DeepSeek · AI model
DeepSeek-V4.1-Flash
DeepSeek's current Flash model (API: deepseek-flash), served since 2026-10-17 as version DeepSeek-V4.1-Flash-1017 in the API, web chat and app. Accepts text and images, with a 1M-token context, up to 384K output tokens and a thinking mode with low, high and max effort. Weights are MIT-licensed.
Last verified Available 15 sources
Key specs
- Provider
- DeepSeek
- Family
- DeepSeek-V4.1
- API identifier
- deepseek-flash
- Availability
- Available
- Release date
- 2026-09-10
- License
- Open source (MIT License)
- Context window
- 1,048,576 tokens
- Max output
- 393,216 tokens
- API access
- Yes
- Consumer app
- Yes
Capabilities
Inputs
- Text input Yes
- Image input Yes JPEG, PNG, GIF and WebP; up to 600 images per request; up to 8192 px per side (4096 px when a request contains 15 or more images); each image counts as at most 1024 tokens; images in system or assistant messages return a 400 error.
- Audio input No The Chat Completions reference lists only text, image_url and file (image data) content parts.
- Video input No The Chat Completions reference lists only text, image_url and file (image data) content parts.
- File input No The Anthropic-compatible API marks document content blocks as not supported, the Responses API states that file inputs are not supported, and the Files API accepts only images (JPEG, PNG, GIF, WebP, up to 64 MiB).
Outputs
- Text output Yes
- Image output No The model card states that the model processes images and text and generates text.
- Audio output No The model card states that the model processes images and text and generates text.
Features
- Reasoning Optional Thinking is on by default with effort 'high'. Effort can be low, high or max. Thinking can be switched off with thinking.type=disabled, or with reasoning_effort=none (Chat Completions reference) / reasoning.effort=none (Responses API).
- Tool calling Yes Function tools only (Chat Completions reference). Works in thinking and non-thinking mode; required or named tool_choice is not supported in thinking mode. Strict mode is in beta.
- Web search Partial No built-in search tool: Chat Completions takes function tools only and the Responses API ignores web_search for deepseek-flash. Claude Code's Web Search works via the Anthropic-compatible endpoint (extra token costs plus Search API billing). Separate Search/Fetch endpoints exist since 2026-10-17.
"Unknown" means we have not verified this capability yet; it does not mean the model lacks it.
Pricing
Estimate your monthly cost →| Dimension | Tier | Price | Since | Verified | Source |
|---|---|---|---|---|---|
| Input tokens | base | $0.30 per 1M tokens | 2026-10-12 | 2026-10-25 | Models & Pricing | DeepSeek API Docs Cache miss, peak rate. Peak hours are 01:00-04:00 and 06:00-10:00 UTC, Monday to Friday, excluding Chinese public holidays; all other hours are off-peak. Image inputs are converted to tokens (at most 1024 per image) and billed together with text tokens (Vision guide). |
| Cached input tokens | base | $0.006 per 1M tokens | 2026-10-12 | 2026-10-25 | Models & Pricing | DeepSeek API Docs Cache hit, peak rate. |
| Output tokens | base | $1.20 per 1M tokens | 2026-10-12 | 2026-10-25 | Models & Pricing | DeepSeek API Docs Peak rate. |
| Tool and search requests | Search / Fetch API | $0.75 per 1,000 requests | 2026-10-25 | 2026-10-25 | Models & Pricing | DeepSeek API Docs Separate Search and Fetch API endpoints: per 1,000 successful requests each; failed, empty and timed-out requests are not billed. Calls by server-side tools in DeepSeek Harness, Claude Code or Codex are free until billing starts at 16:00 UTC on 2026-10-31 (00:00 Beijing time, 2026-11-01). |
| Other | Off-peak cached input | $0.003 per 1M units | 2026-10-12 | 2026-10-25 | Models & Pricing | DeepSeek API Docs Cache hit. Off-peak rate (half of the peak rate): all hours outside 01:00-04:00 and 06:00-10:00 UTC Monday to Friday, including weekends and Chinese public holidays |
| Off-peak input | $0.15 per 1M units | 2026-10-12 | 2026-10-25 | Models & Pricing | DeepSeek API Docs Cache miss. Off-peak rate (half of the peak rate): all hours outside 01:00-04:00 and 06:00-10:00 UTC Monday to Friday, including weekends and Chinese public holidays | |
| Off-peak output | $0.60 per 1M units | 2026-10-12 | 2026-10-25 | Models & Pricing | DeepSeek API Docs Off-peak rate (half of the peak rate): all hours outside 01:00-04:00 and 06:00-10:00 UTC Monday to Friday, including weekends and Chinese public holidays |
Prices are shown in the currency the provider publishes; we never convert currencies.
