Courier Go SDK

The Courier Go SDK gives typed access to the from Go. It uses strongly typed request structs with omitzero semantics and returns parsed response types. Available on GitHub and pkg.go.dev.

Installation

import (
	"github.com/trycourier/courier-go/v4" // imported as courier
)

Or pin a specific version:

go get -u 'github.com/trycourier/courier-go/v4'

Requires Go 1.22+.

Quick start

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/trycourier/courier-go/v4"
	"github.com/trycourier/courier-go/v4/option"
	"github.com/trycourier/courier-go/v4/shared"
)

func main() {
	client := courier.NewClient(
		option.WithAPIKey(os.Getenv("COURIER_API_KEY")),
	)
	response, err := client.Send.Message(context.TODO(), courier.SendMessageParams{
		Message: courier.SendMessageParamsMessage{
			To: courier.SendMessageParamsMessageToUnion{
				OfUserRecipient: &shared.UserRecipientParam{
					UserID: courier.String("your_user_id"),
				},
			},
			Template: courier.String("your_template_id"),
			Data: map[string]any{
				"foo": "bar",
			},
		},
	})
	if err != nil {
		panic(err.Error())
	}
	fmt.Printf("%+v\n", response.RequestID)
}

The client reads COURIER_API_KEY from your environment. Pass it explicitly with option.WithAPIKey("YOUR_COURIER_API_KEY").

Authentication

Get your API key from in the Courier dashboard. Set it as an environment variable:

export COURIER_API_KEY="YOUR_COURIER_API_KEY"

The SDK reads it by default. To pass the key explicitly:

client := courier.NewClient(
	option.WithAPIKey("YOUR_COURIER_API_KEY"),
)

Sending notifications

Design your notification in , then reference it by ID:

response, err := client.Send.Message(context.TODO(), courier.SendMessageParams{
	Message: courier.SendMessageParamsMessage{
		To: courier.SendMessageParamsMessageToUnion{
			OfUserRecipient: &shared.UserRecipientParam{
				UserID: courier.String("user_123"),
			},
		},
		Template: courier.String("my-template-id"),
		Data: map[string]any{
			"order_id": "10042",
		},
	},
})

Available resources

The SDK covers the full Courier API. Every method is typed and carries Go docstrings.

Resource	Namespace	Description
Send	`client.Send`	Send messages to one or more recipients
Messages	`client.Messages`	Retrieve status, history, and content of sent messages
Profiles	`client.Profiles`	Create, update, and retrieve user profiles
Users	`client.Users`	Manage preferences, tenants, and push tokens per user
Auth	`client.Auth`	Issue JWT tokens for client-side SDK authentication
Lists	`client.Lists`	Manage subscription lists and their subscribers
Audiences	`client.Audiences`	Define and query audience segments
Tenants	`client.Tenants`	Manage tenants for multi-tenant setups
Journeys	`client.Journeys`	Invoke and cancel runs. Create, list, publish, and archive
Brands	`client.Brands`	Manage brand settings (logos, colors, templates)
Notifications	`client.Notifications`	List and inspect notification templates
Translations	`client.Translations`	Workspace `.po` strings for the `{{t}}` helper

Common operations

Checking message status

message, err := client.Messages.Get(context.TODO(), "your-message-id")
fmt.Println(message.Status)
fmt.Println(message.Delivered) // Unix ms timestamp; 0 until delivered

Managing user profiles

_, err := client.Profiles.New(context.TODO(), "user_123", courier.ProfileNewParams{
	Profile: map[string]any{
		"email": "sarah@acme-corp.com",
		"name":  "Sarah Bennett",
	},
})

profile, err := client.Profiles.Get(context.TODO(), "user_123")

Issuing JWT tokens

Courier’s (React, JavaScript, mobile) authenticate users with a JWT your backend issues. covers the token flow, the scope strings, and token refresh. Use client.Auth.IssueToken:

result, err := client.Auth.IssueToken(context.TODO(), courier.AuthIssueTokenParams{
	Scope:     "user_id:user_123 inbox:read:messages inbox:write:events",
	ExpiresIn: "2 days",
})
fmt.Println(result.Token)

