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Alternatives to Discontinued OpenAI Assistants API

historical guide · 3 editor-selected alternatives · OpenAI Assistants API overview →

source: tools.alternatives · stored order · active records only; review scores are annotations and never change membership or order

A directional evidence panel appears only when the substitute rationale, trade-offs, sources, and verification date have been recorded. Older selections without that panel remain visible but are unclassified under the new evidence contract.

discontinued OpenAI deprecated the Assistants API after achieving feature parity in the Responses API. It will shut down on August 26, 2026. Existing integrations should migrate to the Responses API using OpenAI's official migration guide: https://developers.openai.com/api/docs/assistants/migration

LangChain logo
1

LangChain

82/100open sourcefreemiumexplicit relation

The most widely-used framework for building LLM-powered applications, available in Python and JavaScript. Provides abstractions for chains, agents, RAG, memory, tool usage, and structured output. Integrates with 100+ LLM providers, vector stores, document loaders, and tools. LangSmith offers tracing and evaluation. LangGraph enables stateful, multi-agent workflows with cycles. 100K+ GitHub stars. The de facto standard for LLM application development despite growing alternatives like LlamaIndex.

Freemium open-source LLM application development framework (MIT License, 100k+ GitHub stars). The core Python and TypeScript libraries (pip install langchain, @langchain/core) are 100% free ($0) with no software licensing fees. LangSmith observability offers a Developer plan ($0/mo for 1 seat with 5k traces/mo), a Plus plan at $39/seat/month with 50k traces/mo, prompt engineering playground, and automated LLM evaluations, and an Enterprise tier with custom pricing for dedicated VPC/BYOC deployments, SAML SSO, RBAC, and dedicated 99.9% SLAs.Review →
LlamaIndex logo
2

LlamaIndex

87/100open sourcefreemiumexplicit relation

Leading Python framework for building LLM-powered applications with focus on data-aware and agentic workflows. Provides tools for RAG (Retrieval-Augmented Generation), document indexing, vector store integrations, query engines, and multi-agent orchestration. 150+ data connectors for various sources. Works with OpenAI, Anthropic, local models, and more. Includes LlamaHub for community tools and LlamaCloud for managed RAG pipelines. 50K+ GitHub stars.

LlamaIndex is free and open-source under the MIT license. Managed cloud parsing and index infrastructure is offered via LlamaCloud, starting with a free tier of 10,000 credits/mo, a Starter plan at $50/mo (40,000 credits), Pro at $500/mo (400,000 credits), and tailored Enterprise plans.Review →
Vercel AI SDK logo
3

Vercel AI SDK

87/100open sourceexplicit relation

Open-source TypeScript toolkit by Vercel for building AI-powered apps with streaming chat UIs, structured outputs, tool calling, and agent workflows. Framework-agnostic core with integrations for React, Next.js, Svelte, Vue, and Nuxt. Supports a broad AI SDK v6 provider catalog including OpenAI, Anthropic, Google, xAI, Mistral, Bedrock, Groq, and OpenAI-compatible providers. Includes useChat and useCompletion hooks for rapid UI development. The standard SDK for adding AI features to web apps.

Free and 100% open source under the Apache-2.0 license developed by Vercel. Zero software licensing or seat fees. Developers only pay for their underlying LLM provider token usage (e.g., OpenAI, Anthropic, Google) or $0 when running self-hosted local models like Ollama.Review →

Open-source OpenAI Assistants API alternatives

LangChain, LlamaIndex, Vercel AI SDK — see all open-source developer tools.

Free OpenAI Assistants API alternatives

LangChain, LlamaIndex offer a free plan or free tier.

