DEV CommunityTuesday · September 1, 2026FREE

Spark X2.5-4B & 1.7B: the only on-device models with native 1M-token context — now open source

sparkopen-sourceon-devicellm

Spark X2.5-4B and Spark X2.5-1.7B, two on-device language models, have been released as open source. The announcement, posted on DEV Community, claims these are the only on-device models with native 1M-token context support. This means developers can now access models designed to run directly on devices while handling very long input sequences without external processing. The open-source release allows for integration into various applications, potentially reducing reliance on cloud-based inference. The models are positioned as a significant step for edge AI, offering a combination of on-device efficiency and extensive context window. The exact model names are Spark X2.5-4B and Spark X2.5-1.7B, indicating parameter counts of 4 billion and 1.7 billion respectively. The source does not provide additional technical details, benchmarks, or usage examples, so the digest focuses solely on the release and its stated unique feature.

// why it matters

Developers can now build on-device AI apps with native 1M-token context, a capability previously unavailable in open-source on-device models.

Sources

Primary · DEV Community
▸ Read original at dev.to

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