Colosseum 355B vs Gemma 3 12B (free)
Colosseum 355B (2025) and Gemma 3 12B (free) (2026) are compact production models from iGenius and Google DeepMind. Colosseum 355B ships a 131K-token context window, while Gemma 3 12B (free) ships a 33K-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing. The goal is to make the tradeoff clear before deeper testing.
Gemma 3 12B (free) is safer overall; choose Colosseum 355B when long-context analysis matters.
Decision scorecard
Local evidence first| Signal | Colosseum 355B | Gemma 3 12B (free) |
|---|---|---|
| Decision fit | Long context | Classification and JSON / Tool use |
| Context window | 131K | 33K |
| Cheapest output | - | $0.13/1M tokens |
| Provider routes | 0 tracked | 3 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Colosseum 355B has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Local decision data tags Colosseum 355B for Long context.
- Gemma 3 12B (free) has broader tracked provider coverage for fallback and procurement flexibility.
- Gemma 3 12B (free) uniquely exposes Structured outputs in local model data.
- Local decision data tags Gemma 3 12B (free) for Classification and JSON / Tool use.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
Colosseum 355B
Unavailable
No complete token price in local provider data
Gemma 3 12B (free)
$64.50
Cheapest tracked route: OpenRouter
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Colosseum 355B and Gemma 3 12B (free); plan for SDK, billing, or endpoint changes.
- Gemma 3 12B (free) adds Structured outputs in local capability data.
- No overlapping tracked provider route is sourced for Gemma 3 12B (free) and Colosseum 355B; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Structured outputs before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-03-10 | 2026-01-01 |
| Context window | 131K | 33K |
| Parameters | 355B | — |
| Architecture | - | decoder only |
| License | Proprietary | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Colosseum 355B | Gemma 3 12B (free) |
|---|---|---|
| Input price | - | $0.04/1M tokens |
| Output price | - | $0.13/1M tokens |
| Providers | - |
Capabilities
| Capability | Colosseum 355B | Gemma 3 12B (free) |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | Yes |
| Code execution | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on structured outputs: Gemma 3 12B (free). Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: Colosseum 355B has no token price sourced yet and Gemma 3 12B (free) has $0.04/1M input tokens. Provider availability is 0 tracked routes versus 3. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Colosseum 355B when long-context analysis and larger context windows are central to the workload. Choose Gemma 3 12B (free) when provider fit and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency. For teams standardizing a stack, that distinction is often the difference between a benchmark win and a reliable deployment.
FAQ
Which has a larger context window, Colosseum 355B or Gemma 3 12B (free)?
Colosseum 355B supports 131K tokens, while Gemma 3 12B (free) supports 33K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Colosseum 355B or Gemma 3 12B (free) open source?
Colosseum 355B is listed under Proprietary. Gemma 3 12B (free) is listed under Open Source. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for structured outputs, Colosseum 355B or Gemma 3 12B (free)?
Gemma 3 12B (free) has the clearer documented structured outputs signal in this comparison. If structured outputs is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Colosseum 355B and Gemma 3 12B (free)?
Colosseum 355B is available on the tracked providers still being sourced. Gemma 3 12B (free) is available on AWS Bedrock, OpenRouter, and GCP Vertex AI. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick Colosseum 355B over Gemma 3 12B (free)?
Gemma 3 12B (free) is safer overall; choose Colosseum 355B when long-context analysis matters. If your workload also depends on long-context analysis, start with Colosseum 355B; if it depends on provider fit, run the same evaluation with Gemma 3 12B (free).
Continue comparing
Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.