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AI · alternatives · 2026

24 alternatives to Relai-SDK – simulate → evaluate → optimize AI agents

What relai-sdk is an open-source toolkit for making AI agents reliable via a complete learning loop: simulate → evaluate → optimize. Why Agent runs are stochastic; tool-calls fail; hard to reproduce, measure, and fix at scale. It’s also hard to align behavior with goals across output quality/format, cost, and latency. We need a loop that integrates user feedback and LLM evaluators directly into the agent code (prompts, configs, models, graphs) without overfitting. How - Simulation: LLM personas, mocked MCP servers/tools, synthetic data; can condition on real traces - Evaluation:…

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 3 we have checked on their own sites, 3 of them free or with a free tier.

  1. 1
    Rerun▲301

    The easiest way to build AI agents for all your tasks

    Jul 2026 · rerun.build · its alternatives →

  2. 2
    SimplAIfree tier, from $5/mo▲589

    Hey HN, I've been building SimplAI for the past several months — it's a platform for building, testing, and deploying LLM-powered agents and multi-step workflows. The problem I kept running into: spinning up an AI agent pipeline means stitching together prompt management, tool calling, memory, evals, and deployment — often from scratch every time. SimplAI tries to be the layer that handles all of that so you can focus on what your agent actually does. What it does: - Visual + code-first workflow builder for chaining LLM calls, tools, and APIs - Built-in prompt versioning and A/B testing…

    2025 · simplai.ai · its alternatives →

  3. 3

    An open benchmark for AI agents that test APIs

    May 2026 · resources.kusho.ai · its alternatives →

  4. 4

    Hi HN! We’re the team behind Fiddler, and we recently built an Agent Cache feature. It works by capturing an LLM request/response pair and, once caching is enabled, serving subsequent matching calls locally so duplicate requests never hit the provider. It’s meant to reduce three pains that show up together in agent development: token cost, feedback-loop latency, and output non-determinism. We’d love to hear your thoughts.

    Aug 2026 · telerik.com · its alternatives →

  5. 5

    Build production-ready agents, fast.

    2025 · github.com · its alternatives →

  6. 6
    DSH Desktopfree▲176

    Official app for DeepSeek’s open-source agent harness

    23d ago · deepseek.com · its alternatives →

  7. 7
    Spec27▲34

    Hi HN! We’re a team of ML validation specialists and we’ve been building /Spec27, a tool for testing whether AI agents still do their job safely and reliably as models, prompts, tools, and surrounding systems change. We started working on this because a lot of current LLM evaluation work seems aimed at scoring general model behavior, while many teams are deploying systems that have a specific mission to fulfill. Many of the tools also assume you have full access to the agent stack and traces so you can place SDKs and Gateways, but a lot of agents are being created on vendor platforms…

    Apr 2026 · spec27.ai · its alternatives →

  8. 8

    The TypeScript SDK for AI agents with self-improving memory

    Jun 2026 · eidentic.dev · its alternatives →

  9. 9
    Cognitorafree▲86

    Built a multi-agent research system with OpenAI Agents SDK where specialized AI agents collaborate autonomously: Master Orchestrator → Data Analyst → Statistician → Report Writer Each agent has specific expertise. The orchestrator delegates tasks. All agents can execute code securely to solve problems. Example workflow: "Analyze e-commerce data" - Data Analyst: writes Python to load/clean data, spots trends - Statistician: performs significance tests, calculates growth rates - Report Writer: synthesizes findings into executive summary This demonstrates OpenAI Agents SDK's handoff system…

    2025 · cognitora.dev · its alternatives →

  10. 10
    AgentSDR▲106

    Open-source AI SDR

    16d ago · agentsdr.ai · its alternatives →

  11. 11

    Hi HN, We built something new! It is an AI agent that can: - iterate through up to a dozen sources (web or GDrive) - reason between hops in natural language (exposed in the trace) - generate structured JSON so downstream code can consume results deterministically It not only delivers state-of-the-art performance on both SimpleQA and Reka Research-Eval, but also shatters the notion that cutting-edge AI must come at a premium, being significantly more affordable than alternatives. Tech stack highlights - Base model: Reka Flash 3.1 (trained from scratch, post-trained with RL on verifiable…

    Apr 2026 · reka.ai · its alternatives →

  12. 12

    Hi HN! I’m Tony, co-founder of Inngest. I wanted to share AgentKit, our Typescript multi-agent library we’ve been cooking and testing with some early users in prod for months. Although OpenAI’s Agents SDK has been launched since, we think an Agent framework should offer more deterministic and flexible routing, work with multiple model providers, embrace MCP (for rich tooling), and support the unstoppable and growing community of TypeScript AI developers by enabling a smooth transition to production use cases. This is why we are building AgentKit, and we’re really excited about it for a few…

    2025 · github.com · its alternatives →

  13. 13DA

    Write a task in plain English. An AI agent runs it on a simulator on your Mac and tells you if a real user could complete it. Save the successful run as a regression check you can replay later.

