Telnyx WhatsApp Business API - Go

Installation

bash
go get github.com/team-telnyx/telnyx-go

Setup

go
import (
	"context"
	"fmt"
	"os"

	"github.com/team-telnyx/telnyx-go"
	"github.com/team-telnyx/telnyx-go/option"
)

client := telnyx.NewClient(option.WithAPIKey(os.Getenv("TELNYX_API_KEY")))

All examples below assume client is already initialized as shown above.

Error Handling

All API calls can fail with network errors, rate limits (429), validation errors (422), or authentication errors (401). Always handle errors in production code:

go
ctx := context.TODO()

response, err := client.Messages.SendWhatsapp(ctx, telnyx.MessageSendWhatsappParams{
	From: telnyx.String("+19452940762"),
	To:   telnyx.String("+18005551234"),
	Type: telnyx.F(telnyx.MessageSendWhatsappParamsTypeWhatsapp),
	WhatsappMessage: telnyx.F(telnyx.MessageSendWhatsappParamsWhatsappMessage{
		Type: telnyx.F("text"),
		Text: telnyx.F(map[string]interface{}{
			"body": "Hello from Telnyx!",
		}),
	}),
})
if err != nil {
	var apiErr *telnyx.Error
	if errors.As(err, &apiErr) {
		fmt.Printf("API error: %d - %s\n", apiErr.StatusCode, apiErr.Message)
	}
	return err
}
fmt.Println(response.Data.ID)

Common error codes: 401 invalid API key, 403 insufficient permissions, 404 resource not found, 422 validation error (check field formats), 429 rate limited (retry with exponential backoff).

WhatsApp-Specific Errors

• 40008 — Meta catch-all error. Check template parameters, phone number formatting, and 24-hour window rules.
• 131047 — Message failed to send during the 24-hour window. The customer hasn't messaged you first (for non-template messages).
• 131026 — Recipient phone number is not a WhatsApp user.
• 132000 — Template parameter count mismatch. Ensure the number of parameters matches the template definition.
• 132015 — Template paused or disabled by Meta due to quality issues.

Important Notes

• Phone numbers must be in E.164 format (e.g., +13125550001). Include the + prefix and country code.
• Template messages can be sent anytime. Free-form (session) messages can only be sent within a 24-hour window after the customer last messaged you.
• Template IDs: You can reference templates by Telnyx UUID (template_id) instead of name + language. When template_id is provided, name and language are resolved automatically.
• Pagination: List endpoints return paginated results. Use the auto-paging iterator: iter.Next() in a loop.

Operational Caveats

• The sending phone number must be registered with a WhatsApp Business Account (WABA) and associated with a messaging profile.
• Templates must be in APPROVED status before they can be used for sending.
• Template names must be lowercase with underscores only (e.g., order_confirmation). No spaces, hyphens, or uppercase.
• When creating templates, provide realistic sample values for body parameters — Meta reviewers check these during approval.
• Category selection matters for billing: AUTHENTICATION templates get special pricing but must contain an OTP. UTILITY is for transactional messages. MARKETING for promotional content.
• Meta may reclassify your template category (e.g., UTILITY to MARKETING) which affects billing.

Reference Use Rules

Do not invent Telnyx parameters, enums, response fields, or webhook fields.

• If the parameter, enum, or response field you need is not shown inline in this skill, read references/api-details.md before writing code.
• Before using any operation in ## Additional Operations, read the optional-parameters section and the response-schemas section.
• Before reading or matching webhook fields beyond the inline examples, read the webhook payload reference.

Core Tasks

Send a WhatsApp template message

Send a pre-approved template message. Templates can be sent anytime — no 24-hour window restriction.

client.Messages.SendWhatsapp() — POST /messages/whatsapp

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | From | string (E.164) | Yes | WhatsApp-enabled phone number in +E.164 format | | To | string (E.164) | Yes | Recipient phone number in +E.164 format | | Type | string | No | Must be WHATSAPP | | WhatsappMessage | object | Yes | WhatsApp message object | | MessagingProfileID | string (UUID) | No | Messaging profile to use | | WebhookURL | string (URL) | No | Callback URL for delivery status updates |

go
// Send by template name + language
ctx := context.TODO()

response, err := client.Messages.SendWhatsapp(ctx, telnyx.MessageSendWhatsappParams{
	From: telnyx.String("+19452940762"),
	To:   telnyx.String("+18005551234"),
	Type: telnyx.F(telnyx.MessageSendWhatsappParamsTypeWhatsapp),
	WhatsappMessage: telnyx.F(telnyx.MessageSendWhatsappParamsWhatsappMessage{
		Type: telnyx.F("template"),
		Template: telnyx.F(telnyx.MessageSendWhatsappParamsWhatsappMessageTemplate{
			Name:     telnyx.String("order_confirmation"),
			Language: telnyx.F(telnyx.MessageSendWhatsappParamsWhatsappMessageTemplateLanguage{
				Code: telnyx.String("en_US"),
			}),
			Components: telnyx.F([]telnyx.MessageSendWhatsappParamsWhatsappMessageTemplateComponent{
				{
					Type: telnyx.F("body"),
					Parameters: telnyx.F([]telnyx.MessageSendWhatsappParamsWhatsappMessageTemplateComponentParameter{
						{Type: telnyx.F("text"), Text: telnyx.String("ORD-12345")},
						{Type: telnyx.F("text"), Text: telnyx.String("March 15, 2026")},
					}),
				},
			}),
		}),
	}),
})
if err != nil {
	log.Fatal(err)
}
fmt.Println(response.Data.ID)

