Telnyx Email - curl

Installation

# curl is pre-installed on macOS, Linux, and Windows 10+
# jq is required for examples that capture IDs from responses:
#   macOS: brew install jq
#   Debian/Ubuntu: sudo apt-get install jq

Setup

export TELNYX_API_KEY="YOUR_API_KEY_HERE"

All examples below use $TELNYX_API_KEY for authentication.

Error Handling

All API calls can fail with network errors, rate limits (429), validation errors (400 or 422), or authentication errors (401). Preserve the response body so the Telnyx error code and detail remain available:

curl --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": {"email": "sender@example.com", "name": "Example"},
    "to": ["recipient@example.net"],
    "subject": "Hello from Telnyx",
    "text_body": "Your notification is ready."
  }' \
  "https://api.telnyx.com/v2/email_messages"

Common errors: 401 invalid credentials, 403 sender-domain eligibility or verification failure, 404 resource not found, 413 body larger than 8,000,000 bytes, and 422 semantic validation or template-rendering failure. A 429 is not necessarily a transient throughput limit: it can indicate a reputation suspension or a daily policy limit. Inspect .errors[0].code and .errors[0].detail before deciding whether to retry. See the full taxonomy in references/api-details.md.

Important Notes

• Base URL: All paths in this skill are relative to https://api.telnyx.com/v2.
• Sender domain: The domain in from.email must be authorized and ready for sending. A successful create response means accepted, queued, scheduled, or sandbox-created—not delivered.
• Address input: from, reply_to, and each to/cc/bcc item accept either a string address or { "email": "...", "name": "..." }. Recipients must be unique across to, cc, and bcc after case-insensitive normalization.
• Body or template: subject is required unless template_id is supplied. With template_id, do not also send subject, html_body, or text_body; pass Liquid values in template_variables.
• Pagination: Core Email endpoints use page_size (default 25, maximum 100) and the opaque page_cursor returned in .meta.page_cursor. Do not translate these names to page[size] or page[cursor].
• Message listing: GET /email_messages currently implements cursor pagination only; no message filters are exposed. Event and recipient list endpoints have their own filters.

Operational Caveats

• Scheduling is fail-open: scheduled_at is the preferred field. If it is invalid or in the past, the API silently sends immediately. Validate the timestamp before sending and confirm the response status is scheduled when future delivery is required. The legacy send_at alias remains accepted; if both are present, scheduled_at wins.
• Batch status: POST /email_messages/batch always returns 207 Multi-Status, including when every item succeeds. It does not return 202.
• Batch limit: A batch contains 1–50 messages. Split larger jobs and give each request its own idempotency key.
• Idempotency is endpoint-specific: Idempotency-Key is supported only on POST /email_messages, POST /email_messages/batch, POST /email_templates, POST /email_validations, and POST /email_validations/batch. Do not send it universally.
• Sandbox behavior: sandbox_mode: true skips Kafka/MTA delivery, but still persists the message, emits a sandbox event, and creates a non-billable Email Detail Record (EDR). Batch-level sandbox_mode overrides every per-message value.
• 429 requires classification: It can mean reputation suspension or a daily policy limit. Read the error code/detail; do not blindly back off and retry an account-policy failure.
• Attachments are in-band JSON: Put attachment content in the request as a Base64 string. disposition: "inline" plus content_id supports CID references. The whole request body is limited to 8,000,000 bytes (approximately 8 MB), including Base64 overhead.
• Tags are not labels: Outbound tags are immutable billing/reporting attribution propagated to EDRs and Mission Control. Mailbox labels are mutable workflow state and are a different concept.
• Threading is single-send only: in_reply_to_message_id, reply_to_all, and forward_of_message_id are accepted by single send but not by batch send. in_reply_to_message_id and forward_of_message_id are mutually exclusive.

