Google AI Studio vs Vertex AI vs OpenRouter (2026)

If you search "Google AI Studio vs Vertex AI" in October 2026, half the answers are out of date. In April, Google renamed Vertex AI to the Gemini Enterprise Agent Platform at Cloud Next, and existing Vertex workloads moved under the new name without breaking changes. Meanwhile, a lot of developers who start on AI Studio end up on a third option entirely: OpenRouter, which sells Gemini next to hundreds of other models through one API.

All three let you call Gemini from code. They differ on who pays, who sees your data, and how much setup stands between you and the first request. Here's how to choose, with prices checked against each provider's docs this week.

The short comparison

Google AI Studio: the fastest way to your first Gemini call

Google AI Studio is two things in one: a browser playground for testing prompts, and the front door to the Gemini Developer API. You sign in, click "Get API key," and you're calling the API a few minutes later.

Google's pricing page puts it plainly: AI Studio usage is free of charge in all available regions. That covers the web interface. The API has a separate free tier, and as of this week it covers most of the current lineup: Gemini 3.8 Flash, 3.7 Flash, 3.6 Flash, 3.5 Flash, 3.5 Flash-Lite and 3.1 Flash-Lite, plus the older 2.5 Pro, 2.5 Flash and 2.5 Flash-Lite. The top model, Gemini 3.1 Pro Preview, is paid only, along with the image models.

Google doesn't publish fixed free-tier rate limits anymore. The rate-limit docs say limits depend on your usage tier and that you can see your active limits inside AI Studio. Paid usage is tiered too:

• Tier 1: link an active billing account
• Tier 2: $100 spent and 3 days since your first successful payment
• Tier 3: $1,000 spent and 30 days since your first payment

Paid prices per 1 million tokens, from Google's pricing page:

The Batch API cuts those prices by 50% if you can wait for results.

Note the promotional price on 3.8 Flash. If you're budgeting for 2027, use the post-December rate, which doubles both input and output.

The catch on the free tier: your data. Google's pricing page states that free-tier content is used to improve its products, and paid-tier content is not. That's fine for side projects and public data. It's a deal-breaker for customer records, internal documents, or anything under an NDA. Turn on billing before real user data touches the API.

Gemini Enterprise Agent Platform: Vertex AI under a new name

Google calls the new platform "the evolution of Vertex AI," adding agent building, orchestration and security tooling on top of the model access Vertex already had. If you used Vertex AI before April 2026, your code still runs. The Vertex AI listing in our directory covers the same product.

Google's own migration guide gives the clearest advice on when to use it: most developers should use the Gemini Developer API unless they need specific enterprise controls. The enterprise platform requires a Google Cloud project and authenticates with service accounts instead of API keys. In exchange you get Cloud IAM roles, org-level policies, Cloud billing and audit trails, and your AI spend sits next to the rest of your infrastructure.

Both platforms share one SDK, google-genai for Python and @google/genai for JavaScript. Moving from AI Studio to the enterprise platform is mostly a configuration change, not a rewrite. One limit worth knowing: during its preview, the Interactions API on the enterprise platform only supports the global endpoint, while the Developer API supports multiple regions. If you need a specific region for compliance, confirm support for the exact API you plan to use.

Pick it when: your company already runs on Google Cloud, security needs to approve every vendor, or procurement wants one invoice. Skip it when: you're one developer testing an idea. The project, billing and IAM setup is real friction for zero benefit at that stage.

OpenRouter: one key for every model, Gemini included

OpenRouter is a routing layer. You buy credits once, get one API key, and call models from Google, Anthropic, OpenAI, Meta, Mistral, DeepSeek and many smaller providers. Its quickstart says it handles fallbacks automatically and picks the most cost-effective option for each request.

On pricing, OpenRouter's FAQ says it passes through provider prices with no markup on inference. It earns money on credit purchases instead: 5.5% with a $0.80 minimum by card, or 5% with crypto. On $100 of credits, that's $5.50. If you bring your own provider keys, the first $25,000 of monthly usage carries no BYOK fee on pay-as-you-go, then 5%.

The free models (marked with a :free suffix) are good for testing but tightly capped: 50 requests per day with no credits purchased, rising to 1,000 per day after you've bought at least $10 in credits.