Price history (7 entries)
| Dimension | Tier | Price | From | Until |
|---|---|---|---|---|
| Input tokens | base | $0.30 per 1M tokens | 2026-10-12 | current |
| Cached input tokens | base | $0.006 per 1M tokens | 2026-10-12 | current |
| Output tokens | base | $1.20 per 1M tokens | 2026-10-12 | current |
| Tool and search requests | Search / Fetch API | $0.75 per 1,000 requests | 2026-10-25 | current |
| Other | Off-peak cached input | $0.003 per 1M units | 2026-10-12 | current |
| Other | Off-peak input | $0.15 per 1M units | 2026-10-12 | current |
| Other | Off-peak output | $0.60 per 1M units | 2026-10-12 | current |
Benchmarks
| Benchmark | Setting | Score | Reported by | Measured | Verified | Source |
|---|---|---|---|---|---|---|
| AutomationBench % tasks completed correctly, higher is better | public evaluation set, v1.0.6, Pass@1; max effort; official scaffold | 54.8 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) |
| snapshot DeepSeek-V4.1-Flash-1017; v1.0.6, task set not stated (probably the public evaluation set); effort not stated | 60.5 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash-1017 model card (Hugging Face) | |
| DeepSWE v1.1 % resolved (pass@1), higher is better | Resolved, N=8 samples per task; max effort; Claude Code v2.1.251 | 69.8 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) |
| Resolved, N=8 samples per task; max effort; Codex v0.147.0 | 65.6 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) | |
| Resolved, N=8 samples per task; max effort; DeepSeek Harness (Minimal mode) | 72.6 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) | |
| Resolved, N=8 samples per task; max effort; DeepSeek Harness (PTC mode) | 67.6 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) | |
| Resolved, N=8 samples per task; max effort; DeepSeek Harness (Standard mode) | 70.5 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) | |
| Resolved, N=8 samples per task; max effort; OpenCode v1.18.15 | 65.5 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) | |
| Resolved, N=8 samples per task; max effort; Pi v0.84.2 | 66.2 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) | |
| Resolved, N=8 samples per task; max effort; mini-SWE harness (mini-swe-agent) | 74.2 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash model card (Hugging Face) | |
| Resolved; reasoning effort 25 (of 100); harness not stated | 66 % | Self-reported | — | 2026-10-25 | DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17) | |
| snapshot DeepSeek-V4.1-Flash-1017; v1.1; effort not stated; Mini-SWE-V2 harness | 77 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash-1017 model card (Hugging Face) | |
| FrontierMath Tiers 1-3 (v2) accuracy %, higher is better | max effort; Epoch harness (Python tool) | 67.4 % | Third party | 2026-10-08 | 2026-10-25 | FrontierMath Tiers 1-3 (v2) leaderboard (Epoch AI) |
| snapshot DeepSeek-V4.1-Flash-1017; max effort; Epoch harness (Python tool) | 71.2 % | Third party | 2026-10-19 | 2026-10-25 | FrontierMath Tiers 1-3 (v2) leaderboard (Epoch AI) | |
| GDPval-AA v2.1 Elo, higher is better | max effort; Stirrup agent loop (shell + web browsing) | 1,600 Elo | Third party | — | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) |
| non-reasoning; Stirrup agent loop (shell + web browsing) | 1,340 Elo | Third party | — | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) | |
| snapshot DeepSeek-V4.1-Flash-1017; max effort; Stirrup agent loop (shell + web browsing) | 1,746 Elo | Third party | — | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) | |
| Humanity's Last Exam accuracy %, higher is better | no tools, full set, Pass@1; max effort | 36.8 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash model card (Hugging Face) |
| no tools, text-only subset, Pass@1; max effort | 39.1 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash model card (Hugging Face) | |
| snapshot DeepSeek-V4.1-Flash-1017; no tools, full set; effort not stated | 42.6 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash-1017 model card (Hugging Face) | |
