Claude Sonnet 5 vs GLM 5

Anthropic · US  |  Z.ai · China · Updated June 2026

Quick verdict

Pick Claude Sonnet 5 for agentic workflows that plan, use tools, and run autonomously or multi-step coding, debugging, and tool use. Pick GLM 5 for agentic planning and long-horizon coding workflows or complex systems design and backend reasoning. Choose GLM 5 if you need self-hosting or data privacy; Claude Sonnet 5 if you want a managed API.

Claude Sonnet 5 (Anthropic, US) and GLM 5 (Z.ai, China) line up two different AI ecosystems against each other — a comparison that is as much about cost philosophy and openness as raw capability. Claude Sonnet 5 is anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro. GLM 5 is z.ai's flagship open-weight (MIT) MoE foundation model, engineered for complex systems design and long-horizon agentic coding. They diverge most on price, context window and open vs. closed weights — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecClaude Sonnet 5GLM 5
ProviderAnthropic (US) Z.ai (China)
ReleasedJune 30, 2026 February 11, 2026
Context window1M (~1,500 pages) 200K (~300 pages)
Price (in/out)$3/$15 per 1M tokens $1/$3.2 per 1M tokens
Open weight?No — API only Yes — self-hostable
Modalitiestext, image, code text, code
SWE-Bench VerifiedNot published 77.8%
MRCR v2 @ 1MNot published Not published

Who wins what

Agentic workflows that plan, use tools, and run autonomously

Claude Sonnet 5

A core design strength of Claude Sonnet 5.

Multi-step coding, debugging, and tool use

Claude Sonnet 5

A core design strength of Claude Sonnet 5.

Everyday professional and knowledge work

Claude Sonnet 5

A core design strength of Claude Sonnet 5.

Agentic planning and long-horizon coding workflows

GLM 5

A core design strength of GLM 5.

Complex systems design and backend reasoning

GLM 5

A core design strength of GLM 5.

Iterative self-correction on autonomous tasks

GLM 5

A core design strength of GLM 5.

Lowest cost at scale

GLM 5

At $1/$3.2 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Largest single-prompt input

Claude Sonnet 5

Its 1M window is about 5× larger, fitting roughly 1,500 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

GLM 5

At $1/$3.2 per 1M tokens it undercuts Claude Sonnet 5, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

Claude Sonnet 5

Larger 1M window fits more in one prompt.

A team with data-privacy or self-hosting needs

GLM 5

Open weights let you run it on your own hardware; Claude Sonnet 5 is API-only.

Anyone whose priority is agentic workflows that plan, use tools, and run autonomously

Claude Sonnet 5

It is specifically built for that.

Anyone whose priority is agentic planning and long-horizon coding workflows

GLM 5

That is its strongest area.

An enterprise with regional data-residency rules

Claude Sonnet 5 or GLM 5

Origin (US vs China) affects where data is processed and which compliance regime applies — check the provider's terms for your region.

Claude Sonnet 5: where it fits

Anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro. Released June 30, 2026 by Anthropic, it is built for agentic workflows that plan, use tools, and run autonomously, multi-step coding, debugging, and tool use, everyday professional and knowledge work, and long-document analysis and reasoning.

Its trade-offs are real: lower peak accuracy than Opus 4.8 on the hardest tasks, and an updated tokenizer that can use 1.0-1.35x more tokens for the same text. At $3 in / $15 out per million tokens, it sits in the mid price band.

GLM 5: where it fits

Z.ai's flagship open-weight (MIT) MoE foundation model, engineered for complex systems design and long-horizon agentic coding. Released February 11, 2026 by Z.ai, it is built for agentic planning and long-horizon coding workflows, complex systems design and backend reasoning, iterative self-correction on autonomous tasks, and open weights under the permissive MIT license.

Its trade-offs: 200K context trails 1M-context rivals, and quickly superseded by GLM-5.1 and GLM-5.2. At $1 in / $3.2 out per million tokens, it sits in the budget price band.

The bottom line for this matchup

The defining split here is open vs. closed. GLM 5 gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. Claude Sonnet 5 gives you a managed, always-updated API with no infrastructure to run. Teams with GPUs, privacy requirements, or huge volume often favour the open model; teams that want zero ops and the latest capabilities favour the closed one. Capability is close enough that this operational question, not the benchmark, usually decides it.

Want both Claude Sonnet 5 and GLM 5 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.

See pricing

Frequently asked questions

Is Claude Sonnet 5 or GLM 5 better for coding?

Public SWE-Bench figures are not available for Claude Sonnet 5, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 5 leans toward agentic workflows that plan, use tools, and run autonomously while GLM 5 leans toward agentic planning and long-horizon coding workflows, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, Claude Sonnet 5 or GLM 5?

GLM 5 is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while Claude Sonnet 5 is API-metered at $3/$15 per 1M tokens. For most teams without GPUs, the API model is cheaper to start; at very high volume, self-hosting can win.

Which has the bigger context window?

Claude Sonnet 5 — 1M vs 200K, about 5× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both Claude Sonnet 5 and GLM 5 together?

Yes — a multi-model platform like LumiChats gives you Claude Sonnet 5, GLM 5 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.

Which is newer, Claude Sonnet 5 or GLM 5?

Claude Sonnet 5 — released June 30, 2026, about 5 months after GLM 5.

Related comparisons

Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.