go
// Send by Telnyx template_id (no name/language needed)
ctx := context.TODO()

response, err := client.Messages.SendWhatsapp(ctx, telnyx.MessageSendWhatsappParams{
	From: telnyx.String("+19452940762"),
	To:   telnyx.String("+18005551234"),
	Type: telnyx.F(telnyx.MessageSendWhatsappParamsTypeWhatsapp),
	WhatsappMessage: telnyx.F(telnyx.MessageSendWhatsappParamsWhatsappMessage{
		Type: telnyx.F("template"),
		Template: telnyx.F(telnyx.MessageSendWhatsappParamsWhatsappMessageTemplate{
			TemplateID: telnyx.String("019cd44b-3a1c-781b-956e-bd33e9fd2ac6"),
			Components: telnyx.F([]telnyx.MessageSendWhatsappParamsWhatsappMessageTemplateComponent{
				{
					Type: telnyx.F("body"),
					Parameters: telnyx.F([]telnyx.MessageSendWhatsappParamsWhatsappMessageTemplateComponentParameter{
						{Type: telnyx.F("text"), Text: telnyx.String("483291")},
					}),
				},
			}),
		}),
	}),
})
if err != nil {
	log.Fatal(err)
}
fmt.Println(response.Data.ID)

Primary response fields:

• response.Data.ID — Message UUID
• response.Data.To[0].Status — queued, sent, delivered, failed
• response.Data.From.PhoneNumber
• response.Data.Type — WHATSAPP

Send a free-form WhatsApp text message

Send a text message within the 24-hour customer service window.

client.Messages.SendWhatsapp() — POST /messages/whatsapp

go
ctx := context.TODO()

response, err := client.Messages.SendWhatsapp(ctx, telnyx.MessageSendWhatsappParams{
	From: telnyx.String("+19452940762"),
	To:   telnyx.String("+18005551234"),
	Type: telnyx.F(telnyx.MessageSendWhatsappParamsTypeWhatsapp),
	WhatsappMessage: telnyx.F(telnyx.MessageSendWhatsappParamsWhatsappMessage{
		Type: telnyx.F("text"),
		Text: telnyx.F(map[string]interface{}{
			"body": "Your order has shipped!",
		}),
	}),
})
if err != nil {
	log.Fatal(err)
}
fmt.Println(response.Data.ID)

List WhatsApp Business Accounts

client.Whatsapp.BusinessAccounts.List() — GET /v2/whatsapp/business_accounts

go
ctx := context.TODO()

response, err := client.Whatsapp.BusinessAccounts.List(ctx, telnyx.WhatsappBusinessAccountListParams{})
if err != nil {
	log.Fatal(err)
}
for _, waba := range response.Data {
	fmt.Printf("%s: %s (%s)\n", waba.ID, waba.Name, waba.Status)
}

Primary response fields:

• waba.ID — Telnyx WABA UUID
• waba.WabaID — Meta WABA ID
• waba.Name — Business name
• waba.Status — Account status
• waba.Country — WABA country

List templates for a WABA

client.Whatsapp.Templates.List() — GET /v2/whatsapp/message_templates

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | WabaID | string (UUID) | Yes | Telnyx WABA UUID | | Category | string | No | Filter: AUTHENTICATION, MARKETING, UTILITY | | Status | string | No | Filter: APPROVED, PENDING, REJECTED, DISABLED |

go
ctx := context.TODO()

response, err := client.Whatsapp.Templates.List(ctx,
	telnyx.WhatsappTemplateListParams{
		WabaID: telnyx.String("019c1ff0-5c30-7f36-8436-730b1d0b0e56"),
		Status: telnyx.String("APPROVED"),
	},
)
if err != nil {
	log.Fatal(err)
}
for _, tmpl := range response.Data {
	fmt.Printf("%s: %s (%s) - %s\n", tmpl.ID, tmpl.Name, tmpl.Category, tmpl.Status)
}

Primary response fields:

• tmpl.ID — Telnyx template UUID (use as template_id when sending)
• tmpl.Name — Template name
• tmpl.Category — AUTHENTICATION, MARKETING, or UTILITY
• tmpl.Language — Language code
• tmpl.Status — APPROVED, PENDING, REJECTED, DISABLED
• tmpl.Components — Template components

