Head to head · LLM inference · October 2026 research run

Azure OpenAI in Foundry Models vs Vertex AI (Gemini Enterprise Agent Platform)

Vertex AI (Gemini Enterprise Agent Platform) scores 88.7 (AA) on agent readiness against Azure OpenAI in Foundry Models's 80 (A), and leads in 6 of 7 scored categories. Both do llm inference.

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Which one, for what

Azure OpenAI in Foundry Models A

Best for Teams on Azure that need OpenAI models with Entra ID, private networking, EU or US data zones or FedRAMP scope, and one resource that also serves DeepSeek, Llama, Mistral and Grok models.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

Intermittent failures and 5xx errors in Sweden Central for about six hours on 29 September 2026

Vertex AI (Gemini Enterprise Agent Platform) AA

Best for Google Cloud customers who need Gemini with residency, VPC-SC, provisioned throughput and an SLA, or Claude under a Google bill.

Ahead on

  • Reliability, 99 against 80
  • Schema & documentation, 94 against 87
  • Payments & pricing, 40 against 20
  • Maintenance & community, 91 against 86
  • Transparency & trust, 90 against 83

Also in its favour

  • Free to start without a card

Watch for

The SLA drops from 99.5 to 95 per cent for short-term availability models, Gemini 3.7 and 3.6 Flash among them

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Payments & pricing Vertex AI (Gemini Enterprise Agent Platform) +20

Azure OpenAI in Foundry Models 20

No x402, MPP or L402 (0). Per-1M-token prices are public in the Azure Retail Prices API without a login, while the pricing page fills its table with JavaScript and showed GPT-6 prices as pending on 6 October (20). The quota tiers include a Free tier, but an Azure subscription needs a payment method (0). A person signs up for Azure in a browser and creates a resource and a deployment before the first call (0).

Vertex AI (Gemini Enterprise Agent Platform) 40

No x402, MPP or L402 (0). Per-token prices per model and option published without a login (20). Express mode gives new Google Cloud users 90 days free within quotas with no billing details, though it's in Preview and needs a @gmail.com account (20). A person signs up in the console to get the express key (0).

Reliability Vertex AI (Gemini Enterprise Agent Platform) +19

Azure OpenAI in Foundry Models 80

Azure status page with post-incident reviews, listing Azure OpenAI Service, Foundry Models and Foundry Agent Service as components (20). One incident in the 90 days to 6 November 2026 names Azure OpenAI, and no review after it does, intermittent request failures, higher latency and HTTP 5xx errors in Sweden Central from 10:03 to 15:58 UTC on 29 September 2026 (tracking 7QL5-Z50), counted as one major outage as in the Foundry fine-tuning dossier. The 23 July West US review and the 30 September gateway incident don't name it (10). Quota tiers from Free to Tier 6 with TPM and RPM per model and deployment type, 1,000 RPM and 1,000,000 TPM for each GPT-6 model on Global Standard at Tier 1 (15). 429 responses carry retry-after-ms, every response carries x-ratelimit-* headers, and the quota guide gives exponential backoff with jitter and SDK retry settings (15). The models page says models sold by Azure are covered by Azure service-level agreements and links the Online Services SLA. The consolidated SLA document wouldn't download on 6 October and wasn't retried on 6 November, so the clause rests on Microsoft's docs, read the same way as the 5 October Azure Speech check (10). The v1 API is GA and the GPT-6 models carry no preview label (10).

Vertex AI (Gemini Enterprise Agent Platform) 99

Google Cloud status dashboard with per-product history (20). Its incident feed, read on 6 November, has no incident naming Vertex Gemini API, Gemini or the Agent Platform in the 90 days. The regional incidents of 20 August, 1 September and 20 October (europe-west2) and the Cloud Storage incident of 8 and 9 October didn't list it among affected products (30). Standard PayGo publishes usage tiers by 30-day spend with baseline throughput, 2,000,000 to 50,000,000 tokens a minute for Flash models and 500,000 to 10,000,000 for Pro, plus quota tables for other methods (15). A 429 page says to use the global endpoint and truncated exponential backoff, and a retry-strategy page (15). SLA of 99.5 per cent a month on generateContent and streamGenerateContent, 95 per cent for short-term availability models, and a latency SLO on Provisioned Throughput. The 429 page says pay-as-you-go 429s don't count toward the SLA error rate (10). Gemini 4 Argon reached GA on 13 October and Gemini 3.8 Flash moved to the 12-month tier, and the v1 API, 3.5 Flash-Lite and Claude Opus 5.5 are GA, but express mode was Preview at the 6 October check (9 of 10, up from 8). Up from 98 on 6 October.