| snapshot DeepSeek-V4.1-Flash-1017; no tools, text-only subset; effort not stated | 44 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash-1017 model card (Hugging Face) | |
| with tools, Pass@1; max effort | 63.9 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash model card (Hugging Face) | |
| Terminal-Bench 4.0 % tasks resolved, higher is better | Pass@1; max effort (reasoning_effort=100); DeepSeek Harness (Minimal mode), 1M-token context | 31.2 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash model card (Hugging Face) |
| snapshot DeepSeek-V4.1-Flash-1017; effort not stated; Claude Code harness | 42.3 % | Self-reported | — | 2026-10-25 | deepseek-ai/DeepSeek-V4.1-Flash-1017 model card (Hugging Face) | |
| Text Arena Arena score, higher is better | Overall, style control on; max effort | 1,476 | Third party | 2026-10-23 | 2026-10-25 | Text Arena leaderboard (Arena) |
Leaderboard versions (for example 1.0.5 and 1.0.6) are not comparable. Some results use fallback routing for refused steps: for "Claude Fable 5.1 (with Opus 5 Fallback)", Opus 5 handled 260 of 657 tasks. Artificial Analysis runs a separate leaderboard, AutomationBench-AA, which uses a guardrail-adjusted metric; its scores are not comparable with Zapier's. The partial_credit metric is for diagnostics only. The leaderboard shows no per-row evaluation dates.
The official leaderboard uses mini-swe-agent for all models and shows whole-number percentages with margins of about ±1 to ±6 points. Providers often report scores from their own scaffolds or effort settings; DeepSeek reports 65.5% to 74.2% for the same model depending on the scaffold. DeepSWE v1 scores are not comparable with v1.1. With only 113 tasks, small differences are within noise.
FrontierMath was developed with funding from OpenAI, which has exclusive access to a subset of the problems. Scores from v1 and from Tier 4 (a separate 43-problem expansion set) are not comparable with Tiers 1-3 (v2). The best models score about 94%, so the benchmark separates mid-size models better than it separates frontier models. Epoch's numbers come from its own harness (Python tool, 1M-token limit), which can differ from providers' internal setups. Margins are about ±1.4 to ±2.6 points.
Elo is a relative rating: values change as models are added and the scale is re-anchored, so always store the date a rating was read. For example, Anthropic's launch page gives 1846 for Claude Opus 5.5, while the leaderboard on 2026-10-12 shows 1866 (Max, Default Fallback). Earlier versions (Google cites "GDPVal-AA v2") are not comparable. Judging is done by an LLM, not by human experts. Anthropic models are listed with "Default Fallback", meaning refused steps are routed to a fallback model. AA-Briefcase and GDP.pdf are separate evaluations.
Results differ a lot by setting: with tools versus without tools (Anthropic reports 45.9% without tools and 57.4% with tools for Claude Haiku 5.5), and the full set versus the text-only subset. Providers use different judge models and harnesses (Scale uses o3-mini; Alibaba states GPT-4o). Derived sets such as HLE-Verified (a third-party revision with 1,811 scored items), HLE-Rolling and HLE-Diamond are different item sets and are not comparable. The questions are public, so contamination is possible, and community reviews have reported flawed items.
Scores depend heavily on the agent harness (for example Claude Code, Codex, Grok Build or mini-SWE-agent) and on the reasoning effort, so the same model appears several times on the leaderboard. Leaderboard rows are often submitted by the organisation that builds the agent. Providers' own runs can differ from the leaderboard: Anthropic reports 66.4% for Claude Opus 5.5 at max effort, while the leaderboard lists 64.8% ± 3.1%. Versions 2.0, 2.1 and 3.0 and Artificial Analysis' "Terminal-Bench Hard" use different task sets and are not comparable with 4.0. Margins are about ±3 points.
