fix(azure): forward realtime_protocol from config and relax api_version check for GA path

[giulio-leone]

Summary

Fixes #22127

Azure's GA v1 realtime API path (/openai/v1/realtime) is unusable when configured via config.yaml because:

1. realtime_protocol set in litellm_params is not reliably forwarded to the handler
2. api_version is unconditionally required, but the GA/v1 path doesn't use it

Changes

1. realtime_api/main.py — Add fallback chain for realtime_protocol

realtime_protocol = (
    kwargs.get("realtime_protocol")
    or litellm_params.get("realtime_protocol")     # NEW: from config.yaml extra fields
    or os.environ.get("LITELLM_AZURE_REALTIME_PROTOCOL")  # NEW: env var fallback
    or "beta"
)

2. llms/azure/realtime/handler.py — Conditional api_version check

# Before: unconditionally required (blocks GA path)
if api_version is None:
    raise ValueError("api_version is required for Azure OpenAI calls")

# After: only required for beta protocol
if api_version is None and realtime_protocol not in ("GA", "V1"):
    raise ValueError("api_version is required for Azure OpenAI calls")

3. Case-insensitive protocol matching

ga, GA, v1, V1 all work correctly now.

4. Type signature fix

_construct_url(api_version: str) → _construct_url(api_version: Optional[str]) since GA path doesn't need it.

Tests

17 tests pass (7 existing + 10 new):

• test_async_realtime_ga_without_api_version — GA path works without api_version
• test_async_realtime_beta_without_api_version_raises — beta still requires api_version
• test_realtime_protocol_env_var_fallback — env var fallback works
• test_realtime_protocol_from_litellm_params — config extra field works
• test_construct_url_case_insensitive_protocol[ga/Ga/gA/V1/v1/GA] — case insensitivity

Backwards Compatible

• Default behavior unchanged (realtime_protocol="beta")
• Existing deployments unaffected

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Project	Deployment	Actions	Updated (UTC)
litellm	Ready	Preview, Comment	Feb 28, 2026 7:16am

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[greptile-apps]

Greptile Summary

This PR fixes Azure's GA (v1) realtime API path by:

• Adding a fallback chain for realtime_protocol (kwargs → litellm_params → env var → "beta") so it can be set via config.yaml
• Relaxing the api_version validation in the handler to allow None when using GA/V1 protocol
• Making protocol matching case-insensitive and updating the type signature accordingly

The handler changes are clean and correct. Two areas need attention:

• The api_version default in main.py (line 131) always resolves to "2024-10-01-preview", so the handler's new GA relaxation is unreachable from the main proxy flow — consider gating the default to beta-only
• Two new tests (test_realtime_protocol_env_var_fallback, test_realtime_protocol_from_litellm_params) duplicate the fallback logic inline instead of actually calling _arealtime, so they don't verify the real function's behavior

Confidence Score: 4/5

• This PR is safe to merge — default behavior is unchanged and GA path is correctly handled at the handler level.
• Core handler changes are well-implemented with case-insensitive matching and proper type signature updates. The api_version default chain in main.py makes the handler relaxation unreachable from the main flow (not a bug but limits the fix's value). Two tests don't exercise the actual function under test. No risk to existing functionality.
• litellm/realtime_api/main.py (api_version default interacts with GA path), tests/test_litellm/llms/azure/realtime/test_azure_realtime_handler.py (two tests don't call _arealtime)

Important Files Changed

Filename	Overview
litellm/llms/azure/realtime/handler.py	Relaxes api_version validation for GA/V1 protocol, adds case-insensitive protocol matching, and updates _construct_url signature to Optional[str]. Changes are clean and correct.
litellm/realtime_api/main.py	Adds litellm_params and env var fallback for realtime_protocol. The api_version default chain always provides a non-None value, making the handler's GA relaxation unreachable from this path.
tests/test_litellm/llms/azure/realtime/test_azure_realtime_handler.py	Good handler-level tests (GA URL, case-insensitivity, beta validation). However, test_realtime_protocol_env_var_fallback and test_realtime_protocol_from_litellm_params don't actually call _arealtime — they duplicate its logic inline, so they don't verify the real function.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["_arealtime() in main.py"] --> B{Resolve realtime_protocol}
    B --> C["kwargs.get('realtime_protocol')"]
    C -->|None| D["litellm_params.get('realtime_protocol')"]
    D -->|None| E["os.environ LITELLM_AZURE_REALTIME_PROTOCOL"]
    E -->|None| F["Default: 'beta'"]
    C -->|found| G[protocol resolved]
    D -->|found| G
    E -->|found| G
    F --> G

    G --> H{Resolve api_version}
    H --> I["api_version or litellm_params.api_version or '2024-10-01-preview'"]
    I --> J["api_version always non-None"]

    J --> K["handler.async_realtime()"]
    K --> L{api_version is None AND protocol not GA/V1?}
    L -->|Yes| M["Raise ValueError"]
    L -->|No| N["_construct_url()"]
    N --> O{protocol.upper in GA, V1?}
    O -->|Yes| P["wss://.../openai/v1/realtime?model=..."]
    O -->|No| Q["wss://.../openai/realtime?api-version=...&deployment=..."]

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_{Last reviewed commit: 994998d}

[greptile-apps]

_{3 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

Tests duplicate logic instead of testing _arealtime

test_realtime_protocol_env_var_fallback imports _arealtime but never calls it. It manually re-implements the fallback chain inline (lines 321-326), so it only proves the Python or chain works — not that _arealtime actually reads LITELLM_AZURE_REALTIME_PROTOCOL. If someone later removes the env var fallback from _arealtime, this test would still pass.

The same issue applies to test_realtime_protocol_from_litellm_params (line 330): it only tests that GenericLiteLLMParams stores extra fields, not that _arealtime consumes realtime_protocol from those params.

Consider making these tests call _arealtime (mocking the Azure handler) and asserting that the handler receives the correct realtime_protocol value.

[greptile-apps]

Additional Comments (1)

litellm/realtime_api/main.py
api_version default makes GA relaxation unreachable here

The api_version fallback chain on lines 128-132 always resolves to a non-None value (defaulting to "2024-10-01-preview"). This means the relaxed api_version is None check added in handler.py:89 will never be triggered from this code path — the handler always receives a valid api_version, even when the GA path doesn't use it.

This isn't a runtime bug (the GA URL is built correctly because _construct_url ignores api_version for GA), but it is misleading: users on the GA path who deliberately omit api_version from their config will silently get "2024-10-01-preview" injected. Consider gating the default to only apply for the beta protocol:

        realtime_protocol = (
            kwargs.get("realtime_protocol")
            or litellm_params.get("realtime_protocol")
            or os.environ.get("LITELLM_AZURE_REALTIME_PROTOCOL")
            or "beta"
        )

        api_version = (
            api_version
            or litellm_params.api_version
            or (None if realtime_protocol.upper() in ("GA", "V1") else "2024-10-01-preview")
        )