Reference Use Rules

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

• If a parameter, enum, or response field is not shown inline, read references/api-details.md before writing the request or handler.
• Before using an operation in ## Additional Operations, read the parameter reference and the response schemas.
• Before matching webhook fields or event names, read the webhook payload reference. Pollable and subscribable event enums are intentionally different.
• Treat the two delete-message routes marked not yet available as unreachable even though they appear in the OpenAPI contract.

Core Tasks

Send an email

Primary outbound transactional-email flow.

POST /v2/email_messages

Parameter	Type	Required	Description
from	string or email-address object	Yes	Sender address; object form supports email and optional name.
to	array[string or email-address object]	Yes	At least one recipient. Must be unique across all recipient lists.
from_name	string	No	Display name for string from; overrides from.name.
cc	array[string or object]	No	Carbon-copy recipients.
bcc	array[string or object]	No	Blind-copy recipients.
reply_to	string or object	No	Reply-to address; an object name is ignored when stored.
subject	string	Conditional	Required without template_id. Do not use with a template.
html_body	string	No	HTML body. Returned only by the message detail endpoint.
text_body	string	No	Plain-text body. Returned only by the message detail endpoint.
headers	object[string,string]	No	Custom headers; write-only.
attachments	array[attachment]	No	Embedded Base64 attachment objects.
tags	array[string]	No	Immutable EDR/reporting attribution; not returned by the API.
group_id	UUID or null	No	Unsubscribe group for suppression checks.
ignore_suppression	boolean	No	Default false; requires email:override scope and cannot override hard-bounce, complaint, or invalid-address suppressions.
metadata	object	No	Custom write-only metadata.
tracking_settings	object	No	open_tracking and/or click_tracking; omitted values inherit domain settings.
template_id	UUID	No	Liquid template ID. Makes subject/body fields mutually exclusive.
template_variables	object	No	Liquid values; defaults to {}.
scheduled_at	date-time or null	No	Preferred future send time; invalid/past values send immediately.
send_at	date-time	No	Deprecated alias for scheduled_at.
inline_css	boolean	No	Inline CSS before sending; default false.
sandbox_mode	boolean	No	Persist and emit sandbox records without MTA delivery; default false.
in_reply_to_message_id	UUID or null	No	Parent Telnyx message; adds RFC 5322 threading headers.
reply_to_all	boolean or null	No	Reply-all intent; meaningful only with in_reply_to_message_id.
forward_of_message_id	UUID or null	No	Forward provenance; mutually exclusive with in_reply_to_message_id.
Idempotency-Key	header string	No	1–255 letters, digits, _, or -; reuse only for the identical retry.

curl --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 8e03978e-40d5-43e8-bc93-6894a57f9326" \
  -d '{
    "from": {"email": "orders@example.com", "name": "Example Orders"},
    "to": [{"email": "customer@example.net", "name": "Customer"}],
    "subject": "Order received",
    "html_body": "<p>Thanks for your order.</p>",
    "text_body": "Thanks for your order.",
    "tags": ["order-confirmation"],
    "tracking_settings": {"open_tracking": true, "click_tracking": true}
  }' \
  "https://api.telnyx.com/v2/email_messages"

Primary response fields:

• .data.id, .data.status, .data.from, .data.to, .data.cc, .data.bcc
• .data.subject, .data.template_id, .data.attachments, .data.events
• .data.created_at, optional .data.scheduled_at, .data.sandbox, and .data.recipient_statuses
• optional top-level .suppressed[] when some recipients were removed but at least one remains

Send a batch

Send 1–50 independent messages. Always parse both success and error arrays from the 207 response.