Create a message template

client.Whatsapp.Templates.Create() — POST /v2/whatsapp/message_templates

go
ctx := context.TODO()

response, err := client.Whatsapp.Templates.Create(ctx,
	telnyx.WhatsappTemplateCreateParams{
		WabaID:   telnyx.String("019c1ff0-5c30-7f36-8436-730b1d0b0e56"),
		Name:     telnyx.String("order_shipped"),
		Category: telnyx.String("UTILITY"),
		Language: telnyx.String("en_US"),
		Components: telnyx.F([]telnyx.WhatsappTemplateCreateParamsComponent{
			{
				Type: telnyx.F("BODY"),
				Text: telnyx.String("Your order {{1}} has been shipped and will arrive by {{2}}."),
				Example: telnyx.F(telnyx.WhatsappTemplateCreateParamsComponentExample{
					BodyText: telnyx.F([][]string{{"ORD-12345", "March 20, 2026"}}),
				}),
			},
		}),
	},
)
if err != nil {
	log.Fatal(err)
}
fmt.Printf("Template created: %s (status: %s)\n", response.Data.ID, response.Data.Status)

List phone numbers for a WABA

client.Whatsapp.PhoneNumbers.List() — GET /v2/whatsapp/phone_numbers

go
ctx := context.TODO()

response, err := client.Whatsapp.PhoneNumbers.List(ctx,
	telnyx.WhatsappPhoneNumberListParams{
		WabaID: telnyx.String("019c1ff0-5c30-7f36-8436-730b1d0b0e56"),
	},
)
if err != nil {
	log.Fatal(err)
}
for _, pn := range response.Data {
	fmt.Printf("%s - quality: %s\n", pn.PhoneNumber, pn.QualityRating)
}

Webhook Verification

Telnyx signs webhooks with Ed25519. Always verify signatures in production:

go
import "github.com/team-telnyx/telnyx-go/webhook"

event, err := webhook.ConstructEvent(
	payload,                                 // []byte — raw request body
	request.Header.Get("telnyx-signature-ed25519"),
	request.Header.Get("telnyx-timestamp"),
	telnyxPublicKey,
)
if err != nil {
	log.Printf("Webhook verification failed: %v", err)
	http.Error(w, "Invalid signature", http.StatusForbidden)
	return
}

Webhooks

These webhook payload fields are inline because they are part of the primary integration path.

Message Delivery Update

| Field | Type | Description | |-------|------|-------------| | data.event_type | enum: message.sent, message.finalized | Delivery status event | | data.payload.id | uuid | Message ID | | data.payload.to[0].status | string | queued, sent, delivered, read, failed | | data.payload.template_id | string | Telnyx template UUID (if template message) | | data.payload.template_name | string | Template name (if template message) |

Template Status Change

| Field | Type | Description | |-------|------|-------------| | event_type | string | whatsapp.template.approved, whatsapp.template.rejected, whatsapp.template.disabled | | payload.template_id | string | Telnyx template UUID | | payload.template_name | string | Template name | | payload.status | string | New template status | | payload.reason | string | Rejection/disable reason |

Template Best Practices

• Naming: Use lowercase with underscores. Be descriptive (e.g., appointment_reminder, not msg1).
• Sample values: Provide realistic examples in the example field — Meta reviewers check these.
• Category selection:
• AUTHENTICATION — OTP/verification codes only. Gets special pricing.
• UTILITY — Transactional (order updates, shipping, account alerts).
• MARKETING — Promotional content, offers, newsletters.
• Keep it concise: Meta prefers shorter templates. Avoid unnecessary formatting.
• Parameters: Use {{1}}, {{2}}, etc. for variable content. Always provide the correct number of parameters when sending.

Important Supporting Operations

| Operation | SDK Method | Use Case | |-----------|-----------|----------| | Get template details | client.WhatsappMessageTemplates.Retrieve() | Check template status | | Get business profile | client.Whatsapp.PhoneNumbers.Profile.Retrieve() | View business profile | | Configure webhooks | client.Whatsapp.BusinessAccounts.Settings.Update() | Subscribe to events |

Additional Operations

| Operation | SDK Method | Endpoint | Required Params | |-----------|-----------|----------|-----------------| | Send WhatsApp message | client.Messages.SendWhatsapp() | POST /messages/whatsapp | From, To, WhatsappMessage | | List WABAs | client.Whatsapp.BusinessAccounts.List() | GET /v2/whatsapp/business_accounts | — | | Get WABA | client.Whatsapp.BusinessAccounts.Retrieve() | GET /v2/whatsapp/business_accounts/:id | WabaID | | List templates | client.Whatsapp.Templates.List() | GET /v2/whatsapp/message_templates | WabaID | | Get template | client.WhatsappMessageTemplates.Retrieve() | GET /v2/whatsapp_message_templates/:id | TemplateID | | Create template | client.Whatsapp.Templates.Create() | POST /v2/whatsapp/message_templates | WabaID, Name, Category, Language, Components | | List phone numbers | client.Whatsapp.PhoneNumbers.List() | GET /v2/whatsapp/phone_numbers | WabaID | | Configure webhooks | client.Whatsapp.BusinessAccounts.Settings.Update() | PATCH /v2/whatsapp/business_accounts/:id/settings | WabaID |