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Dev tools · alternatives · 2026

24 alternatives to VidaiMock

Open Source LLM Native Mock API Test Engine

Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes.

  1. 1
    Mockaroo▲354

    A realistic data generator to test your app

    2015 · mockaroo.com · its alternatives →

  2. 2

    Generate custom data & API to build apps in less than 30s

    2021 · retool.com · its alternatives →

  3. 3

    The low-code platform for testing AI apps

    2024 · langtail.com · its alternatives →

  4. 4

    OpenTelemetry-native observability for agents and LLMs

    Aug 2026 · openobserve.ai · its alternatives →

  5. 5
    OpenUI▲322

    Thesys just open-sourced their generative UI rendering engine. Interesting timing given where Google a2ui and Vercel's json-render are headed. The difference worth noting: a2ui and json-render both treat JSONL as the contract between the LLM and the renderer. Thesys is betting that's the wrong primitive. Their engine uses a code-like syntax (OpenUI Lang) instead — LLM writes it, renderer executes it. The argument is that LLMs are fundamentally better at generating code than generating structured data, so you get cleaner output and ~67% fewer tokens. The broader vision seems to be a…

    Mar 2026 · openui.com · its alternatives →

  6. 6
    Llama 2▲263

    The next generation of Meta's open source LLM

    2023 · developer.meta.com · its alternatives →

  7. 7

    A rapid prototyping, design collaboration and handoff tool

    2018 · its alternatives →

  8. 8MO
  9. 9AT

    I recently built a small open-source tool to benchmark different LLM API endpoints — including OpenAI, Claude, and self-hosted models (like llama.cpp). It runs a configurable number of test requests and reports two key metrics: • First-token latency (ms): How long it takes for the first token to appear • Output speed (tokens/sec): Overall output fluency Demo: https://llmapitest.com/ Code: https://github.com/qjr87/llm-api-test The goal is to provide a simple, visual, and reproducible way to evaluate performance across different LLM providers, including…

    2025 · llmapitest.com · its alternatives →

  10. 10

    Hey HN, We've been building a multi-model API for LLMs called OpenRouter since we launched the Window AI extension in April this year [0]. The events of the last week make it clear the LLM landscape is unpredictable, so LLM aggregators are picking up interest. Unlike others, we're making a router on top of a public, explorable dataset. We recently built a way to rank and visualize this data, including the token counts we see going to and from different models, both open-sourced (like Llama, Mistral, finetunes, and variants) and closed-sourced (OpenAI, Anthropic). The API supports - 50+…

    Apr 2026 · openrouter.ai · its alternatives →

  11. 11

    Create mock APIs in seconds with AI. Ship prototypes faster.

    Dec 2025 · mocknica.dev · its alternatives →

  12. 12

    Instant mock REST & LLM APIs - free, no signup required

    Feb 2026 · mockapi.dog · its alternatives →

  13. 13
    Octrafic▲130

    Test your APIs in plain English, straight from the terminal

    Mar 2026 · its alternatives →

  14. 14

    We recently added AI workflow to our drag and drop Wireframe editor. It is mainly for low fidelity wireframe generation

    2018 · wireframes.org · its alternatives →

  15. 15
    Pollux▲82

    Fake json data & json server mock API generator with JWT

    2021 · mohammedal-rowad.github.io · its alternatives →

  16. 16

    Turn TypeScript interfaces into realistic mock data

    Jun 2026 · fixture-kit.vercel.app · its alternatives →

  17. 17

    Hi HN, I built the first version of Mocktail years ago. I recently came back to the project, and after a pretty substantial rebuild, v4 is now out. Mocktail is a free and open-source, self-hosted mock API server with a built-in dashboard and database, packaged as a single ~25 MB binary. You can run it locally or on your own infrastructure — no account or hosted service required. You can define endpoints and responses, generate realistic data per request, customize headers, status codes and latency, and inspect incoming requests in real time. With v4, I also added MCP support, so coding…

    Aug 2026 · getmocktail.com · its alternatives →

  18. 18
    ezyMock▲81

    Mocking API endpoints has never been easier

    2017 · its alternatives →

  19. 19

    A library that allows you to easily mock out tests based on AWS infrastructure. - getmoto/moto

    2013 · github.com · its alternatives →

  20. 20

    Mockoon is the easiest and quickest way to run mock REST API servers. No remote deployment, no account required, free, open source and cross-platform.

    2017 · mockoon.com · its alternatives →

  21. 21

    Fake server, Consumer Driven Contracts and help with testing performance from one configuration file with zero system dependencies and no coding whatsoever - quii/mockingjay-server

    2015 · github.com · its alternatives →

  22. 22

    A developer-friendly, fast and functional HTTP(S) server.

    Nov 2025 · apimokka.github.io · its alternatives →

  23. 23

    Your LLM tests, without the provider

    2d ago · llmtest.managed-code.com · its alternatives →

  24. 24

    Henry, Matt and James here – we’re building an open source toolkit that makes it easy to integrate an LLM-powered copilot that talks to your API into software products. It works by calling API endpoints which you choose to expose to it. This lets the chatbot complete tasks within your software in response to natural language queries. It’s also open source, so you don’t have to send user data to another 3rd party. We support Llama 2, but we haven’t fine-tuned Llama 2 yet (coming soon) so highest accuracy is seen with GPT-4 or fine-tuned GPT-3.5 (much faster). We started working together 2…

    2023 · github.com · its alternatives →

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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 →