POST /v2/email_messages/batch

Parameter	Type	Required	Description
messages	array[message]	Yes	1–50 items; each has the single-send shape except the three threading fields.
sandbox_mode	boolean	No	Applies to every item and overrides item-level sandbox_mode.
Idempotency-Key	header string	No	Idempotency for the whole batch request.

curl --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: d6aa99f9-df20-4caf-99aa-e4c8b67e80ef" \
  -d '{
    "messages": [
      {
        "from": "alerts@example.com",
        "to": ["one@example.net"],
        "subject": "Alert one",
        "text_body": "First alert"
      },
      {
        "from": "alerts@example.com",
        "to": ["two@example.net"],
        "subject": "Alert two",
        "text_body": "Second alert"
      }
    ]
  }' \
  "https://api.telnyx.com/v2/email_messages/batch"

Primary response fields:

• .data[] — successful EmailMessage objects
• .errors[] — failed items with zero-based index, code, and message
• .meta.total, .meta.succeeded, .meta.failed

Schedule and cancel an email

Scheduling uses the normal create endpoint. Confirm .data.status == "scheduled"; an invalid or past timestamp is silently treated as an immediate send.

# Schedule for a future time (compute dynamically so the value is always in the future)
SCHEDULED_AT=$(date -u -v+1H '+%Y-%m-%dT%H:%M:%SZ' 2>/dev/null || date -u -d '+1 hour' '+%Y-%m-%dT%H:%M:%SZ')

# Capture the scheduled message ID for cancellation below
EMAIL_ID=$(curl -s --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "reminders@example.com",
    "to": ["customer@example.net"],
    "subject": "Appointment reminder",
    "text_body": "Your appointment is tomorrow.",
    "scheduled_at": "'$SCHEDULED_AT'"
  }' \
  "https://api.telnyx.com/v2/email_messages" | jq -r '.data.id')

Cancel only while the message is still scheduled:

DELETE /v2/email_messages/{email_id}/schedule

curl --fail-with-body \
  -X DELETE \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  "https://api.telnyx.com/v2/email_messages/$EMAIL_ID/schedule"

The cancel response is an EmailMessageResponse whose .data.status is cancelled.

List and retrieve messages

GET /v2/email_messages uses newest-first cursor pagination and has no filters. GET /v2/email_messages/{id} returns the detail shape, including bodies.

Parameter	Type	Required	Description
page_size	integer 1–100	No	Defaults to 25; invalid values are clamped.
page_cursor	string	No	Opaque URL-safe Base64 cursor from the preceding response.
id	UUID path	For get	Email message ID.

curl --get --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  --data-urlencode "page_size=25" \
  --data-urlencode "page_cursor=$PAGE_CURSOR" \
  "https://api.telnyx.com/v2/email_messages"

curl --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  "https://api.telnyx.com/v2/email_messages/$EMAIL_ID"

The detail response adds .data.text_body and .data.html_body. Continue pagination only when .meta.page_cursor is present.

---

Webhook Verification

Telnyx signs webhook requests with Ed25519 using the telnyx-signature-ed25519 and telnyx-timestamp headers.

# Verify the signature against: telnyx-timestamp + "|" + the exact raw body.
# Do not parse/re-serialize JSON before verification.
# Reject timestamps more than 5 minutes outside your server clock.
# Deduplicate by event ID, then enqueue work and return 2xx quickly.
# Ed25519 is asymmetric signature verification; it is not HMAC.

Webhooks

Outbound lifecycle normally progresses:

email.queued → email.sending → email.sent → email.delivered

Terminal alternatives include email.bounced and email.failed; deferred, complaint, engagement, unsubscribe, sandbox, and scheduled events may also occur.

Email webhooks are configured per sender domain—not per message—using POST /v2/email_domains/{domain_id}/webhooks. A message-send request has no webhook_url parameter.

Telnyx retries webhook deliveries on timeout or non-2xx responses. Keep your endpoint idempotent — the same event may be delivered multiple times. Return 2xx within 10 seconds to acknowledge receipt.

curl --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://example.net/webhooks/email",
    "events": ["email.sent", "email.delivered", "email.bounced", "email.failed"]
  }' \
  "https://api.telnyx.com/v2/email_domains/$DOMAIN_ID/webhooks"

The webhook subscription enum is not the pollable event enum. In particular, cancelled, daily_limit_exceeded, and system/gateway rejection events can be pollable without being subscribable webhooks. Conversely, subscriptions use email.* names while polling uses unprefixed values such as delivered. Read the complete enum and payload reference before writing event dispatch code.

