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SubQ Review

SubQ is a Large Language Model (LLM) built on a sub-quadratic sparse attention architecture designed for extreme efficiency and performance on very long context tasks.

shipped Jun 18, 2026aifreemium
SubQ - AI tool for subq. Professional illustration showing core functionality and features.
1Processes up to 12 million tokens in a single context window, with a future target of 100 million tokens by Q4.
2Utilizes Subquadratic Sparse Attention (SSA) for linear scaling of compute with context length, achieving O(n) attention complexity.
3Demonstrates up to nearly 1,000x attention compute reduction and runs 56x faster than FlashAttention-2 at 1M tokens.
4Offers an OpenAI-compatible API for developers, supporting streaming and tool use.

SubQ at a Glance

Pricing
freemium
Key Features
Processes up to 12 million tokens in a single context window, with a future target of 100 million tokens by Q4. · Utilizes Subquadratic Sparse Attention (SSA) for linear scaling of compute with context length, achieving O(n) attention complexity. · Demonstrates up to nearly 1,000x attention compute reduction and runs 56x faster than FlashAttention-2 at 1M tokens.
Alternatives
DeepSeek-V3, Mamba (State Space Models), RWKV, LongGen

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Mamba (State Space Models)

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RWKV

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LongGen

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overview

What is SubQ?

SubQ is a Large language model (technology) tool developed by Subquadratic (technology) that enables developers, enterprise teams, data engineers, researchers, and coding agents to perform multi-million token reasoning. It is built on a sub-quadratic sparse attention architecture designed for extreme efficiency and performance on very long context tasks. SubQ's core innovation, Subquadratic Sparse Attention (SSA), allows it to process up to 12 million tokens in a single context window, with a future target of 100 million tokens by Q4. This architecture enables linear scaling of compute with context length, overcoming the quadratic scaling limitations of traditional transformer models. Subquadratic officially launched SubQ on May 5, 2026, securing $29 million in seed funding. The company released SubQ 1.1 Small on June 16, 2026, which is the second iteration of its SSA model, demonstrating near-perfect long-context retrieval up to 12M tokens on the needle-in-a-haystack test. SubQ offers an OpenAI-compatible API for developers, SubQ Code (a command-line coding agent), and SubQ Search (a long-context search tool).

quick facts

Quick Facts

AttributeValue
DeveloperSubquadratic
Business ModelFreemium
PricingFreemium model, specific tiers and usage rates not publicly detailed
PlatformsAPI (OpenAI-compatible), Command-line (SubQ Code)
API AvailableYes
IntegrationsOpenAI-compatible API endpoints
FoundedSubquadratic launched SubQ on May 5, 2026
Funding$29 million in seed funding

features

Key Features of SubQ

SubQ is engineered with a novel sub-quadratic sparse attention architecture to deliver high efficiency and performance for tasks requiring extensive context windows. Its design focuses on overcoming the computational limitations of traditional transformer models.

  • 1Sub-quadratic sparse attention architecture with O(n) attention complexity.
  • 2Maximum context window of 12 million tokens, with a future target of 100 million tokens by Q4.
  • 3OpenAI-compatible API endpoints for seamless developer integration and tool use.
  • 4Near-perfect performance on single-fact retrieval (1M-12M tokens) and multi-task retrieval (128K tokens).
  • 5Achieves up to nearly 1,000x attention compute reduction at 12M tokens compared to dense attention.
  • 6Runs 56x faster than FlashAttention-2 at a 1M-token context window.
  • 7Supports streaming for continuous data processing.
  • 8Enables reasoning across full repositories, long histories, and persistent state without quality loss.

use cases

Who Should Use SubQ?

SubQ is designed for professionals and teams requiring advanced reasoning capabilities over extremely large datasets and long-context documents, particularly where traditional LLMs face limitations due to context window size and computational cost.

  • 1**Developers & Enterprise Teams**: Utilizing the OpenAI-compatible API for custom AI agents and applications that demand multi-million token reasoning.
  • 2**Financial Analysts**: Performing due diligence and analysis across entire collections of financial filings, earnings reports, contracts, and internal records.
  • 3**Legal Professionals**: Analyzing complex legal documents where terms and conditions are defined, qualified, and excepted across numerous pages.
  • 4**Software Engineers**: Loading entire codebases into a single context window for architecture-level reasoning, cross-file refactoring, dependency tracing, and security vulnerability analysis.
  • 5**Researchers**: Ingesting thousands of pages of regulatory filings, medical records, or scientific literature for multi-document analysis, correlation discovery, and deep research workflows.

pricing

SubQ Pricing & Plans

SubQ operates on a freemium business model. While a free tier is available, specific details regarding paid tiers, usage-based pricing, or feature limitations for the freemium model are not publicly disclosed by Subquadratic. The company claims significant cost reductions compared to traditional LLMs, citing a long-context run that would cost approximately $2,600 on Claude Opus 4.7 is claimed to cost around $8 on SubQ, representing a 300x cost reduction at similar accuracy.

