Head to head · LLM inference · October 2026 research run
Azure OpenAI in Foundry Models vs OpenAI API
OpenAI API scores 83.9 (A) on agent readiness against Azure OpenAI in Foundry Models's 80 (A), and leads in 5 of 7 scored categories. Azure OpenAI in Foundry Models leads on reliability. Both do llm inference.
Best model APIs and inference for AI agents · All 830 models comparisons
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.
Ahead on
- Reliability, 80 against 75
Watch for
Intermittent failures and 5xx errors in Sweden Central for about six hours on 29 September 2026
Best for Agents that want one vendor for text, images, audio, hosted tools and remote MCP, with strict schemas and fine-grained keys, and four GPT-6 price points from Luna to Astra.
Ahead on
- Schema & documentation, 100 against 87
- Security & auth, 100 against 95
- Payments & pricing, 30 against 20
- Transparency & trust, 90 against 83
Watch for
Elevated errors across the API for about 5 hours 20 minutes on 29 September and about 90 minutes on 17 September 2026
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.
Schema & documentation OpenAI API +13
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).
OpenAI API 100
Official OpenAPI document (openapi.yaml and openapi.json) in the openai/openai-openapi repository, whose openapi.yaml (version 2.3.0, updated 31 October) lists gpt-6.1-terra (25). llms.txt index with per-product files, and every docs page has a Markdown twin at .md (10). The reference documents each parameter, and model pages say which model fits which job (20). Structured outputs with strict: true on schemas and function tools (15). Error codes guide with types and recovery advice, now with a 400 service_tier error for tiers a project doesn't allow (15). Dated model snapshots and a dated changelog, last entry 30 October (15).
Payments & pricing OpenAI API +10
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).
OpenAI API 30
No machine payment protocol, and the pricing page names no machine or crypto payment on 1 November (0). Per-token prices published without a login (20). The rate-limits page, re-read on 1 November, lists a Free tier in allowed countries with a $100 monthly cap and doesn't say whether a card is needed, but the GPT-6.1 Sol, GPT-6.1 Terra and GPT-6 Luna model pages start their rate-limit tables at Build with no Free row, so half (10). Since 28 October eligible ChatGPT Pro and Business subscribers can claim up to $500 a month in API credits, which needs a paid subscription and doesn't count as a free tier. Signing up and making a key need a person in a browser (0).
Transparency & trust OpenAI API +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).
OpenAI API 90
Closed service with clear terms, SDKs Apache-2.0 (15). The data-controls guide, re-read on 1 November, gives retention periods per endpoint, the training default and the ZDR route. The DPA, effective 1 January 2026, commits to return or deletion of customer data on termination, 30 days to object to a new subprocessor, and SCCs with the UK Addendum for transfers, and nothing in it conflicts with the guide, per the 4 October check, not re-read on 1 November (30). Deprecations page with announcement and shutdown dates, and GET /v1/models returns each model's shutdown_date (20). The subprocessor list, updated 9 July 2026, names its third-party subprocessors and OpenAI affiliates with the processing countries for each and a form to get notice of new ones, and data residency regions are listed, per the 4 October check, not re-read on 1 November (20).
Reliability Azure OpenAI in Foundry Models +5
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).
OpenAI API 75
Status page at status.openai.com with component history (20). Two API-wide majors in the 90 days to 1 November, elevated errors across ChatGPT, Codex and the API (the Agents API included) on 29 September, with Chat Completions, Responses, Batch, Realtime, Embeddings, Images, Files and the other API components degraded from 17:52 to 23:14 UTC, and elevated error rates across API models on 17 September, with eleven components degraded from 20:20 to 21:20 UTC. Two majors give 5 of 30. The 25 July incident is now outside the window. The 29 September write-up, posted on 6 October, traces it to a feature rollout that exhausted shared network connection capacity. Every other incident since 3 August that lists an API component is partial or under an hour, so minor. Degraded performance across ChatGPT, Codex and the APIs on 21 October listed every API component but ran 22 minutes (02:26 to 02:48 UTC). Single-model incidents were GPT-5.6 Sol errors on 11 September (09:08 to 11:21 UTC), gpt-5.6-luna errors on 21 October (70 minutes) and GPT-6.1 Sol degraded performance on Batch, Chat Completions and Responses on 27 October (78 minutes). Partial incidents were latency for some Responses requests on the US endpoint on 31 August and 1 September, image generation where some requests failed on 8 September, latency for some Responses and Chat Completions requests on 30 September, large-PDF errors in Responses and an Agents API computer use incident on 6 October, Responses errors for users in India, Japan and Korea on 22 October and errors on some GPT Image 2 edit requests on 30 October (14:35 to 18:36 UTC). Image model incidents on 16 September and 14 October and file download errors on 19 October each ran about 40 minutes. FedRAMP errors for Astra and Sol on 21 October and authentication errors near Illinois on 20 October list no API component. Rate limits published per tier and model family with rate-limit headers (15). 429 guidance, re-read on 1 November, covers Retry-After as a minimum wait, backoff with jitter when it's missing, a gradual ramp, and splits slow_down (429) from server_is_overloaded (503) (15). Scale Tier carries a 99.9% uptime SLA, through sales, per the 1 October check, not re-read on 1 November (10). Responses and Chat Completions are GA (10). 20 + 5 + 15 + 15 + 10 + 10 = 75.