---

Important Supporting Operations

Use these when the core send flow needs a follow-up, reusable content, reporting, or pre-send address checks.

Inspect message events and recipient states

Operation	Endpoint	Optional query parameters
List one message's events	GET /v2/email_messages/{email_id}/events	page_size, page_cursor
List one message's recipients	GET /v2/email_messages/{email_id}/recipients	page_size, page_cursor, status, kind
Get one recipient	GET /v2/email_messages/{email_id}/recipients/{recipient_id}	None

curl --get --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  --data-urlencode "page_size=25" \
  --data-urlencode "page_cursor=$PAGE_CURSOR" \
  "https://api.telnyx.com/v2/email_messages/$EMAIL_ID/events"

curl --get --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  --data-urlencode "status=bounced" \
  --data-urlencode "kind=to" \
  "https://api.telnyx.com/v2/email_messages/$EMAIL_ID/recipients"

curl --get --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  "https://api.telnyx.com/v2/email_messages/$EMAIL_ID/recipients/$RECIPIENT_ID"

Recipient status values are queued, sending, sent, deferred, delivered, bounced, failed, gw_reject, and cancelled. Each recipient has its own billable flag and SMTP outcome. BCC addresses are returned as null.

Create, manage, and render templates

Templates use Liquid. Create requires only name; subject and bodies may be null, and variables are auto-extracted when omitted.

Operation	Endpoint	Body or query
Create	POST /v2/email_templates	name; optional subject, html_body, text_body, variables
List	GET /v2/email_templates	optional page_size, page_cursor
Get	GET /v2/email_templates/{id}	None
Replace	PUT /v2/email_templates/{id}	Any template fields; despite the name, behaves identically to PATCH
Update	PATCH /v2/email_templates/{id}	One or more template fields
Delete	DELETE /v2/email_templates/{id}	None; success is 204 with no body
Render	POST /v2/email_templates/{id}/render	optional template_variables; defaults to {}

curl --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 91f8e70a-9ca0-43c7-b77c-594935493637" \
  -d '{
    "name": "order-confirmation",
    "subject": "Order {{ order_id }} received",
    "html_body": "<p>Hello {{ customer_name }}</p>"
  }' \
  "https://api.telnyx.com/v2/email_templates"

curl --get --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  --data-urlencode "page_size=25" \
  --data-urlencode "page_cursor=$PAGE_CURSOR" \
  "https://api.telnyx.com/v2/email_templates"

curl --get --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  "https://api.telnyx.com/v2/email_templates/$TEMPLATE_ID"

curl --fail-with-body \
  -X PUT \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "order-confirmation-v2",
    "subject": "Order {{ order_id }} confirmed"
  }' \
  "https://api.telnyx.com/v2/email_templates/$TEMPLATE_ID"

curl --fail-with-body \
  -X PATCH \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"subject":"Order {{ order_id }} is confirmed"}' \
  "https://api.telnyx.com/v2/email_templates/$TEMPLATE_ID"

curl --fail-with-body \
  -X DELETE \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  "https://api.telnyx.com/v2/email_templates/$TEMPLATE_ID"

curl --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"template_variables":{"order_id":"A-100","customer_name":"Ada"}}' \
  "https://api.telnyx.com/v2/email_templates/$TEMPLATE_ID/render"

List account events and statistics

GET /v2/email_events lists account events oldest first. It accepts event_type as comma-separated or repeated parameters, plus email_id, from, and to. GET /v2/email_events/stats accepts from and to and returns recipient-level counts and rates.

curl --get --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  --data-urlencode "event_type=delivered,bounced" \
  --data-urlencode "from=2026-07-01T00:00:00Z" \
  --data-urlencode "to=2026-07-31T23:59:59Z" \
  "https://api.telnyx.com/v2/email_events"

curl --get --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  --data-urlencode "from=2026-07-01T00:00:00Z" \
  --data-urlencode "to=2026-07-31T23:59:59Z" \
  "https://api.telnyx.com/v2/email_events/stats"

When from is omitted it defaults to 30 days ago. If from is present without to, the end defaults to from + 30 days.

