This topic describes the characteristics, use cases, application process, and lifecycle management of different number types in Voice Messaging Service. Select, apply for, and manage voice numbers based on your business requirements.
Number types and selection
Voice Messaging Service provides multiple number types to meet different business needs. Before choosing a number, understand the characteristics and differences of each type to select the best option for your business.
Number type | Supported direction | Application method | Billing model | Use cases |
400 number | Inbound only | Apply for a number in the console.
| Package fee + usage fee No fixed monthly fee, but a minimum monthly charge applies. | Enterprise service hotlines: Serves as a unified, nationwide brand number for receiving customer calls. |
Regular number (landline & mobile number) | Supports inbound and outbound | Apply for a number in the console.
| The monthly fee is 35 CNY/month. | Two-way calling and outbound notifications: Ideal for scenarios requiring two-way voice communication or outbound calls. |
Public mode | Outbound only | No number application required Ready to use immediately after service activation. | Pay-as-you-go, with no monthly fee for numbers. | Voice notifications and verification codes: A cost-effective option for sending one-way voice content. |
Decision recommendations:
To establish an enterprise service hotline for inbound calls only, apply for a 400 number.
If you only need to send voice notifications or verification codes, use the public mode. It is the most convenient option, as you do not need to purchase or manage numbers.
If you already have a regular number, see "Manage purchased numbers" for maintenance instructions.
Prerequisites
You have completed enterprise qualification management and passed the review.
You have added a script and it has been approved.
You have applied for a real number.
Inbound audio playback compliance
When you open the real number management page, a compliance notice for inbound audio playback appears at the top. This notice reminds you to configure the inbound audio playback feature. It covers the carrier compliance requirements, such as ensuring smooth inbound call routing and configuring inbound audio playback. It also describes two configuration methods: using the IVR tool in the console or contacting customer support. Finally, it warns that without configuration, your number may be restricted by the carrier, and default rules will be enforced starting June 1, 2026.
The first time you visit the real number management page, a "Configure IVR Audio Playback" dialog box appears. You must select the I acknowledge and agree checkbox to close it. The system records your confirmation, and the dialog box does not appear on subsequent visits.
For more information about the configuration, see Configure inbound audio playback.
Apply for a 400 number (inbound only)
400 numbers are available in different package tiers, ranging from 120 to 5,000 CNY, with a usage rate of 0.11 CNY/minute. There is no monthly fee, but a minimum monthly charge of 120 CNY applies. Numbers activated during a month are billed for the entire month's fee, so we recommend applying for new numbers at the beginning of the month.
Log on to the Voice Messaging Service console. In the left-side navigation pane, choose .
Click Purchase Number and fill out the application as prompted:
Enterprise Name: Select your enterprise name from the list of approved 400 qualifications.
Provider: Select a number provider from the list.
Number: Select a 400 number from the list of available numbers. You can click Change to refresh the list.
After selecting a number, an inbound audio playback compliance confirmation panel appears. Please read the following information carefully:
Carrier requirements: To prevent telecommunication fraud and regulate number usage, carriers require that the number you apply for has a smooth inbound call path. After activation, you must configure inbound audio playback. Failure to do so may result in your number being restricted by the carrier and becoming unusable.
Default rules: To ensure your service operates correctly, the platform will, with your authorization, apply default inbound call answering and audio playback rules. This may incur fees (see China Mainland Voice Messaging Service Pricing or contact your account manager). Proceeding with number activation constitutes agreement to these default rules.
Self-service configuration: If you want to customize the playback content, the platform provides a self-service IVR audio playback feature. You can configure it in the "real number management" section after the number is activated. For details, see Configure inbound audio playback.
Important: After applying, you must submit the required documents for review. If the documents are not submitted within 15 days, the number will be released.
After reading, select the I acknowledge and agree checkbox.
After you agree, click Apply Now.
After you apply, you must submit specific documents for review. The number will be released if the documents are not submitted within 15 days.
Hover over Reason in the Running Status column to view the reason for the timeout release.
Click Deregister in the Actions column to deregister the number.
