API cost decision in 10 seconds

NewUnion Alpha vs NewFugu Ultra v2

Pick Union Alpha for lower cost; pick Fugu Ultra v2 only if the larger context window matters more.

Page updated: 2026-09-16T15:08:45Z Data confirmed: 2026-09-16T16:08:25Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Union Alpha for lower cost; pick Fugu Ultra v2 only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $20 for Fugu Ultra v2, saving $20 (100% lower).

Cost-first pickUnion Alpha

Context-first pickFugu Ultra v2

Sample savings$20100%

10x traffic gap$200

Fugu Ultra v2 has more context, but Union Alpha saves $20 on the standard workload. At 10x that traffic, the same price gap is about $200. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Union Alpha stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	Union Alpha	Fugu Ultra v2
Input-heavy / RAG	5M input + 500K output	Union Alpha	$0	$40
Balanced workload	1M input + 1M output	Union Alpha	$0	$35
Output-heavy chatbot	1M input + 5M output	Union Alpha	$0	$155

Cheaper input Union Alpha $0 vs $5 / 1M

Union Alpha is free for input tokens while Fugu Ultra v2 costs $5 per 1M tokens.

Cheaper output Union Alpha $0 vs $30 / 1M

Union Alpha is free for output tokens while Fugu Ultra v2 costs $30 per 1M tokens.

Larger context Fugu Ultra v2 262.14K vs 1M

Fugu Ultra v2 has 737.86K more context (3.81x larger).

Sample workload Union Alpha $0 vs $20

Union Alpha is free for the standard workload while the other model is estimated at $20.

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Union Alpha Calculating… Estimated API cost

Fugu Ultra v2 Calculating… Estimated API cost

Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

Union Alpha has the lower input price; Union Alpha has the lower output price; Fugu Ultra v2 offers the larger context window. For the 1M input plus 500K output sample, Union Alpha is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $0 for Union Alpha and $20 for Fugu Ultra v2.

Best Fit

Choose Union Alpha when you care most about lower input-token price, and lower output-token price.

Choose Fugu Ultra v2 when you care most about larger context window.

Decision Notes

On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $20 for Fugu Ultra v2, saving $20 (100% lower).
Union Alpha is free for the standard workload while the other model is estimated at $20.
Union Alpha is free for input tokens while Fugu Ultra v2 costs $5 per 1M tokens.
Union Alpha is free for output tokens while Fugu Ultra v2 costs $30 per 1M tokens.
Fugu Ultra v2 has 737.86K more context (3.81x larger).

Head-to-Head Specs

Feature	NewUnion Alpha (stealth)	NewFugu Ultra v2 (Sakana)
Input Price prompt tokens per 1M	$0	$5
Completion Price per 1M tokens	$0	$30
Sample Workload Cost 1M input + 500K output	$0	$20
Context Window	262.14K	1M
Release Date	2026-09-16	2026-09-11

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Union Alpha	On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $20 for Fugu Ultra v2, saving $20 (100% lower).
High-volume input processing	Union Alpha	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Union Alpha	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Fugu Ultra v2	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

Sakana Namazu can replace Fugu Ultra v2 when lower sample workload cost matters most: $2.95.
Fugu Max can replace Fugu Ultra v2 when lower sample workload cost matters most: $5.

Larger context near this budget

Grok 4.20 Multi-Agent offers 2M context with $2.5 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
DeepSeek V4 Flash 0731 offers 1.31M context with $0.12 sample workload cost.
GLM 5.3 Flash offers 1.31M context with $0.24 sample workload cost.

Popular competitors

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DeepSeek V4 Flash 0731 · DeepSeek · #4

Cheaper alternatives

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Larger context alternatives

Find models with larger context windows for RAG, long documents, and codebase review.

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Provider catalogs

Compare models within provider hubs before choosing a final API vendor.

Open provider hubs

stealth catalog

Review all tracked stealth models before deciding whether this matchup is the right shortlist.

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Sakana catalog

Check other Sakana models with comparable pricing, context, or release timing.

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Union Alpha

Union Alpha is a multimodal model built for research, coding, and agentic workflows, while delivering frontier-level performance across a broad range of general-purpose tasks. Union Alpha is a stealth model....

Fugu Ultra v2

Fugu Ultra v2 is the higher-performance model in Sakana AI's Fugu family. Rather than a single monolithic model, Fugu is a learned multi-agent orchestration system: a language model trained to...