    Aug 2026 · app.deltix.ai · its alternatives →

  14. 14

    A clean, modular SDK for building AI agents with OpenHands V1. - OpenHands/software-agent-sdk

    Dec 2025 · openhands.dev · its alternatives →

  15. 15

    I'm Josh, founder of Synth. We've been working on coding agent optimization with method like GEPA and MIPRO (the latter of which, I helped to originally develop), agent evaluation via methods like RLMs, and large scale deployment for training and inference. We've also worked on patterns for memory, processing live context, and managing agent actions, combining it all in a single stack called Horizons. With the release of OpenAI's Frontier and the consumer excitement around OpenClaw, we think the timing is right to release a v0. It integrates with our sdk for evaluation and optimization but…

    Feb 2026 · github.com · its alternatives →

  16. 16

    Hi, I'm a Dapr CNCF project maintainer. We've recently released Dapr Agents which provides agentic AI features together with built-in durable execution to guarantee statefulness and reliable agentic workflows that run to completion and retry upon failure. It runs natively on Kubernetes, has built-in OTEL integration and uses a lightweight architecture where agents scale to zero, allowing you to run thousands of agents on commodity hardware. It'd be great if you can test it out and give us feedback.

    2025 · github.com · its alternatives →

  17. 17

    Hey HN! I'm excited to share Reagent, an open source Javascript framework to build UI rich AI agents using graph based workflow. Github: https://github.com/reagentai/reagent There are already amazing tools for building agents but most of them seem to be focused on building the AI workflow on the backend with markdown as final output. There is generative UI in AI SDK from vercel but it seems to work only with server components afaik. So, I created a framework for building AI agents with interactive UI components; you can render any component from LLM tool, update it's…

    2024 · github.com · its alternatives →

  18. 18

    We built meta-agent: an open-source library that automatically and continuously improves agent harnesses from production traces. Point it at an existing agent, a stream of unlabeled production traces, and a small labeled holdout set. An LLM judge scores unlabeled production traces as they stream. A proposer reads failed traces and writes one targeted harness update at a time, such as changes to prompts, hooks, tools, or subagents. The update is kept only if it improves holdout accuracy. On tau-bench v3 airline, meta-agent improved holdout accuracy from 67% to 87%. We open-sourced meta-agent.…

    Apr 2026 · github.com · its alternatives →

  19. 19

    AI agents can generate code, but still struggle to understand what they build. Reticle brings Jev-style machine-native runtime perception to web & desktop applications. - reticlehq/reticle

    2d ago · github.com · its alternatives →

  20. 20

    Hi all, I'm the creator and maintainer of Dapr. Today we announced an agentic AI framework that allows developers to run thousands of agents on a single core that can scale to/from zero with minimal latency, with a durable execution engine that supports automatic retries. Us maintainers would very much appreciate your feedback

    2025 · github.com · its alternatives →

  21. 21

    GitHub: https://github.com/ClioAI/kw-sdk Most AI agent frameworks target code. Write code, run tests, fix errors, repeat. That works because code has a natural verification signal. It works or it doesn't. This SDK treats knowledge work like an engineering problem: Task → Brief → Rubric (hidden from executor) → Work → Verify → Fail? → Retry → Pass → Submit The orchestrator coordinates subagents, web search, code execution, and file I/O. then checks its own work against criteria it can't game (the rubric is generated in a separate call and the executor never sees it…

    Feb 2026 · github.com · its alternatives →

  22. 22

    We’re excited to share ML-Dev-Bench, a new open-source benchmark that tests AI agents on real-world ML development tasks. Unlike typical coding challenges or Kaggle-style competitions, our benchmark simulates end-to-end ML workflows including: - Dataset handling and preprocessing - Debugging model and code failures - Implementing new model architectures - Fine-tuning and improving existing models With 30 diverse tasks, ML-Dev-Bench evaluates agents across critical stages of ML development. To complement this, we built Calipers, a framework that provides systematic performance evaluation and…

    2025 · github.com · its alternatives →

  23. 23

    Steve from Temporal here. Temporal is an MIT open source project for reliable execution at scale. I adapted+extended some of OpenAI's Agents SDK samples to integrate with Temporal. These demo agents can survive process crashes, scale to millions of executions in parallel and have easy-to-implement human interactivity. Just add a couple of Python decorators to your OpenAI agent code, run Temporal workers and you're ready to go. Check the video I did with OpenAI showing this in action (it's linked in the repo). OpenAI actually use us for ChatGPT Images and also their Codex code writing agent…

    2025 · github.com · its alternatives →

  24. 24

    Tool-agnostic TypeScript library for observing coding agent sessions. Built-in Cursor provider, extensible to Claude Code, Codex, and OpenCode. - vtemian/agentprobe

    Mar 2026 · 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 →