Scores measure voter preference, which can be influenced by answer style and length. The leaderboard offers a style-control adjustment, so record which view was used. Scores shift with every update, so a value is only meaningful together with its leaderboard date. Entries marked "Preliminary" or with few votes have wide confidence intervals. The same model can appear several times with different reasoning-effort suffixes (for example -high or -max). Category views (Coding, Math, Creative Writing and others) are different rankings from Overall.
One row per result, without rank numbers: each result was measured under its own setting (effort level, harness, tools, test version), as stated by the source, and scores compare only within the same setting. Self-reported results come from the provider and have not been reproduced independently.
Rankings
- #1 of 42 in Best AI API as of 2026-10-26
- #1 of 39 in Best AI for business as of 2026-10-26
- #1 of 20 in Best AI for coding as of 2026-10-27
- #8 of 14 in Best AI for research as of 2026-10-26
- #19 of 26 in Best AI for students as of 2026-10-26
Derived from our published ranking snapshots; each ranking explains its criteria and weights.
Compare DeepSeek-V4.1-Flash
Guides
- AI token pricing explained: input, output, cached and batch rates
- Reasoning models explained: thinking modes, effort and cost
- Multimodal AI explained: image, audio, video and file inputs, and what they cost
- Context windows explained: limits, long-context pricing and recall
- How to choose an AI model: a practical decision framework
About DeepSeek-V4.1-Flash
DeepSeek-V4.1-Flash was released on 2026-09-10. DeepSeek describes it as the smallest model in its new architecture family, with native visual understanding. At release it was described as a 552B-parameter Mixture-of-Experts model with a Causal Encoder-Decoder design that activates 8B parameters for input and 16B for output.
On 2026-10-17 DeepSeek replaced it with DeepSeek-V4.1-Flash-1017, which its model card calls a minor update to V4.1-Flash. The API name deepseek-flash, the calling method and the prices stayed the same, and the web chat and app switched to the new version at the same time. DeepSeek reports higher benchmark scores than the previous version, shorter task run times and shorter outputs, and says the update improves building complete projects such as games and 3D scenes. The 1017 weights are published separately on Hugging Face under the MIT License.
The legacy API names deepseek-v4-flash and deepseek-v4-flash-vision-exp are still accepted and are served by DeepSeek-V4.1-Flash-1017 at Flash prices.
Strengths and weaknesses
Strengths
- 1M-token context window and up to 384K (393,216) output tokens
- Accepts images (JPEG, PNG, GIF, WebP), up to 600 per request, through the Chat Completions, Responses and Anthropic-compatible APIs
- Lower prices than deepseek-v4-pro ($0.30 per 1M input tokens and $1.20 per 1M output tokens at peak; half that off-peak) and a higher concurrency limit (2,500 vs 500)
- Weights published on Hugging Face under the MIT License
Weaknesses
- No document (PDF), audio or video input; the Files API accepts only images
- FIM completion (beta) works only in non-thinking mode, and required or named tool_choice is not supported in thinking mode
- Only function tools are supported; built-in tools such as web_search or code_interpreter in the Responses API are ignored
Sources
- DeepSeek-V4.1-Flash config.json (Hugging Face)
- Chat Completions API | DeepSeek API Docs
- DeepSeek-V4.1-Flash Release 2026/09/10 | DeepSeek API Docs
- deepseek-ai/DeepSeek-V4.1-Flash model card (Hugging Face)
- Models & Pricing | DeepSeek API Docs
- Vision | DeepSeek API Docs
- Anthropic API | DeepSeek API Docs
- Thinking Mode | DeepSeek API Docs
- Integrate with Claude Code | DeepSeek API Docs
- DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression (DeepSeek-AI, arXiv 2609.19969, submitted 2026-09-17)
- FrontierMath Tiers 1-3 (v2) leaderboard (Epoch AI)
- GDPval-AA v2.1 Leaderboard (Artificial Analysis)
- Text Arena leaderboard (Arena)
- DeepSeek-V4.1-Flash-1017 config.json (Hugging Face)
- deepseek-ai/DeepSeek-V4.1-Flash-1017 model card (Hugging Face)
Last verified Page updated 2026-10-27