The API is OpenAI-compatible. Point the OpenAI SDK at https://openrouter.ai/api/v1 and most existing code works with a model-name change:

from openai import OpenAI

client = OpenAI(base_url="https://openrouter.ai/api/v1", api_key="YOUR_OPENROUTER_KEY")
resp = client.chat.completions.create(
    model="google/gemini-2.5-flash",
    messages=[{"role": "user", "content": "Summarize this ticket in one line."}],
)
print(resp.choices[0].message.content)

Where OpenRouter loses: you're adding a middleman to every request. Data handling depends on which provider serves the call, so read the provider policies for anything sensitive. Gemini-specific features such as Google's newest native tools can arrive later through a generic OpenAI-shaped API, or not at all. And for pure Gemini usage, the 5.5% credit fee is money you wouldn't pay going direct.

What a real workload costs on each

Take a support-ticket summarizer: 2 million input tokens and 400,000 output tokens a month on Gemini 2.5 Flash.

• AI Studio, paid tier: 2 × $0.30 + 0.4 × $2.50 = $1.60/month. On the free tier it may cost nothing, but Google can use that data, which rules it out for real tickets.
• Enterprise Agent Platform: billed on Google Cloud's price sheet for the same model. Expect a similar figure, plus the time it takes to set up a project and service accounts.
• OpenRouter: the same $1.60 in usage, plus the 5.5% fee on the credits you bought. Top up $10 and you pay $0.80 in fees (the minimum), which covers about six months of this workload.

At this scale, cost isn't the deciding factor. Data rules and setup time are. The math changes at volume: on Gemini 3.1 Pro Preview, 100 million input tokens and 20 million output a month comes to $200 + $240 = $440, and OpenRouter's card fee would add around $24 on top.

Which one should you use?

Start with Google AI Studio if you're building alone, testing prompts, or shipping a small app that only needs Gemini. Turn on billing the moment real user data is involved, mostly for the data terms.

Move to the Gemini Enterprise Agent Platform when the question stops being "does this work?" and becomes "who approved this?" If your company runs on Google Cloud and needs IAM, audit logs and one invoice, it's the right home. The shared SDK keeps the move cheap.

Use OpenRouter if Gemini is one of several models you call. Comparing Gemini against Claude and GPT on the same prompts, or failing over when a provider has an outage, is exactly what it's for. Paying 5.5% to avoid managing five billing accounts is a fair trade.

My own default for a new project: prototype in AI Studio, route through OpenRouter while you're still deciding which model wins, then go direct to Google once you've committed to Gemini and the volume justifies dropping the fee.

Want to skip the cloud entirely? Our Ollama vs LM Studio vs GPT4All comparison covers running models locally. For coding agents that sit on top of these APIs, see Codex CLI vs Claude Code vs OpenCode, and for the wider stack, our full list of AI tools for developers.

FAQ

What is the difference between Google AI Studio and Vertex AI?

Google AI Studio gives you the Gemini Developer API with a simple API key and a free tier. Vertex AI, renamed the Gemini Enterprise Agent Platform in April 2026, needs a Google Cloud project and service-account auth, and adds enterprise controls like IAM, org policies and Cloud billing. Google recommends the Developer API for most developers.

Is Google AI Studio free?

The AI Studio web interface is free in all supported regions. The Gemini API also has a free tier on most Flash and Flash-Lite models, but Gemini 3.1 Pro Preview is paid only, and free-tier content may be used to improve Google's products.

Does OpenRouter charge more than Google for Gemini?

Not per token. OpenRouter passes through provider prices without markup. It charges a 5.5% fee (minimum $0.80) when you buy credits by card, so your total spend is slightly higher than going direct.

Can I use the same code for AI Studio and the Gemini Enterprise Agent Platform?

Mostly yes. Both use the google-genai SDK. You change the authentication and project settings, not the core calls. Check regional support if you need a specific location, since some preview APIs only offer a global endpoint.

Is Vertex AI discontinued?

No. Google renamed and expanded it as the Gemini Enterprise Agent Platform at Cloud Next in April 2026. Existing Vertex AI workloads kept running without breaking changes.