> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apollodeploy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Send emails with Zig

> Send a transactional email with the official Apollo Signal Zig SDK

The Zig package targets Zig 0.16.0 exactly. Its class-based client uses
`https://api.signal.apollodeploy.com` by default and keeps allocation and I/O ownership explicit.

Before you start, [create an API key](/signal/create-an-api-key) with **Emails: Send** permission
and [verify the From domain](/signal/add-a-domain).

<Steps>
  <Step title="Add the package">
    ```bash theme={"dark"}
    zig fetch --save https://github.com/Apollo-Deploy/signal-sdks/releases/download/v4.0.1/apollo-signal-zig-4.0.1.tar.gz
    ```

    Import the dependency as the `apollo_signal` module in your `build.zig`.
  </Step>

  <Step title="Store your API key">
    Load the key into a trusted server or command-line process. Pass it into the sending function
    instead of embedding it in the binary.
  </Step>

  <Step title="Send an email">
    ```zig theme={"dark"}
    const std = @import("std");
    const signal = @import("apollo_signal");

    pub fn sendEmail(
        allocator: std.mem.Allocator,
        io: std.Io,
        api_key: []const u8,
    ) !void {
        const authorization = try std.fmt.allocPrint(
            allocator,
            "Bearer {s}",
            .{api_key},
        );
        defer allocator.free(authorization);

        const headers = [_]signal.Header{
            .{ .name = "Authorization", .value = authorization },
        };
        var client = signal.Client.init(.{
            .allocator = allocator,
            .io = io,
            .default_headers = &headers,
        });
        defer client.deinit();

        var recipients = [_][]const u8{"alex@example.com"};
        var emails = client.emails();
        var result = try emails.sendEmail(.{
            .from = "auth@mail.company.com",
            .to = &recipients,
            .subject = "Reset your password",
            .text = "Use the secure link in your account to choose a new password.",
        }, .{});
        defer result.deinit();

        switch (result) {
            .success => |email| std.debug.print("{s}\n", .{email.value.id}),
            .api_error => return error.SignalApiError,
        }
    }
    ```
  </Step>
</Steps>

<Note>
  The caller owns the allocator and `std.Io`. Generated results own response memory, so call
  `deinit` exactly once after handling either success or API error metadata.
</Note>

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  </Card>

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