Schema & documentation Vertex AI (Gemini Enterprise Agent Platform) +7

Azure OpenAI in Foundry Models 87

OpenAPI 3.2 spec for the v1 data plane in Azure/azure-rest-api-specs (azure-v1-v1-generated.json, 71 paths and 852 schemas), linked from the v1 API page (25). No llms.txt at learn.microsoft.com (404). Learn pages offer Copy Markdown and the Markdown sources are public in MicrosoftDocs/azure-ai-docs, last merged 5 October (5 of 10). The models page lists each model's capabilities, context and API support, but the model choice guide, dated 19 May 2026, doesn't cover GPT-6 (15 of 20). Structured outputs with strict: true on schemas and function tools, though not together with parallel function calls (15). Examples in Python, C#, JavaScript, Go, Java and REST, and an error table on the quotas page with a fix for 429 and other codes (15). The v1 path replaces monthly api-version values, with preview capabilities opted into by header, a dated API version changelog and dated model versions. On 6 November the Foundry what's new still covered August, though updated on 5 November, and no Azure OpenAI what's new was found at learn.microsoft.com/en-us/azure/foundry/openai/whats-new, which answered 404 (12 of 15).

Vertex AI (Gemini Enterprise Agent Platform) 94

Model reading. Keyless discovery document for the Agent Platform API v1, revision 20260930, with 1,128 methods and 1,493 schemas (25). No llms.txt, but every docs page answers as Markdown at .md.txt, counted as for vertex-ai-tuning (10). Model cards give limits, capabilities and retirement dates, and the 3.8 Flash card says when to use 3.7 Flash instead, but the docs mix the Vertex AI and Agent Platform names, and the OpenAI page tells new users to call the Gemini Developer API instead (16 of 20). Structured output with response_schema and response_mime_type: application/json always follows the schema per the docs, and complex schemas fail with a 400 (15). Examples on every page and a 429 guide, but we found no full error code list for generateContent (13 of 15). Versioned v1 and v1beta1 APIs and release notes with entries on most working days, newest 5 November 2026 (15).

Transparency & trust Vertex AI (Gemini Enterprise Agent Platform) +7

Azure OpenAI in Foundry Models 83

Closed service under the Microsoft Product Terms, with the v1 spec under MIT and the OpenAI SDKs under Apache-2.0 (15). The data privacy page agrees with the product terms on no training and states where data is processed and stored by deployment type, but gives no retention period for the human-review store and sits beside a 30-day default for Responses data (24 of 30). A published lifecycle policy and a retirement schedule with dates and replacements, but on 6 November the schedule listed gpt-realtime-mini 2025-10-06 and 2025-12-15 twice each with different retirement dates, and no GPT-6 model yet (18 of 20, down from 20). Data locations stated for Standard, Data Zone and Global deployments, and a public sub-processor list per the 5 October Azure Speech check, not re-read (20).

Vertex AI (Gemini Enterprise Agent Platform) 90

Closed service under the Google Cloud terms, with the Gen AI SDKs under Apache-2.0 and a public discovery document (18, as for Bedrock's open service models). The zero data retention and abuse monitoring pages agree with the Cloud terms and give periods for each case, 24 hours in memory, up to 90 days for flagged prompts, 30 days for Advanced AI models, 3 days for Search grounding logs and 30 days for Maps grounding, and say which can't be switched off (27 of 30). A dated model versions table with release and retirement dates and a stated 12-month or 45-day policy, but on 6 November it still listed Gemini 2.5 Pro, Flash and Flash-Lite as available with a 20 October 2026 retirement date and left them out of the retired table (18 of 20, down from 20). The Cloud subprocessor list with locations, per the 1 October vertex-ai-tuning check, regional and multi-region endpoints, and per-model ML processing locations on the partner model cards (20).

