AI tool comparison
GLM-5.1 vs GPT-5.5
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
AI Models
GLM-5.1
#1 on SWE-Bench Pro — Zhipu's open 754B MoE beats GPT-5 on coding
50%
Panel ship
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Community
Paid
Entry
Z.ai (formerly Zhipu AI) has released GLM-5.1, a 754B-parameter Mixture-of-Experts model that's currently sitting at #1 on SWE-Bench Pro with a score of 58.4 — outperforming GPT-5.4 and Claude Opus 4.6 on long-horizon software engineering tasks. The model ships under MIT license with full weights on HuggingFace. GLM-5.1 was specifically designed for agentic software engineering workflows: multi-file reasoning, autonomous test-run-fix loops, and extended coding sessions that span hundreds of tool calls. It's not just a capability leap — at 754B active parameters via sparse MoE, it can be run more efficiently than a dense model of equivalent capability on a sufficiently provisioned cluster. The SWE-Bench Pro result is significant because that benchmark is harder to game than vanilla SWE-Bench Verified. It tests whether a model can resolve real GitHub issues with correct tests, proper diffs, and no regressions — the things that actually matter in production. For anyone running self-hosted coding agents or building on open models, GLM-5.1 just became the new baseline to beat.
AI Models
GPT-5.5
OpenAI's new flagship unifies chat, code, and browser into one agent
75%
Panel ship
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Community
Free
Entry
OpenAI shipped GPT-5.5 on April 23, 2026, positioning it as "a major step toward a unified AI super-app" that combines chat, coding, and browser use in a single model. It is accessible via a new Agent Mode dropdown inside ChatGPT for Pro, Plus, and Team subscribers, and through the API for developers. The model delivers stronger tool use and reliability than its predecessors, with particular improvements in multi-step agentic task completion. New workspace agents for ChatGPT Business and Enterprise can autonomously handle tasks across Slack, Gmail, and other connected platforms — the same territory OpenAI has been building toward since the Agents SDK launch earlier this year. GPT-5.5 is OpenAI's answer to growing pressure from Anthropic's Claude Opus 4.7, Google's Gemini Enterprise platform, and open-source contenders like Kimi K2.6 and Arcee Trinity. Whether it actually leapfrogs the competition or merely matches it is still shaking out in independent benchmarks, but for the millions of existing ChatGPT users, it's the biggest capability jump they'll feel in day-to-day use this year.
Reviewer scorecard
“If the SWE-Bench Pro numbers hold up under independent replication, this is the first open model that can genuinely replace a proprietary API for serious agentic coding work. MIT license means you can fine-tune and deploy on your own infra. This is a big deal.”
“The API reliability improvements alone make this worth upgrading. Multi-step tool use has been the weak link in production OpenAI deployments — if GPT-5.5 actually fixes flakiness in function calling chains, that's worth the token cost increase.”
“754B parameters is not something 99% of developers can run locally. You need a multi-GPU cluster or serious cloud spend. The benchmark numbers are from Z.ai's own evaluations, and Zhipu has a history of optimistic benchmarking. Wait for independent replications.”
“OpenAI's release cadence has become so fast that GPT-5.5 may already feel dated by the time you integrate it. Independent benchmark results are inconsistent — some put it behind Kimi K2.6 on coding. And the 'unified super-app' framing is marketing; you're still paying separately for every capability.”
“A Chinese lab shipping an MIT-licensed model that tops global coding benchmarks is a watershed moment for open-source AI. The geopolitical implications are real — this is the model that makes US export controls look strategically shortsighted.”
“The Slack and Gmail workspace agents are the real story — they bring agentic AI to the office worker who will never touch an API. OpenAI's distribution advantage means GPT-5.5 will be the most-used AI model on the planet within weeks of launch, regardless of benchmark rankings.”
“Unless you're building coding tools or agent infrastructure, a 754B MoE model doesn't move the needle for creative applications. The energy and infra overhead for creative use cases doesn't pencil out versus smaller, cheaper models.”
“Agent Mode in ChatGPT is finally making AI feel less like a chatbot and more like a collaborator. For creators who live in a browser, having a model that can autonomously browse, research, and draft without constant hand-holding is a genuine time multiplier.”
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