DeepSeek V4.1 Flash vs GLM 5
DeepSeek · China | Z.ai · China · Updated June 2026
Quick verdict
Pick DeepSeek V4.1 Flash for software engineering (deepswe v1.1: 74.2, essentially level with claude opus 5's 74.0) or 1m-token context window at a fraction of frontier pricing ($0.15/$0.60 per million tokens off-peak). Pick GLM 5 for agentic planning and long-horizon coding workflows or complex systems design and backend reasoning. On a tight budget at scale, DeepSeek V4.1 Flash is the value pick.
DeepSeek V4.1 Flash (DeepSeek) and GLM 5 (Z.ai) are two of the models people most often weigh against each other in 2026. DeepSeek V4.1 Flash is deepSeek's September 2026 flash-tier update adds native vision and a 1M-token window to its cost-efficient V4 line, at $0.15/$0.60 per million tokens. 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 and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: DeepSeek V4.1 Flash is about 6.7× cheaper on input ($0.15/$0.6 per 1M tokens vs $1/$3.2 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
- ▸Context window: DeepSeek V4.1 Flash holds 5.2× more — 1.05M tokens (~1,573 pages) vs 200K (~300 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
- ▸Recency: DeepSeek V4.1 Flash is the newer model by about 7 months (released September 10, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | DeepSeek V4.1 Flash | GLM 5 |
|---|---|---|
| Provider | DeepSeek (China) | Z.ai (China) |
| Released | September 10, 2026 | February 12, 2026 |
| Context window | 1.05M tokens (~1,573 pages) | 200K (~300 pages) |
| Price (in/out) | $0.15/$0.6 per 1M tokens | $1/$3.2 per 1M tokens |
| Open weight? | Yes — self-hostable | Yes — self-hostable |
| Modalities | text, image | text, code |
| SWE-Bench Verified | Not published | 77.8% |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
Software engineering (DeepSWE v1.1: 74.2, essentially level with Claude Opus 5's 74.0)
DeepSeek V4.1 Flash
DeepSeek's September 2026 flash-tier update adds native vision and a 1M-token window to its cost-efficient V4 line, at $0.15/$0.60 per million tokens — and it runs cheaper at $0.15/$0.6 per 1M tokens.
1M-token context window at a fraction of frontier pricing ($0.15/$0.60 per million tokens off-peak)
DeepSeek V4.1 Flash
Its 1.05M tokens window holds about 5.2× more than GLM 5's 200K in a single prompt.
Native multimodal vision, added over the text-only V4-Flash it replaces on most traffic
DeepSeek V4.1 Flash
DeepSeek's September 2026 flash-tier update adds native vision and a 1M-token window to its cost-efficient V4 line, at $0.15/$0.60 per million tokens — and it carries the larger 1.05M tokens context.
Agentic planning and long-horizon coding workflows
GLM 5
GLM 5 lists agentic planning and long-horizon coding workflows among its strengths; DeepSeek V4.1 Flash does not.
Complex systems design and backend reasoning
GLM 5
DeepSeek V4.1 Flash is comparatively weak here — positioned as a cost/speed tier, not a frontier-reasoning flagship — DeepSeek kept V4-Pro running in parallel rather than replacing it outright
Iterative self-correction on autonomous tasks
GLM 5
GLM 5 lists iterative self-correction on autonomous tasks among its strengths; DeepSeek V4.1 Flash does not.
Lowest cost at scale
DeepSeek V4.1 Flash
At $0.15/$0.6 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
DeepSeek V4.1 Flash
Its 1.05M tokens window is about 5.2× larger than GLM 5's 200K, fitting roughly 1,573 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ DeepSeek V4.1 Flash
At $0.15/$0.6 per 1M tokens it undercuts GLM 5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ DeepSeek V4.1 Flash
Larger 1.05M tokens window fits more in one prompt.
Anyone whose priority is software engineering (deepswe v1.1: 74.2, essentially level with claude opus 5's 74.0)
→ DeepSeek V4.1 Flash
It is specifically built for that.
Anyone whose priority is agentic planning and long-horizon coding workflows
→ GLM 5
That is its strongest area.
DeepSeek V4.1 Flash: where it fits
DeepSeek's September 2026 flash-tier update adds native vision and a 1M-token window to its cost-efficient V4 line, at $0.15/$0.60 per million tokens. Released September 10, 2026 by DeepSeek, it is built for software engineering (DeepSWE v1.1: 74.2, essentially level with Claude Opus 5's 74.0), 1M-token context window at a fraction of frontier pricing ($0.15/$0.60 per million tokens off-peak), native multimodal vision, added over the text-only V4-Flash it replaces on most traffic, and mIT-licensed open weights, self-hostable.
Its trade-offs are real: the $0.15/$0.60 pricing is an off-peak rate — cost reportedly doubles during peak-demand hours, new Causal Encoder-Decoder architecture (8B active for input, 16B for output) is unproven at broader scale versus DeepSeek's mainline V4/V4-Pro line, and positioned as a cost/speed tier, not a frontier-reasoning flagship — DeepSeek kept V4-Pro running in parallel rather than replacing it outright. At $0.15 in / $0.6 out per million tokens, it sits in the budget 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 12, 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
DeepSeek V4.1 Flash and GLM 5 overlap enough that the right pick depends on your specific job. DeepSeek V4.1 Flash costs less per token; DeepSeek V4.1 Flash holds the larger context; and each leads in its own area — DeepSeek V4.1 Flash for software engineering (deepswe v1.1: 74.2, essentially level with claude opus 5's 74.0), GLM 5 for agentic planning and long-horizon coding workflows. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both DeepSeek V4.1 Flash 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 pricingFrequently asked questions
Is DeepSeek V4.1 Flash or GLM 5 better for coding?
Public SWE-Bench figures are not available for DeepSeek V4.1 Flash, so the honest test is your own repository — run an identical real bug through both. By design, DeepSeek V4.1 Flash leans toward software engineering (deepswe v1.1: 74.2, essentially level with claude opus 5's 74.0) 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, DeepSeek V4.1 Flash or GLM 5?
DeepSeek V4.1 Flash is cheaper — $0.15/$0.6 per 1M tokens vs $1/$3.2 per 1M tokens, roughly 6.7× apart on input.
Which has the bigger context window?
DeepSeek V4.1 Flash — 1.05M tokens vs 200K, about 5.2× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both DeepSeek V4.1 Flash and GLM 5 together?
Yes — a multi-model platform like LumiChats gives you DeepSeek V4.1 Flash, 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, DeepSeek V4.1 Flash or GLM 5?
DeepSeek V4.1 Flash — released September 10, 2026, about 7 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.