More Agent Frameworks tools

same category, not editor-selected alternatives — see how OpenAI Assistants API compares →

Grok BotGrok Bot is SpaceXAI's beta workspace for persistent AI teammates that use apps, websites, files, terminals, plugins, and MCP on a user-scoped cloud computer. Bots can learn routines, coordinate in parallel, and, when enabled by team policy, launch Cursor Cloud Agents that work on code in isolated environments and return pull requests and verification artifacts.LatitudeLatitude is an agent observability platform for teams that need to inspect LLM traces, conversations, issues, and evaluation feedback in one workflow. Its public repo and docs position it as a Sentry-style monitor for AI agents, with semantic search, issue detection, annotations, MCP-assisted fixes, and cloud or self-hosted deployment paths for production debugging.JudgevalJudgeval is the open-source post-building layer for AI agents from Judgment Labs, providing OpenTelemetry-based tracing, hosted and custom evaluation scorers, and online behavior monitoring for LLM-powered applications. Instrument any function with a single decorator, score live production traffic against faithfulness and instruction-adherence checks, and feed real-world failures back into reinforcement learning or supervised fine-tuning loops.Mem0Mem0 is an open-source intelligent memory layer for AI agents with 51K+ GitHub stars providing persistent, adaptive memory across sessions. It manages working, short-term, and long-term memory types, enabling personalized AI experiences that improve over time. Features automatic memory extraction from conversations, semantic search over stored memories, multi-format support, and integration with 100+ frameworks. Simple API for adding memory to any LLM-powered application or agent.chrome-devtools-mcpchrome-devtools-mcp is the Chrome DevTools team's official MCP server that lets coding agents control and inspect a live Chrome browser with first-party Chrome DevTools Protocol fidelity. It exposes Network inspection, Performance traces, Lighthouse audits, console output, and structured DOM snapshots as typed MCP tools, so agents can debug real pages and ship reliable web performance investigations without resorting to brittle DOM scraping.E2BE2B provides secure cloud sandboxes that let AI agents execute code, run terminal commands, and interact with filesystems in isolated environments. Each sandbox spins up in ~150ms with its own OS, giving agents a safe space to run untrusted code. Supports Python, JavaScript, and any language via custom Dockerfiles. Used by AI coding assistants, data analysis agents, and code interpreters. SDK available for Python and JavaScript with a simple API for programmatic sandbox control.OpenWikiOpenWiki is LangChain’s open-source CLI for generating and maintaining an agent-focused wiki inside a codebase. It can create an openwiki/ documentation folder, update it from repository changes, add guidance to AGENTS.md or CLAUDE.md, and run via an interactive CLI or daily GitHub Action so coding agents have durable context without stuffing every detail into prompts.SupermemorySupermemory is a memory and context platform for AI assistants and agents. It ranks #1 on LongMemEval, LoCoMo, and ConvoMem, supports MCP for Claude/Cursor-style clients, provides plugins for developer tools, and combines memory extraction, user profiles, hybrid search, connectors, and RAG in one API.CUA (Computer-Use Agent)Open-source computer-use infrastructure for agents that need to drive desktop environments in the background. CUA includes Cua Driver, Sandbox, Run, Bench, and Verified Data across Linux, Windows, macOS, and Android, with MCP and CLI surfaces for screenshots, accessibility trees, keyboard/mouse actions, shell commands, task evaluation, and fleet execution.

OpenAI Assistants API head-to-head

FAQ

Which OpenAI Assistants API alternative is listed first?

LangChain is first in the editor-selected list of 3 OpenAI Assistants API alternatives and carries an editorial review score of 82/100. The stored order is editorial; review scores do not determine membership or position.

Are there open-source OpenAI Assistants API alternatives?

Yes — LangChain, LlamaIndex, Vercel AI SDK are open source.

Are there free OpenAI Assistants API alternatives?

Yes — LangChain, LlamaIndex offer a free plan or free tier.

What should I use instead of OpenAI Assistants API?

OpenAI Assistants API has been discontinued — OpenAI deprecated the Assistants API after achieving feature parity in the Responses API. It will shut down on August 26, 2026. Existing integrations should migrate to the Responses API using OpenAI's official migration guide: https://developers.openai.com/api/docs/assistants/migration The first editor-selected replacements are LangChain, LlamaIndex, Vercel AI SDK.