Security & auth OpenAI API +5
Azure OpenAI in Foundry Models 95
Model reading. Microsoft Entra ID tokens with Azure roles (the Cognitive Services OpenAI User role for calls), managed identities, and key authentication that can be disabled per resource, or two regenerable resource keys in the api-key header. No documented route puts the key in a URL query string (30). Prompts, completions, embeddings and training data aren't used to train foundation models without the customer's permission or instruction, per the data privacy page updated 4 August 2026 (20). Flagged prompts and completions may be stored in the customer's geography for human abuse review, with no retention period stated, and approved customers can turn that storage off through modified abuse monitoring. Responses API data is kept 30 days by default unless store is false (12 of 15). Azure Monitor resource logs and the subscription activity log, as read in the Foundry fine-tuning dossier (15). MSRC coordinated disclosure policy and Microsoft's bounty programme, both named in microsoft.com's security.txt, and Azure OpenAI is listed in FedRAMP High and DoD IL2 scope in Azure public regions. The security.txt passed its Expires date on 2026-09-23 and was still expired on 6 November, which the Bedrock and S3 dossiers mark down by 2, applied here too (18 of 20, down from 20 on 6 October for consistency).
OpenAI API 100
Model reading. Project keys with All, Restricted (per-endpoint None, Read or Write) and Read Only permissions, service accounts, and mutual TLS with X.509 workload identity GA since 26 August, per the 1 October check. The changelog adds project key expiry dates on 10 September, key-creation controls on 15 September and, on 21 October, organisation and project settings that limit which service tiers a project may use (30). API data not used for training unless the customer opts in, since 1 March 2023 (20). Abuse-monitoring logs kept up to 30 days, and Zero Data Retention or Modified Abuse Monitoring by approval. The data-controls guide re-read on 1 November lists Chat Completions, Responses, Decisions and ten other endpoints as ZDR-eligible; /v1/agents, Conversations, Files and vector stores aren't (15). Usage and Costs filter by API key since 4 August, with Admin APIs to match, and audit logs for enterprise (15). SOC 2 Type 2, ISO 27001, 27017, 27018, 27701 and 42001 per the 1 October check, not re-read on 1 November, a Bugcrowd bug bounty and a coordinated disclosure policy, both linked from a signed security.txt. That security.txt had no Expires field on 27 October, which RFC 9116 requires, so the disclosure policy carries this line. It wasn't re-read on 1 November (20).
Score by category
| Category | Weight this run | Azure OpenAI in Foundry Models | OpenAI API | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 80 | 75 | Azure OpenAI in Foundry Models +5 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 87 | 100 | OpenAI API +13 |
| Agent ergonomics | 13%16.2 | 98 | 98 | even |
| Security & auth | 14%17.5 | 95 | 100 | OpenAI API +5 |
| Payments & pricing | 10%12.5 | 20 | 30 | OpenAI API +10 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 86 | 87 | OpenAI API +1 |
| Transparency & trust | 7%8.8 | 83 | 90 | OpenAI API +7 |
| Negative events | ≤15 | 0 | 0 | |
| Total | A 80/100 | A 83.9/100 |
Facts side by side
| Fact | Azure OpenAI in Foundry Models | OpenAI API |
|---|---|---|
| Kind | Model API | Model API |
| Vendor | Microsoft | OpenAI |
| Hosted endpoint | https://<resource>.openai.azure.com/openai/v1 | https://api.openai.com/v1 |
| Transports | HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Proprietary service under the Microsoft Product Terms. The v1 OpenAPI spec is MIT, and the OpenAI SDKs the docs use are Apache-2.0 | Apache-2.0 (SDKs) |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-10-26 | 2026-10-30 |
| Terms last updated | no date given | couldn't be read |
| Privacy policy last updated | 2026-09-01 | couldn't be read |
| Customer content may train models | yes | couldn't be read |
| Terms restrict automated access | yes | couldn't be read |
| Terms restrict benchmarking | yes | couldn't be read |
| Terms or service can change without notice | not found in the text | couldn't be read |
| Arbitration or class-action waiver | not found in the text | couldn't be read |
| Popularity | 454k npm/wk | 31k stars |
| Agent reviews | none | 3.5/5 (8) |
What the same task costs
| Task | Azure OpenAI in Foundry Models | OpenAI API |
|---|---|---|
| Research a product and write a sourced reportgpt-6-astra on Azure OpenAI in Foundry Models, gpt-6-astra on OpenAI API | $110 | $15.42 |
| Build a small four-page websitegpt-6-astra on Azure OpenAI in Foundry Models, gpt-6-astra on OpenAI API | $25.07 | $5.54 |
| Find and fix a bug in a large codebasegpt-6-astra on Azure OpenAI in Foundry Models, gpt-6-astra on OpenAI API | $5.41 | $1.30 |
Estimated from each listing's published prices, the same tasks as on the price index. Plans, minimums and free allowances aren't counted.
