Jamba2 Mini
Jamba2 Mini is the larger of the two January 2026 Jamba2 releases. Its mixture-of-experts design activates 12 billion of 52 billion parameters for each token.
How Jamba2 Mini was trained
The model starts from the Jamba 1.5 pretraining stage. AI21 added 500 billion tokens of mathematics, code, web text and long documents. Later stages included supervised tuning, preference optimization and reinforcement learning. State passing during training helped the model handle long sequences.AI21-Jamba2-Mini official model card
Which API name selects this model
AI21 maps jamba-mini and jamba-mini-2 to jamba-mini-2-2026-01. These are aliases for this release, not additional models.AI21 Jamba versions, aliases and API deprecations
Practical guidance. Pin the dated name when comparing outputs across deployments. A moving alias can select a different release after the provider updates its service.
Active parameters do not set the memory budget
The public weights use Apache 2.0. AI21 recommends vLLM 0.12 or later for the published serving example and also distributes an FP8 export.AI21-Jamba2-Mini official model card
Practical guidance. The 12-billion active count describes token computation. A self-hosted server still needs to store the model's experts. Measure memory and latency with the intended document length, batch size and weight format.
Specifications & access
| Detail | Value and conditions |
|---|---|
| Launch date | |
| Access | API, Downloadable |
| Model identifiers | AI21-Jamba2-Miniai21labs/AI21-Jamba2-MiniAI21-Jamba2-Mini-FP8jamba-minijamba-mini-2jamba-mini-2-2026-01 |
| Context window | 262,144 tokens Maximum position count in the published weight configuration; deployed limits depend on the serving setup. AI21-Jamba2-Mini configuration |
| Parameters | 52 billion total; 12 billion activeAI21-Jamba2-Mini official model card |
| Weight license | Apache 2.0AI21-Jamba2-Mini official model card |
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