  • 1Freemium model with unlisted specific tier details.

competitors

SubQ vs Competitors

SubQ positions itself as a breakthrough in Large language model (technology) architecture by directly addressing the quadratic scaling problem of transformers, which limits context window size and increases cost. It competes with other models focused on long-context efficiency through various architectural innovations.

1
DeepSeek-V3

DeepSeek-V3 utilizes a combination of Multi-head Latent Attention (MLA) and DeepSeek Sparse Attention (DSA) to optimize long-context processing and reduce KV-cache costs.

DeepSeek-V3, like SubQ, focuses on efficient long-context handling through sparse attention mechanisms. While both aim for efficiency, there are discussions in the research community regarding whether DeepSeek's sparse attention implementation achieves a truly sub-quadratic complexity across all layers, a core claim of SubQ's architecture.

2

Mamba is a novel state-space model architecture that achieves linear scaling with sequence length, offering constant memory inference and strong performance on very long sequences without relying on traditional attention mechanisms.

Mamba provides a fundamentally different architectural approach to long-context efficiency compared to SubQ's sparse attention. Both aim for linear scaling and high performance on extended contexts, but Mamba achieves this through recurrent state updates rather than attention approximations.

3
RWKV

RWKV is a recurrent neural network (RNN) architecture that combines the strengths of RNNs (linear scaling, constant memory) with the performance of Transformers, enabling efficient processing of extremely long sequences.

Similar to SubQ, RWKV targets linear scaling for long-context tasks to improve efficiency and performance. However, RWKV achieves this through a recurrent design, contrasting with SubQ's sub-quadratic sparse attention, offering an alternative paradigm for efficient long-sequence modeling.

4
LongGen

LongGen improves both training and inference efficiency for long-context LLMs by integrating context length extension with a GPU-friendly KV cache reduction architecture, utilizing sparse attention patterns and a hybrid layer approach.

LongGen directly competes with SubQ in optimizing LLMs for long contexts and efficiency, employing sparse attention and architectural modifications to reduce computational overhead. While SubQ emphasizes a 'fully subquadratic' architecture, LongGen uses a hybrid approach with a mix of full and efficient attention layers.

Frequently Asked Questions

+What is SubQ?

SubQ is a Large language model (technology) tool developed by Subquadratic (technology) that enables developers, enterprise teams, data engineers, researchers, and coding agents to perform multi-million token reasoning. It is built on a sub-quadratic sparse attention architecture designed for extreme efficiency and performance on very long context tasks.

+Is SubQ free?

SubQ operates on a freemium business model, offering a free tier. Specific details regarding paid tiers or usage rates are not publicly disclosed by Subquadratic.

+What are the main features of SubQ?

SubQ features a sub-quadratic sparse attention architecture, enabling a 12 million token context window with O(n) attention complexity. It offers an OpenAI-compatible API, near-perfect retrieval performance up to 12M tokens, and significant efficiency gains, including up to 1,000x attention compute reduction and 56x faster processing than FlashAttention-2 at 1M tokens.

+Who should use SubQ?

SubQ is designed for developers, enterprise teams, data engineers, researchers, and coding agents. Its primary applications include financial analysis, legal and contract work, software engineering (analyzing entire codebases), multi-document analysis, and long-context search workflows.

+How does SubQ compare to alternatives?

SubQ differentiates itself by addressing the quadratic scaling problem of traditional transformers with its sub-quadratic sparse attention architecture, offering a 12 million token context window and claiming superior efficiency and cost-effectiveness. It contrasts with models like DeepSeek-V3 (different sparse attention implementation), Mamba and RWKV (recurrent/state-space models), and LongGen (hybrid attention approach), all of which also aim for long-context efficiency but through different architectural paradigms. SubQ's context window is significantly larger than leading frontier models like Claude Opus and Gemini 1.5 Pro.

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