Spring 2026 brought two major model releases that drew widespread attention from the AI community: Google's Gemma 4 on April 2, and Anthropic's Claude Mythos Preview a few weeks earlier. Both models have generated significant excitement — but they are fundamentally different things, designed for different purposes, with very different access models.
Here's a clear-headed comparison to help you understand what each model offers and when to use which.
The Core Distinction: Open vs. Closed
Before comparing capabilities, it's worth establishing the foundational difference.
Gemma 4 is an open model. Released under Apache 2.0, it can be downloaded, deployed, fine-tuned, and used commercially by anyone, with no restrictions. Google released it to expand its AI ecosystem and contribute to the research community.
Claude Mythos is a closed, gated model. There are no plans for general public availability. Access is selective and currently prioritized for defensive cybersecurity use cases. Anthropic describes it as "a new class of intelligence built for ambitious projects" — a model designed for specific high-stakes applications, not broad deployment.
This distinction matters more than any benchmark comparison. If you need a model you can deploy today, Gemma 4 is your option. If your specific use case aligns with what Mythos was built for, you can request access and wait.
Licensing and Access
Gemma 4 access options:
- Google Cloud Vertex AI — managed API, usage-based pricing
- LM Studio — local inference on your own hardware, no API costs
- Hugging Face — direct model weight downloads for self-hosted deployment
- Available immediately, no application required
Claude Mythos access options:
- Google Cloud Vertex AI — gated preview, application required
- Amazon Bedrock — gated preview, application required
- Anthropic's preview program — prioritizes cybersecurity use cases
- Not generally available, selective access only
Capability Comparison by Domain
A head-to-head benchmark comparison isn't yet possible — Mythos is in preview and independent evaluations are limited. But based on available information, here's where each model leads.
Where Gemma 4 Excels
Gemma 4's 31B Dense model currently ranks 3rd globally among all open models on the Arena AI text leaderboard, outperforming several models with far larger parameter counts.
All Gemma 4 models natively process video and images. The E2B and E4B edge models add native audio input. Multilingual capability spans 140+ languages with native training. Function calling, structured JSON output, and system instructions are built in. Context windows reach 128K (edge models) and 256K (cloud models).
Where Claude Mythos Excels
Claude Mythos's standout capability is in cybersecurity. Anthropic used it to autonomously discover thousands of zero-day vulnerabilities in major operating systems and browsers — many of which had survived decades of human review and automated scanning.
In autonomous coding and long-horizon agent tasks, Mythos represents what Anthropic calls a "step change" rather than incremental improvement over existing models. For complex, multi-step agentic workflows, Mythos was specifically designed to excel.
Use Case Decision Guide
Integrating AI into your product (chatbots, document processing, image analysis): Gemma 4. It's available now, works commercially, and can be deployed on your own infrastructure.
On-device or edge deployment (mobile apps, embedded systems): Gemma 4 E2B or E4B. Mythos is only accessible via API — it cannot run locally.
Software vulnerability discovery and security research: Mythos is the purpose-built choice, if you can get access. Without access, Gemma 4 31B Dense is a capable alternative for security code review.
Large-scale autonomous codebase refactoring: Mythos was designed for this type of long-horizon agentic task. Practically speaking, Gemma 4 31B is the available option today.
Research, experimentation, rapid prototyping: Gemma 4, without question. Local inference means no API costs and no latency, making the iteration loop much faster.
Multilingual applications for global markets: Gemma 4, with its 140+ language native training.
Cost Considerations
Gemma 4: Local inference has no API costs beyond your hardware. Vertex AI uses consumption-based pricing that scales with usage. Under Apache 2.0, organizations with their own infrastructure can manage costs effectively over time.
Claude Mythos: Pricing has not been publicly disclosed for the preview. When and if generally available, it would likely be priced at or above Claude Opus rates, reflecting its positioning as a top-tier frontier model.
The Bottom Line
Claude Mythos and Gemma 4 are not really competing for the same users. They were built with different goals and for different audiences.
Gemma 4 is the practical choice for developers today: open, immediately accessible, commercially usable, and capable across a wide range of applications. If you're building products that need AI now, Gemma 4 is where to start.
Claude Mythos represents a frontier capability in cybersecurity and high-complexity agentic tasks that has no current open equivalent. Its access is extremely limited today, but it's worth watching — if and when Anthropic expands availability, it will have significant implications for how developers approach security research and autonomous agent design.
For most developers in April 2026, the decision is straightforward: deploy Gemma 4 for what you're building today, and keep an eye on Mythos for what might be possible tomorrow.