Telegram Gateway API

The Gateway API is an HTTP-based interface created for developers looking to deliver automated messages, such as verification codes, to users who registered their phone number on Telegram.

This page outlines the full API documentation for developers. For more information on the API and the features it offers, see our Verification Platform Overview and Gateway API Tutorial.

Making requests

All queries to the Telegram Gateway API must be served over HTTPS and need to be presented in this form: https://gatewayapi.telegram.org/METHOD_NAME. Like this for example:

https://gatewayapi.telegram.org/sendVerificationMessage

We support GET and POST HTTP methods. We support three ways of passing parameters in Gateway API requests:

The response contains a JSON object, which always has a Boolean field ok. If ok equals true, the request was successful, and the result of the query can be found in the result field. In case of an unsuccessful request, ok equals false, and the error is explained in the error field (e.g. ACCESS_TOKEN_INVALID).

  • All methods in the Gateway API are case-insensitive.
  • All queries must be made using UTF-8.

Authorization

Before invoking API methods, you must obtain an access token in the Telegram Gateway account settings.

The token must be passed in every request in one of two ways:

  • in the HTTP header: Authorization: Bearer <token>
  • as the access_token parameter.

Available methods

We support GET and POST HTTP methods. Use either URL query string or application/json or application/x-www-form-urlencoded for passing parameters in Telegram Gateway API requests.
On successful call, a JSON object containing the result will be returned.

sendVerificationMessage

Use this method to send a verification message. Charges will apply according to the pricing plan for each successful message delivery. Note that this method is always free of charge when used to send codes to your own phone number. On success, returns a RequestStatus object.

Parameter Type Required Description
phone_number String Yes The phone number to which you want to send a verification message, in the E.164 format.
request_id String Optional The unique identifier of a previous request from checkSendAbility. If provided, this request will be free of charge.
sender_username String Optional Username of the Telegram channel from which the code will be sent. The specified channel, if any, must be verified and owned by the same account who owns the Gateway API token.
code String Optional The verification code. Use this parameter if you want to set the verification code yourself. Only fully numeric strings between 4 and 8 characters in length are supported. If this parameter is set, code_length is ignored.
code_length Integer Optional The length of the verification code if Telegram needs to generate it for you. Supported values are from 4 to 8. This is only relevant if you are not using the code parameter to set your own code. Use the checkVerificationStatus method with the code parameter to verify the code entered by the user.
callback_url String Optional An HTTPS URL where you want to receive delivery reports related to the sent message, 0-256 bytes.
payload String Optional Custom payload, 0-128 bytes. This will not be displayed to the user, use it for your internal processes.
ttl Integer Optional Time-to-live (in seconds) before the message expires and is deleted. The message will not be deleted if it has already been read. If not specified, the message will not be deleted. Supported values are from 60 to 86400.

checkSendAbility

Use this method to check the ability to send a verification message to the specified phone number. If the ability to send is confirmed, a fee will apply according to the pricing plan. After checking, you can send a verification message using the sendVerificationMessage method, providing the request_id from this response.

Within the scope of a request_id, only one fee can be charged. Calling sendVerificationMessage once with the returned request_id will be free of charge, while repeated calls will result in an error. Conversely, calls that don't include a request_id will spawn new requests and incur the respective fees accordingly. Note that this method is always free of charge when used to send codes to your own phone number.

In case the message can be sent, returns a RequestStatus object. Otherwise, an appropriate error will be returned.

Parameter Type Required Description
phone_number String Yes The phone number for which you want to check our ability to send a verification message, in the E.164 format.

checkVerificationStatus

Use this method to check the status of a verification message that was sent previously. If the code was generated by Telegram for you, you can also verify the correctness of the code entered by the user using this method. Even if you set the code yourself, it is recommended to call this method after the user has successfully entered the code, passing the correct code in the code parameter, so that we can track the conversion rate of your verifications. On success, returns a RequestStatus object.

Parameter Type Required Description
request_id String Yes The unique identifier of the verification request whose status you want to check.
code String Optional The code entered by the user. If provided, the method checks if the code is valid for the relevant request.

revokeVerificationMessage

Use this method to revoke a verification message that was sent previously. Returns True if the revocation request was received. However, this does not guarantee that the message will be deleted. For example, it will not be removed if the recipient has already read it.

Parameter Type Required Description
request_id String Yes The unique identifier of the request whose verification message you want to revoke.

Available types

All types used in Telegram Gateway API responses are represented as JSON objects.

It is safe to use 32-bit signed integers for storing all Integer fields unless otherwise noted.

Optional fields may be not returned when irrelevant.

RequestStatus

This object represents the status of a verification message request.

Field Type Description
request_id String Unique identifier of the verification request.
phone_number String The phone number to which the verification code was sent, in the E.164 format.
request_cost Float Total request cost incurred by either checkSendAbility or sendVerificationMessage.
remaining_balance Float Optional. Remaining balance in credits. Returned only in response to a request that incurs a charge.
delivery_status DeliveryStatus Optional. The current message delivery status. Returned only if a verification message was sent to the user.
verification_status VerificationStatus Optional. The current status of the verification process.
payload String Optional. Custom payload if it was provided in the request, 0-256 bytes.

DeliveryStatus

This object represents the delivery status of a message.

Field Type Description
status String The current status of the message. One of the following:
- sent – the message has been sent to the recipient's device(s),
- read – the message has been read by the recipient,
- revoked – the message has been revoked.
updated_at Integer The timestamp when the status was last updated.

VerificationStatus

This object represents the verification status of a code.

Field Type Description
status String The current status of the verification process. One of the following:
- code_valid – the code entered by the user is correct,
- code_invalid – the code entered by the user is incorrect,
- code_max_attempts_exceeded – the maximum number of attempts to enter the code has been exceeded,
- expired – the code has expired and can no longer be used for verification.
updated_at Integer The timestamp for this particular status. Represents the time when the status was last updated.
code_entered String Optional. The code entered by the user.

Report delivery

The Telegram Gateway API can send delivery reports to a user-specified callback URL. When you include a callback_url parameter in your request, the API will send an HTTP POST request to that URL containing the delivery report for the message. The payload of the POST request will be a JSON object representing the RequestStatus object.

Your URL must respond with HTTP status code 200 to acknowledge receipt of the report. Any other status code will be considered a failure, and the service will retry sending the same report up to 10 times with increasing delays between attempts. If all retries fail, the report will be considered lost.

Checking report integrity

All reports submitted to your callback_url, if you provided one, will also contain the following headers:

  • X-Request-Timestamp – A Unix timestamp indicating when the server submitted the report.
  • X-Request-Signature – A server-generated signature needed to authenticate the report on your end.

You can confirm the origin and verify the integrity of the reports you receive by comparing the signature contained in the X-Request-Signature header with the hexadecimal representation of the HMAC-SHA-256 signature of the data-check-string with the SHA256 hash of the API token shown in your Gateway account settings.

The data-check-string is a concatenation of the report timestamp as provided by the X-Request-Timestamp header, a line feed character ('\n', 0x0A) used as separator and the raw post body of the HTTP request.

Example:

data_check_string = X-Request-Timestamp + '\n' + post_body
secret_key = SHA256(api_token)
if (hex(HMAC_SHA256(data_check_string, secret_key)) == X-Request-Signature) {
  // data is from Telegram
}

To prevent the use of outdated data, you should additionally check the X-Request-Timestamp header, which contains a Unix timestamp of when the relevant report was submitted by the server.