Life & fun · alternatives · 2026
24 alternatives to OpenRPC – An Interface Definition for JSON-RPC APIs
A standard, programming language-agnostic interface description for JSON-RPC 2.0 APIs
OpenRPC is an interface definition standard for JSON-RPC APIs that launched in 2019. It provides a structured format for documenting and defining JSON-RPC 2.0 APIs, making them easier to understand and implement. The… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Prices are shown for the 1 we have checked on their own sites, 1 of them free or with a free tier. OpenRPC – An Interface Definition for JSON-RPC APIs launched in 2019; newer entries below may have overtaken it.
- 1
Hey HN, we’re building an open specification that lets agents discover and invoke APIs with natural language, built on the OpenAPI standard. agents.json clearly defines the contract between LLMs and API as a standard that's open, observable, and replicable. Here’s a walkthrough of how it works: https://youtu.be/kby2Wdt2Dtk?si=59xGCDy48Zzwr7ND. There’s 2 parts to this: 1. An agents.json file describes how to link API calls together into outcome-based tools for LLMs. This file sits alongside an OpenAPI file. 2. The agents.json SDK loads agents.json files as tools for an LLM that…
2025 · github.com · its alternatives →
- 2
Lightweight web APIs for Java. Contribute to HTTP-RPC/Kilo development by creating an account on GitHub.
2015 · github.com · its alternatives →
- 3
Cortexfree▲306Turn API specs into docs, SDKs, and MCP servers
Sep 2026 · cortexdocs.dev · its alternatives →
- 4LH
WebRTC For The Curious # Introduction # WebRTC For The Curious is an open-source book created by WebRTC implementers to share their hard-earned knowledge with the world. It’s written for those who are always looking for more and don’t settle for abstraction. Key features # Focus on protocols and API
2020 · webrtcforthecurious.com · its alternatives →
- 5
Hi HN, I’m a recent CS graduate. During the past few months I wrote BinaryRPC, an open-source RPC framework in modern C++20 focused on low-latency, binary WebSocket messaging. Why I built it * Wanted first-class session support, pluggable QoS levels and a simple middleware chain (global, specific, multi handler) without extra JSON/XML parsing. * Easy developer experience A quick feature list * Binary WebSocket frames – minimal overhead * Built-in session layer (login / reconnect / heartbeat) * QoS1 / QoS2 with automatic ACK & retry * Plugin system – rooms, msgpack, etc.…
2025 · github.com · its alternatives →
- 6
2023 · openapistack.co · its alternatives →
- 7
Effortlessly discover API behaviour with a Chrome extension that automatically generates OpenAPI specifications in real time for any app or website.
2023 · github.com · its alternatives →
- 8
📄 PDF/IMG ->.MD/JSON Document OCR API for PaddleOCR and GLMOCR. Self-hostable. - majcheradam/ocrbase
Jan 2026 · github.com · its alternatives →
- 9
gRPC over WebRTC▲102gRPC over WebRTC. Contribute to jsmouret/grpc-over-webrtc development by creating an account on GitHub.
2020 · github.com · its alternatives →
- 10
Rarible Protocol▲143An open-source, cross-chain tool for NFT innovation
2021 · rarible.org · its alternatives →
- 11
Very low footprint DOM-style JSON parser written in portable ANSI C - json-parser/json-parser
2012 · github.com · its alternatives →
- 12
Hey HN, I've been using GPT a lot lately in some side projects around data generation and benchmarking. During the course of prompt tuning I ended up with a pretty complicated request: the value that I was looking for, an explanation, a criticism, etc. JSON was the most natural output format for this but results would often be broken, have wrong types, or contain missing fields. There's been some positive movement in this space, like with jsonformer (https://github.com/1rgs/jsonformer) the other day. But nothing that was plug and play with GPT. This library consolidates…
2023 · github.com · its alternatives →
- 13
Fern▲260We built the world’s first generated, idiomatic gRPC and REST SDK. If you have public gRPC and REST endpoints, Fern is the SDK provider for you.
2025 · buildwithfern.com · its alternatives →
- 14
- 15
- 16
Remote Desktop Protocol for Node.js. Contribute to citronneur/node-rdpjs development by creating an account on GitHub.
2015 · lc.cx · its alternatives →
- 17
Hey, I'm Martyn and I recently joined Zuplo. OpenAPI is a huge part of what we do, but getting a document up to scratch out of the gate, especially if you're not super well versed in the actual specification and what you should use and when. So we built a suite of tools to help with this called Rate My OpenAPI. It will score your OpenAPI document out of 100, as well as giving you individual scores in 4 key areas; completeness, SDK generation, security and documentation. Along with the score, you also get details of what the issues, or errors are, as well as guidance on what they actually…
2024 · github.com · its alternatives →
- 18
Open Model Context Protocol (omcp) — a community-driven hard fork. Build without permission. - enclawed/omcp
Sep 2026 · github.com · its alternatives →
- 19
We are pleased to launch a public preview of an open source JSON-LD database which combines the simplicity of a document db with the analytical power of semantic graph. We hope it is approachable for most any developer while having the capabilities, when needed, for data interoperability, embedded cell-level security (ReBAC style), rich shape/schema restrictions, data provenance (time travel), and fact inferencing. Why did our team at Fluree build this? Data is increasingly critical for great decision making, AI, and more. The way we typically store and manage data, mainly as an…
2023 · flur.ee · its alternatives →
- 20OS
Large Language Models (LLMs) are powerful, but they’re limited by fixed context windows and outdated knowledge. What if your AI could access live search, structured data extraction, OCR, and more—all through a standardized interface? We built the JigsawStack MCP Server, an open-source implementation of the Model Context Protocol (MCP) that lets any AI model call external tools effortlessly. Here’s what it unlocks: - Web Search & Scraping: Fetch live information and extract structured data from web pages. - OCR & Structured Data Extraction: Process images, receipts, invoices, and handwritten…
2025 · its alternatives →
- 21
HyperRPC▲3An extremely fast read-only RPC for data-intensive tasks
2024 · docs.envio.dev · its alternatives →
- 22
A generator for OpenAPI 3. Contribute to egorsmkv/openapi3-generator development by creating an account on GitHub.
2020 · github.com · its alternatives →
- 23
Author here! Agents are applying to jobs for people right now, with progressively more volume, and there's nothing built for it. So they scrape career pages and fight ATS forms with Playwright/Browser Use, which breaks constantly (or they get bot blocked). Employers get buried in applications that don't fit, candidates hear nothing back, and the resume is now an AI-written thing that another AI scores (which breaks the existing model entirely, btw). OJCP is MCP tools for search and apply, a manifest at /.well-known/ojcp.json so agents can find providers, and schemas that…
Aug 2026 · ojcp.dev · its alternatives →
- 24
Also compare
- Agents.json – OpenAPI Specification for LLMs alternatives
- WebRPC – a simple alternative to REST and SOAP alternatives
- Cortex alternatives
- Learn how WebRTC actually works. A book on the protocols, not just APIs alternatives
- BinaryRPC – Lightweight WebSocket-based RPC framework in modern C++ alternatives
- REST Alternative to GraphQL and tRPC alternatives
Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →