, both ends of the cable must be plugged into USB 3.2 Gen 2 ports (USB-C and USB-A). if in doubt, check with the device's brand service or FEMORO support
- up to 10 Gbps High-Speed Data Transfer: This USB-C cable meets USB 3.2 Gen 2 spec, delivering up to 1 050 MB/s—twice the speed of USB 3.0
- up to 3A Fast Charging: This USB-A to USB-C cable carries up to 3 A. It supports both slow charging and fast charging in accordance with the USB-A standard
- 10X Tensile Strength: Double-layer cotton braided delivers 10× the tensile strength of ordinary cables and reinforced strain relief survives 20 000+ bend cycles
- Compatible with Various USB-A Devices: Including Android Auto/CarPlay; iPhone 15/16/17 series; Galaxy S08-S26 series; Galaxy A series, Google Pixel 7/8/9/10 series; Portable SSDs; MacBook Air/Pro/Neo, HP/Dell/ASUS/Surface Laptop, Mac Mini/Pro, iMac, etc.
- Enforce size limits at the application and any relevant intermediary.
- Inspect actual content using validation appropriate to the application; do not trust only the claimed media type or filename.
- Apply authorization to the upload and to any later JSON-RPC use of the uploaded object.
- Avoid logging file contents, credentials, or other secrets included in requests.
- Set cleanup and expiry rules for temporary uploads and define whether identifiers remain valid after use.
Which approach should you use?
For a small file with a strict size limit, Base64 in a documented JSON string parameter is the most straightforward single-request design. For larger files, streaming, or endpoints and middleware built around JSON-only bodies, upload separately and pass an identifier to JSON-RPC. Use multipart in one request when that requirement matters and the service can define and support an explicit mapping between the RPC request and file part.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