Maintenance & community Vertex AI (Gemini Enterprise Agent Platform) +5

Azure OpenAI in Foundry Models 86

Model reading. GPT-6.1 Terra released on Azure on 26 October 2026 and a gpt-chat-latest preview of 7 October was added, after GPT-6.1 Sol on 29 September (30). GA models get a retirement date 18 months after launch, set at release and readable through the Models API, with at least 60 days' email and Service Health notice, and previews at least 30 days, so a GA retirement is known more than six months ahead (12 of 12). Many shutdown dates in the 90 days to 6 November, most of them previews or partner models, among them DeepSeek-R1 (13 August), MAI-Image-2 and 2e (15 August), model-router previews (30 August), MAI-Transcribe-1 (15 September), MAI-Image-2.5 previews (1 October), the 2025-03-20 audio models and sora-2 (15 October), a Cohere Command A Plus preview (16 October) and gpt-image-1 (23 October), each in the schedule with a replacement where one exists (4 of 8). The Foundry what's new page, still on August when read on 6 November, plus Microsoft Q&A and paid support; no Azure OpenAI what's new was found (10 of 15). The SDKs are OpenAI's repositories, replies not sampled (5 of 10). Current official SDKs, openai 3.46.0 on PyPI (5 November) and 7.53.0 on npm, plus Microsoft's @azure/openai 2.0.0 companion (15). Supported runtimes stated, Python 3.9 or later and Node.js 20 or later, though openai 3.46.0 requires Python 3.10 (10).

Vertex AI (Gemini Enterprise Agent Platform) 91

Model reading. Gemini Omni 1.2 Flash GA on 5 November, Grok 4.7 GA on 27 October, Gemini 4 Argon GA on 13 October and Claude Haiku 5.5 on 7 October 2026 (30). Stable models stay at least 12 months, and since 6 October Gemini 4 Argon and Gemini 3.8 Flash are in that tier, while 3.7 and 3.6 Flash remain short-term with at least 45 days' notice once a date is set (10 of 12, up from 8). Gemini 2.5 Pro, Flash and Flash-Lite were due to retire on 20 October, three models on one date after more than 12 months, with replacements named. We didn't check partner model retirements (6 of 8, down from 8). Dated release notes on most working days, newest 5 November, and Cloud Customer Care (15). python-genai replies not sampled this run (5 of 10). Current SDKs, google-genai 3.0.0 on 6 November and @google/genai 3.0.0, and google-cloud-aiplatform 2.7.0 on 28 October 2026 (15). Supported runtimes stated, Python 3.10 or later and Node 20 or later, per the 6 October check (10). Unchanged at 91.

Score by category

CategoryWeight this runAzure OpenAI in Foundry ModelsVertex AI (Gemini Enterprise Agent Platform)Edge
Reliability16%208099Vertex AI (Gemini Enterprise Agent Platform) +19
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28794Vertex AI (Gemini Enterprise Agent Platform) +7
Agent ergonomics13%16.29897Azure OpenAI in Foundry Models +1
Security & auth14%17.59597Vertex AI (Gemini Enterprise Agent Platform) +2
Payments & pricing10%12.52040Vertex AI (Gemini Enterprise Agent Platform) +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88691Vertex AI (Gemini Enterprise Agent Platform) +5
Transparency & trust7%8.88390Vertex AI (Gemini Enterprise Agent Platform) +7
Negative events≤1500
TotalA 80/100AA 88.7/100

Facts side by side

FactAzure OpenAI in Foundry ModelsVertex AI (Gemini Enterprise Agent Platform)
KindModel APIModel API
VendorMicrosoftGoogle Cloud
Hosted endpointhttps://<resource>.openai.azure.com/openai/v1https://aiplatform.googleapis.com/v1
TransportsHTTPHTTP
AuthOAuth or keyOAuth or key
PricingPay per usePay per use
x402nono
LicenceProprietary service under the Microsoft Product Terms. The v1 OpenAPI spec is MIT, and the OpenAI SDKs the docs use are Apache-2.0Proprietary service under the Google Cloud Platform terms. Partner models carry their providers' terms. The Google Gen AI SDKs are Apache-2.0
Read-only variant documentednono
llms.txtnono
Last release2026-10-262026-11-05
Terms last updatedno date given2026-09-02
Privacy policy last updated2026-09-012026-10-01
Customer content may train modelsyesyes
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waivernot found in the textnot found in the text
Popularity454k npm/wk20.9M PyPI/wk

