DeepSeek V4-Flash vs gpt-oss-120b

DeepSeek · China  |  OpenAI · US · Updated June 2026

Quick verdict

Pick DeepSeek V4-Flash for exceptional value — artificial analysis intelligence index 52 at just $0.14/$0.28 per million tokens or mit-licensed open weights — free to self-host or run via a western host. Pick gpt-oss-120b for self-hostable on a single 80gb h100 gpu via mxfp4 or configurable reasoning depth (low/medium/high). On a tight budget at scale, gpt-oss-120b is the value pick.

DeepSeek V4-Flash (DeepSeek, China) and gpt-oss-120b (OpenAI, US) line up two different AI ecosystems against each other — a comparison that is as much about cost philosophy and openness as raw capability. DeepSeek V4-Flash is deepSeek's MIT-licensed open-weight model — arguably the best value-per-intelligence available, scoring 52 on the independent AA Index at just $0.14/$0.28 per million tokens. gpt-oss-120b is openAI's open-weight 117B-parameter MoE reasoning model (5.1B active) that runs on a single 80GB GPU and approaches o4-mini on reasoning, coding, and tool use. They diverge most on price and context window — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecDeepSeek V4-Flashgpt-oss-120b
ProviderDeepSeek (China) OpenAI (US)
ReleasedJuly 31, 2026 August 5, 2025
Context window1M (~1,500 pages) 131K (~197 pages)
Price (in/out)$0.14/$0.28 per 1M tokens Open weight (self-host / free)
Open weight?Yes — self-hostable Yes — self-hostable
Modalitiestext, code text, code
SWE-Bench VerifiedNot published 62.4%
MRCR v2 @ 1MNot published Not published

Who wins what

Exceptional value — Artificial Analysis Intelligence Index 52 at just $0.14/$0.28 per million tokens

DeepSeek V4-Flash

Its 1M window holds about 7.6× more than gpt-oss-120b's 131K in a single prompt.

MIT-licensed open weights — free to self-host or run via a Western host

DeepSeek V4-Flash

DeepSeek's MIT-licensed open-weight model — arguably the best value-per-intelligence available, scoring 52 on the independent AA Index at just $0.14/$0.28 per million tokens — and it carries the larger 1M context.

1M-token context window

DeepSeek V4-Flash

gpt-oss-120b is comparatively weak here — 131K context and 5.1B active params trail the largest frontier closed models

Self-hostable on a single 80GB H100 GPU via MXFP4

gpt-oss-120b

gpt-oss-120b lists self-hostable on a single 80GB H100 GPU via MXFP4 among its strengths; DeepSeek V4-Flash does not.

Configurable reasoning depth (low/medium/high)

gpt-oss-120b

gpt-oss-120b lists configurable reasoning depth (low/medium/high) among its strengths; DeepSeek V4-Flash does not.

Agentic tool use, function calling, and code execution

gpt-oss-120b

DeepSeek V4-Flash is comparatively weak here — coding/agentic figures like Terminal-Bench 82.7 are DeepSeek's own, not independently reproduced

Lowest cost at scale

gpt-oss-120b

Its weights are open, so at volume you pay for your own hardware instead of DeepSeek V4-Flash's $0.14/$0.28 per 1M tokens.

Largest single-prompt input

DeepSeek V4-Flash

Its 1M window is about 7.6× larger than gpt-oss-120b's 131K, fitting roughly 1,500 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

gpt-oss-120b

At Open weight (self-host / free) it undercuts DeepSeek V4-Flash, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

DeepSeek V4-Flash

Larger 1M window fits more in one prompt.

Anyone whose priority is exceptional value — artificial analysis intelligence index 52 at just $0.14/$0.28 per million tokens

DeepSeek V4-Flash

It is specifically built for that.

Anyone whose priority is self-hostable on a single 80gb h100 gpu via mxfp4

gpt-oss-120b

That is its strongest area.

An enterprise with regional data-residency rules

gpt-oss-120b or DeepSeek V4-Flash

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

DeepSeek V4-Flash: where it fits

DeepSeek's MIT-licensed open-weight model — arguably the best value-per-intelligence available, scoring 52 on the independent AA Index at just $0.14/$0.28 per million tokens. Released July 31, 2026 by DeepSeek, it is built for exceptional value — Artificial Analysis Intelligence Index 52 at just $0.14/$0.28 per million tokens, mIT-licensed open weights — free to self-host or run via a Western host, 1M-token context window, and strong coding and agentic performance for the price (DeepSeek reports 82.7 on Terminal-Bench 2.1).

Its trade-offs are real: coding/agentic figures like Terminal-Bench 82.7 are DeepSeek's own, not independently reproduced, text and code focused — not a full multimodal model, deepSeek's own hosted API stores data in China; self-host or use a Western host for privacy, and below the top frontier models on overall intelligence. At $0.14 in / $0.28 out per million tokens, it sits in the budget price band.

gpt-oss-120b: where it fits

OpenAI's open-weight 117B-parameter MoE reasoning model (5.1B active) that runs on a single 80GB GPU and approaches o4-mini on reasoning, coding, and tool use. Released August 5, 2025 by OpenAI, it is built for self-hostable on a single 80GB H100 GPU via MXFP4, configurable reasoning depth (low/medium/high), agentic tool use, function calling, and code execution, and full chain-of-thought visibility for debugging.

Its trade-offs: text-only, no image, audio, or video input, and 131K context and 5.1B active params trail the largest frontier closed models. As an open-weight model, its running cost is your own hardware rather than a per-token fee.

The bottom line for this matchup

This is less "which is smarter" and more "which ecosystem fits." DeepSeek V4-Flash (China) and gpt-oss-120b (US) differ on pricing philosophy, data-residency, and tooling as much as on raw scores. gpt-oss-120b is the cheaper option, which matters at volume. The pragmatic move is to run one real task through both and judge the outputs against your own constraints — including where your data is allowed to be processed.

Want both DeepSeek V4-Flash and gpt-oss-120b 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 DeepSeek V4-Flash or gpt-oss-120b better for coding?

Public SWE-Bench figures are not available for DeepSeek V4-Flash, so the honest test is your own repository — run an identical real bug through both. By design, DeepSeek V4-Flash leans toward exceptional value — artificial analysis intelligence index 52 at just $0.14/$0.28 per million tokens while gpt-oss-120b leans toward self-hostable on a single 80gb h100 gpu via mxfp4, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, DeepSeek V4-Flash or gpt-oss-120b?

gpt-oss-120b is cheaper — $0.14/$0.28 per 1M tokens vs Open weight (self-host / free).

Which has the bigger context window?

DeepSeek V4-Flash — 1M vs 131K, about 7.6× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both DeepSeek V4-Flash and gpt-oss-120b together?

Yes — a multi-model platform like LumiChats gives you DeepSeek V4-Flash, gpt-oss-120b 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-Flash or gpt-oss-120b?

DeepSeek V4-Flash — released July 31, 2026, about 12 months after gpt-oss-120b.

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.