Open-source and open-weight ChatGPT alternatives ranked by benchmark performance, coding strength, and deployment flexibility.
Open source ChatGPT alternative queries are a better fit for BenchLM than generic chatbot roundups because the real decision is not just interface parity. It is which self-hostable models still hold up on coding, reasoning, and research benchmarks.
BenchLM uses GPT-5.5 as the tracked OpenAI reference for ChatGPT-like performance.
Direct answer
DeepSeek V4 Pro (Max) is a strong ChatGPT alternative. It retains about 97% of GPT-5.5's general use benchmark profile. Its blended token price is about 86% lower than GPT-5.5. It is also open-weight, so you can self-host or fine-tune it.
DeepSeek · Open Weight · 1M context
DeepSeek V4 Pro (Max) is a strong ChatGPT alternative. It retains about 97% of GPT-5.5's general use benchmark profile. Its blended token price is about 86% lower than GPT-5.5. It is also open-weight, so you can self-host or fine-tune it.
BenchLM fit
94.1
Score vs ref
97%
Token cost
86% cheaper
Mistral · Open Weight · 256K context
Mistral Medium 3.5 128B is a strong ChatGPT alternative. It beats GPT-5.5 on BenchLM's general use score. Its blended token price is about 75% lower than GPT-5.5. It is also open-weight, so you can self-host or fine-tune it.
BenchLM fit
91.4
Score vs ref
~104%
Token cost
75% cheaper
Moonshot AI · Open Weight · 256K context
Kimi K2.6 is a strong ChatGPT alternative. It retains about 92% of GPT-5.5's general use benchmark profile. Its blended token price is about 86% lower than GPT-5.5. It is also open-weight, so you can self-host or fine-tune it.
BenchLM fit
87.5
Score vs ref
92%
Token cost
86% cheaper
Z.AI · Open Weight · 203K context
GLM-5.1 is a strong ChatGPT alternative. It retains about 91% of GPT-5.5's general use benchmark profile. Its blended token price is about 84% lower than GPT-5.5. It is also open-weight, so you can self-host or fine-tune it.
BenchLM fit
86.6
Score vs ref
91%
Token cost
84% cheaper
Alibaba · Open Weight · 262K context
Qwen3.6-27B is a strong ChatGPT alternative. It still posts a credible 73 score for general use work on BenchLM. Its blended token price is about 100% lower than GPT-5.5. It is also open-weight, so you can self-host or fine-tune it.
BenchLM fit
83.8
Score vs ref
80%
Token cost
100% cheaper
Z.AI · Open Weight · 200K context
GLM-4.7 is a strong ChatGPT alternative. It still posts a credible 69 score for general use work on BenchLM. Its blended token price is about 100% lower than GPT-5.5. It is also open-weight, so you can self-host or fine-tune it.
BenchLM fit
81.8
Score vs ref
~76%
Token cost
100% cheaper
BenchLM does not treat an alternative query like a generic leaderboard. This page starts from the tracked GPT-5.5 reference, then weights benchmark quality, token cost, context window, and deployment model to find realistic replacements.
That means a model can outrank the absolute leaderboard leader here if it stays close enough on benchmarks while being materially cheaper, more open, or better matched to the workflow implied by the query.
Change the goal, use case, or minimum context if this landing page is close but not exact.
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DeepSeek V4 Pro (Max) is the current top pick on this page. It scores 88 in the selected BenchLM use-case weighting and 97% of GPT-5.5's benchmark profile, with 86% cheaper as the pricing summary.
Qwen3.6-27B is the best low-cost candidate surfaced by this page. It ranks as a serious replacement while landing at 100% cheaper than the tracked GPT-5.5 reference.
Yes. DeepSeek V4 Pro (Max) is the strongest open-weight option on this page. BenchLM surfaces it because it combines self-hostable deployment with a 88 weighted score and 1M of context.
BenchLM uses GPT-5.5 as the tracked ChatGPT reference here, then scores alternatives from benchmark performance first. Token cost, context window, and open-weight preference are used to break ties and surface better real-world replacements rather than just the raw leaderboard winner.