What the same task costs

TaskAzure OpenAI in Foundry ModelsVertex AI (Gemini Enterprise Agent Platform)
Research a product and write a sourced reportgpt-6-astra on Azure OpenAI in Foundry Models, gemini-3.1-pro-preview on Vertex AI (Gemini Enterprise Agent Platform)$110$22.03
Build a small four-page websitegpt-6-astra on Azure OpenAI in Foundry Models, gemini-3.1-pro-preview on Vertex AI (Gemini Enterprise Agent Platform)$25.07$5.09
Find and fix a bug in a large codebasegpt-6-astra on Azure OpenAI in Foundry Models, gemini-3.1-pro-preview on Vertex AI (Gemini Enterprise Agent Platform)$5.41$1.09

Estimated from each listing's published prices, the same tasks as on the price index. Plans, minimums and free allowances aren't counted.

Verdicts

Azure OpenAI in Foundry Models

An OpenAI-compatible v1 API with a public OpenAPI spec, Entra ID roles in place of shared keys and FedRAMP High scope, with GPT-6 and GPT-6.1 at OpenAI's list prices on Global Standard. Access needs an Azure subscription with a card and a deployment per model, and a 29 September 2026 incident caused about six hours of failures in Sweden Central.

Vertex AI (Gemini Enterprise Agent Platform)

Gemini, Claude and open models through one Google Cloud API with IAM, regional endpoints, schema-guaranteed JSON and a 99.5 per cent SLA, and no Vertex incident on the Cloud status page in the 90 days to 6 November 2026. Gemini 4 Argon and 3.8 Flash have 12-month availability, but short-term Flash models get a 95 per cent SLA.

Before you call either

Azure OpenAI in Foundry Models

  1. Point the OpenAI SDK at https://<resource>.openai.azure.com/openai/v1/ and pass the deployment name as model, not the model id
  2. Prefer Entra ID with the Cognitive Services OpenAI User role over the resource key, which opens the whole data plane
  3. On 429 wait for retry-after-ms, then back off with jitter. The OpenAI SDK retries twice by default
  4. Set store: false on Responses calls you don't need kept. Stored responses persist 30 days by default
  5. Keep remote MCP approvals on for servers you don't control. They're required by default

Vertex AI (Gemini Enterprise Agent Platform)

  1. Call the global location on aiplatform.googleapis.com unless data residency requires a Region. The 429 guide says it spreads load and reduces errors
  2. Back off exponentially on 429 Resource exhausted. On Standard PayGo it means shared capacity is busy, not a fixed quota
  3. Send response_schema with response_mime_type: application/json. JSON mode alone doesn't guarantee valid output
  4. Set store to false on Interactions API calls. It defaults to true and keeps prompts and responses
  5. Pin gemini-4-argon or gemini-3.8-flash, both in the 12-month tier, rather than 3.7 or 3.6 Flash, which retire on 28 January 2027 and 19 November 2026

Questions

Which is better for AI agents, Azure OpenAI in Foundry Models or Vertex AI (Gemini Enterprise Agent Platform)?

Vertex AI (Gemini Enterprise Agent Platform) scores 88.7 (AA) on agent readiness against Azure OpenAI in Foundry Models's 80 (A), and leads in 6 of 7 scored categories.

Do Azure OpenAI in Foundry Models and Vertex AI (Gemini Enterprise Agent Platform) need an API key?

Both take an API key or an OAuth sign-in.

Can an agent call Azure OpenAI in Foundry Models and Vertex AI (Gemini Enterprise Agent Platform) without installing anything?

Yes. Azure OpenAI in Foundry Models has a hosted endpoint at https://<resource>.openai.azure.com/openai/v1 and Vertex AI (Gemini Enterprise Agent Platform) at https://aiplatform.googleapis.com/v1.

Other comparisons with Azure OpenAI in Foundry Models or Vertex AI (Gemini Enterprise Agent Platform)

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