# `ALLM.Providers.Support.GeminiHeaders`
[🔗](https://github.com/cykod/ALLM/blob/v0.3.0/lib/allm/providers/support/gemini_headers.ex#L1)

Shared HTTP-header builder for Gemini provider adapters. See spec
§32.1 (bundled adapters) and the Phase 16 design's Decision #2.

Layer B helper. Both the chat adapter (`ALLM.Providers.Gemini`) and the
image adapter (`ALLM.Providers.Gemini.Images`, Phase 16.5) inject the
same `x-goog-api-key` and `content-type: application/json` headers.

Per the Phase 16 design's Decision #2: the API key flows on the
`x-goog-api-key` request header, not the `?key=...` query parameter.
Both forms are documented and equivalent server-side; the header form
keeps the API key out of HTTP access logs and metrics.

Per Decision #3: the same header is also the streaming-endpoint
authentication; `streamGenerateContent?alt=sse` accepts identical
headers — only the URL's `?alt=sse` query param differs.

## Examples

    iex> ALLM.Providers.Support.GeminiHeaders.headers("AIza-test")
    [{"x-goog-api-key", "AIza-test"}, {"content-type", "application/json"}]

# `headers`

```elixir
@spec headers(api_key :: String.t()) :: [{String.t(), String.t()}]
```

Build headers for a JSON-bodied Gemini request. Returns
`[{"x-goog-api-key", api_key}, {"content-type", "application/json"}]`.

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*Consult [api-reference.md](api-reference.md) for complete listing*