Manage purchased numbers
This section describes how to manage numbers you already own, including regular numbers and 400 numbers. On the real number management page, on the Landline & mobile number or 400 numbers tab, find the number you want to manage and perform actions in the Actions column.
In the number list on the real number management page, the Call Type column displays call type information based on the value of the ResCallTypeDesc field in the returned data.
Bind an instance
Service instances can only be bound to real numbers in the landline & mobile number category.
Binding a number to a service instance associates it with a specific set of configurations—such as IVR flows, recording settings, and agent assignments—to handle voice calls. A service instance is a set of functional configurations in Voice Messaging Service.
In the Actions column for the target number, click Bind Instance.
In the dialog box that appears, select the service instance to bind from the drop-down list.
Click OK to complete the binding.
Deregister a number
This action permanently deregisters the number and is irreversible. After you deregister the number, it cannot be recovered, and all related services will be terminated.
Before proceeding, ensure the number is not associated with any business services to avoid disruptions.
In the Actions column for the target number, click Deregister.
In the confirmation dialog box, carefully read the risk warnings.
A regular number can only be deregistered after it has been active for at least three months.
The fixed fee (such as the monthly fee) for the month in which you deregister the number will still be charged and is non-refundable. Ensure that your account has a sufficient balance and no outstanding payments.
After you confirm, click OK. The number will enter the deregistration process.
Take note of the following:
Deregistration billing — Numbers are scarce resources. Charges begin in the month of activation, and a full monthly fee applies even if the number is active for less than a full month.
Batch deregistration — To keep specific numbers and deregister the rest, perform the operation on the Real number management page.
Number change restriction — Numbers that have been successfully applied for do not support region changes or number replacements. If your concurrency capacity is insufficient, expand it by applying for additional numbers.
Number attributes and features
This section summarizes methods for querying key number attributes and common feature restrictions to help you better understand and use purchased numbers.
Inbound permission verification — On the Real number management page, view the number details. If the Call Type column contains "Inbound," the number has inbound calling enabled.
Special number identification — Numbers with the prefix 95, 96, or 400 are special service numbers and are managed differently from regular numbers.
Outbound blind zone query — On the Real number management page, you can view the list of unsupported regions (blind zones) for the calling number. Blind zones refer to regions where calls cannot be placed due to carrier restrictions.
Concurrency — The actual concurrency of a number is subject to what is displayed in the console after the number is activated. The default concurrency values noted in documentation are for general reference only.
Cross-account restriction — Voice numbers cannot be used or transferred across accounts. Each account must apply for numbers independently and complete the qualification review.
Difference between business modes:
Dedicated mode — Customers can apply for a number to initiate outbound calls.
Public mode — Outbound calls are made using numbers from a shared number pool, with numbers displayed randomly.
Service stop — Voice Messaging Service does not have a Stop/Restart operation. Even if you do not make outbound calls, monthly fees will still be charged as long as there are underegistered numbers in your account. To stop billing, Deregister the number in the console.
FAQ
Why can't I deregister a number immediately after applying for it?
What types of numbers are available for Voice Messaging Service?
How do users obtain a voice number when using voice products?
Can I disable inbound calling or change the call type for a voice number?
For an applied real voice number, the call type (inbound/outbound) is determined at the time of application and cannot be modified afterward. You cannot disable inbound calling separately.
If your business only requires outbound calls (such as voice verification codes), select the outbound-only option when applying for a new number. Numbers that are already activated cannot have their purpose changed.
Even if a number displays "Inbound + Outbound" in the console, if the actual line only supports outbound, this is a display anomaly and does not affect your actual service. No additional action is required.
What should I do if a voice number is marked as spam, causing calls to fail?
Symptom: The API call succeeds, but the called party does not receive the call.
Cause: Due to high call frequency or prolonged use, the number is flagged as spam by third-party security software or carriers. Even if the calling number has been added to an allowlist, calls may still be intercepted by the called party's carrier.
Solution:
Apply for a new dedicated number for outbound calls. New numbers have no initial flag and can improve call connection rates.
Try switching to a different calling number for testing.
Deactivating a flagged number does not automatically remove the flag. The time required to clear the flag depends on mobile device manufacturers or security software policies, and Alibaba Cloud cannot intervene.