AI · alternatives · 2026

24 alternatives to Open AI o3 API

Advanced reasoning models with safety-first innovation.

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. Open AI o3 API launched in 2024; newer entries below may have overtaken it.

1
OpenAI o3-mini▲510
Pushing the frontier of cost-effective reasoning
2025 · openai.com · its alternatives →
2
OpenAI o1 API ▲458
OpenAI's most advanced model, o1 API to third-party devs
2024 · developers.openai.com · its alternatives →
3
OpenAI o3 and o4-mini▲142
Advanced Visual Reasoning & Agentic Tool Use
2025 · openai.com · its alternatives →
4
OpenAI o1▲685
AI that can do general-purpose complex reasoning
2024 · openai.com · its alternatives →
5
Kimi K3▲442
Your AI assistant for deep thinking and productivity
Jul 2026 · kimi.ai · its alternatives →
6
OpenAI Open Models▲480
gpt-oss-120b and gpt-oss-20b open-weight language models
2025 · openai.com · its alternatives →
7
DeepSeek-V3.2▲198
Reasoning-first models built for agents
Dec 2025 · huggingface.co · its alternatives →
8
gpt-oss-safeguard▲119
Open safety reasoning models with custom safety policies
Oct 2025 · openai.com · its alternatives →
9
DeepSeek-V3.1▲417
The best-performing and best of value open-source AI model
2025 · chat.deepseek.com · its alternatives →
10
Evidently AIfree▲382
Open-source evaluations and observability for LLM apps
2024 · evidentlyai.com · its alternatives →
11
Theneo 3.0▲624
The API management platform for humans and agents
2024 · theneo.io · its alternatives →
12
Mistral Small 3▲446
High performance in a 24b open-source model
2025 · mistral.ai · its alternatives →
13
Qwen3-235B-A22B-Thinking-2507▲262
Qwen's most advanced reasoning model yet
2025 · huggingface.co · its alternatives →
14
Low-cost OpenAI: o3 Alternative Solution▲6
O3 alternative
2025 · sota-ai.nfshost.com · its alternatives →
15
Oxlo.ai▲378
Scale across AI models without scaling your bill
Jun 2026 · oxcode.ai · its alternatives →
16
DeepSeek-R1-0528▲218
New open-source LLM that rivals o3 in coding & reasoning
2025 · huggingface.co · its alternatives →
17
Agno▲326
Build, run, and manage agent platforms. Contribute to agno-agi/agno development by creating an account on GitHub.
2025 · github.com · its alternatives →
18
Merlin Unified API▲310
One unified API for all AI models like Gemini, GPT-4, DALL-E
2023 · getmerlin.in · its alternatives →
19
AI/ML API▲95
One API 100+ AI models
2024 · aimlapi.com · its alternatives →
20
MiMo▲116
Xiaomi's Open Source Model, Born for Reasoning
2025 · github.com · its alternatives →
21
FreeAI Playground▲18
Free access to advanced AI models: chat, compare, and create
2025 · its alternatives →
22
APIEval-20▲121
An open benchmark for AI agents that test APIs
May 2026 · resources.kusho.ai · its alternatives →
23
SwiftAI – open-source library to easily build LLM features on iOS/macOS▲74
We built SwiftAI, an open-source Swift library that lets you use Apple’s on-device LLMs when available (Apple opened access in June), and fall back to a cloud model when they aren’t available — all without duplicating code. SwiftAI gives you: - A single, model-agnostic API - An agent/tool loop - Strongly-typed structured outputs - Optional chat state Backstory: We started experimenting with Apple’s local models because they’re free (no API calls), private, and work offline. The problem: not all devices support them (older iPhones, Apple Intelligence disabled, low battery, etc.). That…
2025 · github.com · its alternatives →
24
Swift-Qwen3.8-27B, -58.3% thinking, x1.95 speed, accuracy of xhigh▲32
We’re on a journey to advance and democratize artificial intelligence through open source and open science.
Sep 2026 · huggingface.co · 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 →