Bulk Voice Call &
Cloud Telephony in India

A bulk Voice call, also called an outbound dialer or OBD, plays a pre-recorded Voice message to a list of phone numbers automatically. You upload the audio and the numbers; the platform dials each number, plays the message when the call is answered, and reports which calls were answered, missed, busy or blocked. Businesses use it for reminders, alerts, announcements and promotional offers because a call is heard even by customers who never read SMS.

Voice calls are billed at ₹0.25 per 15-second pulse, and only for calls that were answered. A 12-second message that is picked up costs one pulse (₹0.25); a 30-second message costs two pulses (₹0.50); a 45-second message costs three pulses (₹0.75). Calls that were missed, busy, switched off or blocked by DND are not charged at all. There is no setup fee and no monthly platform fee; you recharge from ₹100 and pay as you go.

No. You pay only for answered calls. Missed calls, busy numbers, switched-off handsets, invalid numbers and DND-blocked numbers cost nothing. If a charge is ever applied to such a call, the amount is credited back to your wallet automatically within 48 hours and shows in your transaction history with the campaign name.

A call is answered when the customer picks up and the audio starts playing. The duration counted for billing is the time from pick-up to hang-up, rounded up to the next 15-second pulse. If the customer hangs up after six seconds, that is still one pulse. The per-number report shows the exact duration, the pulses and the charge for every answered call.

Operators sometimes confirm a call's final status a few hours after the campaign, for example a call that first appeared connected but was actually not answered. Our system reconciles every campaign against the operator's final records and credits back any amount debited for a call that was not answered. This happens automatically within 48 hours, and each refund is listed in the transaction history.

Transactional calls, such as payment reminders, appointment confirmations, delivery updates and OTPs, are delivered to all numbers including DND. Promotional calls, such as offers and sales announcements, are delivered only to Non-DND numbers as required by TRAI. When you mark a campaign as promotional, DND numbers are removed before dialling and are never charged.

Promotional Voice calls are placed between 9 am and 9 pm. If you schedule a promotional campaign outside that window, it is held and dialled from the next permitted time. Transactional calls such as OTPs and reminders can be placed at any time.

MP3 and WAV files are accepted, and you can also record the message directly in the panel. Keep promotional messages short, ideally within 15 to 30 seconds, because customers decide in the first few seconds whether to keep listening and each 15 seconds is one pulse. Transactional reminders are usually 15 to 20 seconds. You can preview the audio before sending.

Voice OTP is a one-time password delivered by an automated call that reads the digits aloud, usually twice. It reaches feature phones, landlines and customers whose SMS inbox is full or filtered by the handset. Most businesses use it as a fallback when an SMS OTP is not delivered within a few seconds, and some use it as the first option for older or voice-first customers.

The call is placed within a few seconds of the API request and the OTP is read out as soon as the customer answers. The OTP is read twice so the customer does not have to ask for a repeat. The API responds immediately with a request ID, and the call status appears in your report.

Use the Smart OTP API: POST https://www.fast2sms.com/dev/otp/send with the mobile number and the OTP ID of a template whose channel is set to Voice call (Smart OTP → Templates in the panel), with your API key in the Authorization header. Fast2SMS generates the code, reads it out on a call and stores it; POST /dev/otp/verify checks what the user typed. The same request sends SMS or WhatsApp OTPs when you pass a template of that channel, and a fallback channel can be set on the template. Code samples for PHP, Node, Python, Java and .NET are in the docs at docs.fast2sms.com.

A cloud number (virtual number) is a business phone number hosted on our platform. Customers call it and the IVR answers, routes them to the right agent or group, and records the call. Your agents can also place outgoing calls that show the cloud number as the caller ID, so customers see one consistent business number. Every call is logged with time, agent, duration and a recording.

A cloud number is billed per number per month as a rental, plus the usual per-pulse charge for incoming and outgoing call minutes. The IVR builder and agents on that number are free. The current monthly rental is shown in the panel when you request a number; for several numbers or higher call volumes, contact sales for a custom rate.

Yes. The IVR flow builder is included at no charge with every cloud number. You can build a welcome message, key-press menus, routing to agents or groups, voicemail and business-hours rules by dragging blocks, and change the flow any time. You pay only the number's monthly rental and the call pulses.

No. Creating agents and call groups is free, however many you add. An agent is a person with a mobile or desk number who receives calls from the IVR; a call group rings several agents in round robin or all at once. Agents can be added, paused or removed from the panel without any change to your bill.

For bulk Voice calls and Voice OTP you need a verified Fast2SMS account with your business details. For a cloud number, operator rules require basic business KYC such as PAN or GST and an address proof before the number is activated; our team collects these during onboarding and activation usually takes one to three working days.

Yes, when it follows TRAI's rules: transactional calls to anyone who has a relationship with your business, promotional calls only to Non-DND numbers and only between 9 am and 9 pm, and a clear identification of who is calling. Fast2SMS applies the DND scrubbing and time window automatically for promotional campaigns.

Yes. Open a campaign and every number is listed with its status (answered, missed, busy, switched off, DND), the call duration, the number of pulses and the charge. Summary counts update in real time while the campaign is running, and the sheet can be exported to Excel.

Any language. You upload or record the audio yourself, so Hindi, English, Marathi, Gujarati, Tamil, Telugu, Kannada, Bengali and every other language work the same way. Many customers record one message per region and run separate campaigns for each list.

Yes. From the campaign report you can select the missed and busy numbers and shoot a retry campaign with one click, or schedule the retry for a later time. Only the calls answered in the retry are charged.

Create a free account with your mobile number and use the ₹50 credit to test a Voice call or a Voice OTP. Then recharge from ₹100, upload your audio and numbers, and shoot your first campaign from the panel. For a cloud number and IVR, request the number in the panel or schedule a meeting and we will set it up with you.