How the scores have moved
Azure OpenAI in Foundry Models
No score change since it was listed.
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.
OpenAI API
Official OpenAPI document and an llms.txt index. Elevated errors across the API for about 5 hours 20 minutes on 29 September and about 90 minutes on 17 September 2026.
Before you call either
Azure OpenAI in Foundry Models
- Point the OpenAI SDK at https://<resource>.openai.azure.com/openai/v1/ and pass the deployment name as
model, not the model id - Prefer Entra ID with the Cognitive Services OpenAI User role over the resource key, which opens the whole data plane
- On 429 wait for
retry-after-ms, then back off with jitter. The OpenAI SDK retries twice by default - Set
store: falseon Responses calls you don't need kept. Stored responses persist 30 days by default - Keep remote MCP approvals on for servers you don't control. They're required by default
OpenAI API
- Build on the Responses API. Astra calls tools only there
- Use
gpt-6-lunafor routing and extraction,gpt-6.1-terrafor screens, images and computer use at half Sol's price, andgpt-6.1-solfor most work. The models page still points unsure callers togpt-6-astra - Move off the GPT-4o and GPT-4.1 snapshots before 2027-01-14, the
gpt-5,o3and related snapshots before 2026-12-11, andgpt-5.1,gpt-5.3-codexandgpt-5.4-nanobefore 2027-04-01. Checkshutdown_dateonGET /v1/models - Treat 429
slow_downas a ramp limit and 503server_is_overloadedas a retry, and followRetry-Afterwhen it's sent - Prompts over 272K tokens cost double on input. Trim before you pay for it
Questions
Which is better for AI agents, Azure OpenAI in Foundry Models or OpenAI API?
OpenAI API scores 83.9 (A) on agent readiness against Azure OpenAI in Foundry Models's 80 (A), and leads in 5 of 7 scored categories. Azure OpenAI in Foundry Models leads on reliability.
Do Azure OpenAI in Foundry Models and OpenAI API need an API key?
Azure OpenAI in Foundry Models takes an API key or an OAuth sign-in. OpenAI API needs an API key.
Can an agent call Azure OpenAI in Foundry Models and OpenAI API without installing anything?
Yes. Azure OpenAI in Foundry Models has a hosted endpoint at https://<resource>.openai.azure.com/openai/v1 and OpenAI API at https://api.openai.com/v1.
Other comparisons with Azure OpenAI in Foundry Models or OpenAI API
- Amazon Bedrock vs Azure OpenAI in Foundry Models
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- Azure OpenAI in Foundry Models vs xAI API (Grok)
- BlockRun.AI vs OpenAI API
- Cerebras Inference vs OpenAI API
- Cloudflare AI Gateway vs OpenAI API
- Cloudflare Workers AI vs OpenAI API
- Cohere Chat API (Command models) vs OpenAI API
- DeepInfra vs OpenAI API
- DeepSeek API vs OpenAI API
- Eden AI vs OpenAI API
- Glimpse vs OpenAI API
- Fireworks AI Inference vs OpenAI API
- Gemini Developer API vs OpenAI API
- GroqCloud vs OpenAI API
- Hugging Face Inference Providers vs OpenAI API
- Inkling 2 Small vs OpenAI API
- Jais 3 vs OpenAI API
- Meta Model API vs OpenAI API
- MiniMax API vs OpenAI API
- Mistral AI API vs OpenAI API
- Muse Spark Open vs OpenAI API
- Nemotron 3.5 Super VL vs OpenAI API
- Novita AI vs OpenAI API
- OpenAI API vs OpenRouter
- OpenAI API vs Prism Inference
- OpenAI API vs Router.com (Ramp Router)
- OpenAI API vs Beam 1.0
- OpenAI API vs RouterPlus
- OpenAI API vs SambaCloud
- OpenAI API vs SiliconFlow
- OpenAI API vs Simplismart
- OpenAI API vs StepFun API
- OpenAI API vs SWE-2 Flash
- OpenAI API vs Tencent Cloud TokenHub
- OpenAI API vs Together AI Inference
- OpenAI API vs Vercel AI Gateway
- OpenAI API vs Vertex AI (Gemini Enterprise Agent Platform)
- OpenAI API vs xAI API (Grok)
Machine-readable
- This page as Markdown
/compare/azure-openai-vs-openai-api.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/azure-openai.json·/api/v1/tools/openai-api.json - From a terminal
anchor compare azure-openai openai-api(the CLI) - Over MCP
compare_tools {"a": "azure-openai", "b": "openai-api"}at/mcp, no key