Validate email addresses

Single validation is synchronous. Batch validation accepts 1–1,000 addresses, deduplicates them, and returns an asynchronous job to poll.

curl --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"email":"customer@example.net"}' \
  "https://api.telnyx.com/v2/email_validations"

curl --fail-with-body \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "emails":["one@example.net","two@example.net"],
    "webhook_url":"https://example.net/webhooks/validation-complete"
  }' \
  "https://api.telnyx.com/v2/email_validations/batch"

curl --fail-with-body \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  "https://api.telnyx.com/v2/email_validations/batch/$BATCH_ID"

Poll until .data.status is completed or failed; completed results are in .data.results, keyed by the original address.

---

Additional Operations

The 20 operations below are reachable. Use the core tasks above first, then consult references/api-details.md for every optional parameter and full response shape. There are no curl SDK methods: use the raw HTTP method and path shown here.

Operation	HTTP method	Endpoint	Use when	Required params
Send, schedule, or sandbox an email	POST	/v2/email_messages	Create one outbound message.	from, to; subject unless template_id
Send a batch	POST	/v2/email_messages/batch	Create up to 50 messages and parse per-item outcomes.	messages
List messages	GET	/v2/email_messages	Page through account messages.	None
Get a message	GET	/v2/email_messages/{id}	Retrieve bodies and current state.	id
Cancel a scheduled message	DELETE	/v2/email_messages/{email_id}/schedule	Stop a message that is still scheduled.	email_id
List message events	GET	/v2/email_messages/{email_id}/events	Poll one message's lifecycle.	email_id
List message recipients	GET	/v2/email_messages/{email_id}/recipients	Inspect per-recipient outcomes.	email_id
Get one message recipient	GET	/v2/email_messages/{email_id}/recipients/{recipient_id}	Inspect one recipient's SMTP state.	email_id, recipient_id
Create a template	POST	/v2/email_templates	Store reusable Liquid content.	name
List templates	GET	/v2/email_templates	Select or audit templates.	None
Get a template	GET	/v2/email_templates/{id}	Retrieve one template.	id
Replace a template	PUT	/v2/email_templates/{id}	Compatibility update; behaves like PATCH.	id
Update a template	PATCH	/v2/email_templates/{id}	Modify selected template fields.	id
Delete a template	DELETE	/v2/email_templates/{id}	Remove reusable content.	id
Render a template	POST	/v2/email_templates/{id}/render	Preview Liquid output.	id
List account events	GET	/v2/email_events	Query pollable lifecycle/engagement events.	None
Get event statistics	GET	/v2/email_events/stats	Compute recipient-level counts and rates.	None
Validate one address	POST	/v2/email_validations	Synchronously assess deliverability.	email
Create a validation batch	POST	/v2/email_validations/batch	Validate up to 1,000 addresses asynchronously.	emails
Get a validation batch	GET	/v2/email_validations/batch/{id}	Poll batch status and retrieve results.	id

Not yet available

These OpenAPI operations are not routed in the deployed API. Do not call them or count them among the 20 reachable operations:

Operation	Endpoint	Status
Delete all account email data matching an address	DELETE /v2/email_messages?address=...	Not yet available
Delete one email message and retained child data	DELETE /v2/email_messages/{id}	Not yet available

---

For exhaustive operation parameters, complete response schemas, webhook fields, and error codes, see references/api-details.md.