Scope	Permission
`user_id:<id>`	Which user the token is for (required)
`inbox:read:messages`	Read inbox messages
`inbox:write:events`	Mark messages as read/archived
`read:preferences`	Read notification preferences
`write:preferences`	Update notification preferences
`write:user-tokens`	Register push notification tokens

Configuration

Error handling

When the API returns a non-success status code, the SDK returns an error that can be unwrapped to access status and details:

response, err := client.Send.Message(context.TODO(), params)
if err != nil {
	var apiErr *courier.Error
	if errors.As(err, &apiErr) {
		fmt.Println(apiErr.StatusCode)
		fmt.Println(apiErr.Error())
	}
}

Retries

The SDK retries failed requests up to 2 times with exponential backoff. Configure globally or per-request:

client := courier.NewClient(
	option.WithMaxRetries(0), // disable retries
)

Timeouts

The SDK sets no request timeout by default. Add one with a context deadline (or the option.WithRequestTimeout client option):

ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
defer cancel()

response, err := client.Send.Message(ctx, params)

Journeys

are multi-step workflows: send, delay, branch, throttle, digest, and more. Invoke one by ID or alias to start a run. Cancel runs by ID, or by a shared cancelation token.

// Start a run (by journey ID or alias); the response includes a RunID
response, err := client.Journeys.Invoke(context.TODO(), "your-journey-id", courier.JourneyInvokeParams{
    JourneysInvokeRequest: courier.JourneysInvokeRequestParam{
        UserID: courier.String("user_123"),
        Data:   map[string]any{"order_id": "A-1042"},
    },
})

// Cancel one run, or every run sharing a cancelation token
_, err = client.Journeys.Cancel(context.TODO(), courier.JourneyCancelParams{
    CancelJourneyRequest: courier.CancelJourneyRequestParamOfByRunID(response.RunID),
})

cancel takes exactly one of run_id or cancelation_token (spelled with one “l”). Build and manage journeys from code with create, list, publish, and archive. See .

More operations

A few more resources from the full :

Resource	Method	Use case
User preferences	`client.Users.Preferences.Get(ctx, userId, courier.UserPreferenceGetParams{})`	Fetch a user’s notification preferences for your
Cancel a message	`client.Messages.Cancel(ctx, messageId)`	Cancel a delayed or queued message before delivery
Push tokens	`client.Users.Tokens.AddSingle(ctx, token, params)`	Register a device push token for , , , or

API Reference

Full REST API docs with request/response examples.

Send API

Learn about the Send endpoint, routing, and message options.

Quickstart

Send your first notification in under two minutes.

GitHub

Source code, issues, and changelog.

Idempotent sends

Pass an idempotency key and Courier replays the first response for that key instead of sending again. The SDK sets the Idempotency-Key header for you. covers the scoping rule and the replay window.

response, err := client.Send.Message(context.TODO(), courier.SendMessageParams{
	Message: courier.SendMessageParamsMessage{
		To: courier.SendMessageParamsMessageToUnion{
			OfUserRecipient: &shared.UserRecipientParam{UserID: courier.String("user_123")},
		},
		Template: courier.String("nt_01kx4h2jdafq8bk9aftxak4b40"),
	},
	IdempotencyKey: courier.String("6f3b8c2a-9d4e-4b7a-a1c5-2e8f0d5b7a91"),
})

Get started

Server

Client

Installation

Quick start

Authentication

Sending notifications

Available resources

Common operations

Checking message status

Managing user profiles

Issuing JWT tokens

Configuration

Error handling

Retries

Timeouts

Journeys

More operations

API Reference

Send API

Quickstart

GitHub

Idempotent sends

​Installation

​Quick start

​Authentication

​Sending notifications

​Available resources

​Common operations

​Checking message status

​Managing user profiles

​Issuing JWT tokens

​Configuration

​Error handling

​Retries

​Timeouts

​Journeys

​More operations

API Reference

Send API

Quickstart

GitHub

​Idempotent sends

Installation

Quick start

Authentication

Sending notifications

Available resources

Common operations

Checking message status

Managing user profiles

Issuing JWT tokens

Configuration

Error handling

Retries

Timeouts

Journeys

More operations

Idempotent sends