Cloud Object Storage

Secure, stable, massive, convenient, low-delay, low-cost cloud storage services


Tencent Cloud Object Storage (COS) is a distributed storage service offered by Tencent Cloud for unstructured data and accessible via HTTP/HTTPS protocols. It can store massive amounts of data and features imperceptible bandwidth and capacity expansion, making it a perfect data pool for big data computation and analytics. COS provides a web-based management interface, multilingual SDK as well as command-line and graphical tools and is fully compatible with S3's API, allowing direct access to community tools and plugins with ease. It can also be used alongside other cloud products such as global CDN nodes for acceleration services and Cloud Image for one-stop image solutions.


Stable and Durable

COS enables redundant storage of data across multiple architectures and devices and supports remote disaster recovery and resource isolation to provide up to 99.999999999% data persistence for each object, providing better data persistence than other storage architectures.

Secure and Reliable

Hotlink protection is supported to block malicious access. Data transmission can be encrypted with SSL technology to control the read/write permission of each file. Defense systems can effectively defend against DDoS and CC attacks to ensure your business operates normally.

Low Costs

There is no need for the traditional purchase, deployment and OPS, or to pay to reserve storage space in advance. The service is used as needed, and billed based on use. Lifecycle management can be used to identify cold data to further reduce costs.

Ease of Use

COS supports a variety of methods for conducting batch operations on storage objects such as graphical programs, command-line tools and protocol tools, further enhancing its ease of use. It also offers tools capable of mounting buckets to your local storage, enabling you to use COS just like a local file storage system.

Convenient Access

COS has a detailed RESTful API manual and a wide variety of SDK connection tools. There is also a seamless migration tool to quickly migrate your business into the cloud, helping you avoid high migration and connection costs.

Service Integration

COS can be integrated with other Tencent Cloud products, including CDN acceleration, Cloud Image processing, audio/video transcoding, file preview and other components, to provide an integrated solution for storage and processing. In addition, COS can be used as a data pool for big data computing and provide the data source for big data analysis and computing.


Object Management

Resume uploads from the breakpoint

If an upload is unexpectedly terminated, you can resume the upload from the breakpoint to reduce the time spent on repeated uploads.

Customize object headers

The object header is a string sent by a server before it sends HTML data to a browser via the HTTP protocol. You can change the response mode of a page or send configuration information by modifying the header. For example, the cache expiration time can be changed, but the file itself will not be changed.

Static websites

Static websites only contain static content (such as HTML) or client-side scripts. Users who don't need to display dynamic webpages can use COS to complete the whole process from storage to display. Users can host a static website by configuring a bucket (linked with a custom domain name) for the website on COS.

Storage Classes

Tencent Cloud Object Storage (COS) provides a variety of storage classes suitable for different scenarios, including COS standard for frequently accessed data, COS infrequent access for business scenarios with low access frequency, and archive storage for archived data that needs to be stored for a long time.

COS Standard

COS Standard is an object storage service with high reliability, availability, and performance.Its low latency and high throughput make it well suitable for the use cases involving lots of hotspot files or frequent data access.
  • Features: High reliability, availability, and performance
  • Use Cases: Trending videos, social networking photos, mobile apps, games, and dynamic websites.
  • Data persistence: 99.999999999%
  • Service availability: 99.95%
  • Response: Within milliseconds
  • Supported regions: All
  • Storage cost: Standard

COS Standard_IA

COS Infrequent Access (COS Standard_IA) provides object storage services featuring high reliability and low storage cost and access latency. It offers lowered pricing for storage and keeps the first-byte access time within milliseconds, ensuring that data can be fast retrieved with no wait required. However, data retrieval incurs fees. It is suitable for business scenarios where the access frequency is low (e.g., once or twice per month).
  • Features: Low-frequency access, real-time response
  • Use Cases: Online file storage, big data analytics, governmental/organizational business data, low-frequency archives, and monitoring data.
  • Data persistence: 99.999999999%
  • Service availability: 99.9%
  • Minimum billing duration: 30 days
  • Minimum object size: 64 KB
  • First-byte delay: Within milliseconds
  • Supported regions: All
  • Storage cost: Low

Archive Storage

Archive Storage is a highly reliable object storage service that has ultra-low storage cost and long-term data retention. Featuring the lowest storage price, Archive Storage needs a longer time to read data and is suitable for archived data that needs to be stored for a long time.
  • Features: High data persistence and service availability, low cost
  • Use Cases: Archive of compliance documents (e.g., archival data, medical images, and scientific materials), lifecycle files, operational logs, and remote disaster recovery.
  • Data persistence: 99.999999999%
  • Service availability: 99.9%
  • Minimum billing duration: 90 days
  • Minimum object size: 64 KB
  • Response: Prior application for data restoration required
  • Supported regions: Public cloud regions only
  • Storage cost: Very low


Application Data Storage

Whether it's a mobile app, a website or an HTML5 page, COS provides SDKs written in various languages based on application types for seamless access. In case of business or user-generated content (UGC) peaks, COS scales automatically in accordance with the amounts of requests and traffic to cope with massive business access. As UGC typically has time-dimensional access characteristics, COS can stratify cold and hot data to use standard storage for hot data and low-frequency storage for cold data. Together with the lifecycle rule configuration and storage type conversion, COS reduces storage costs.

Content Distribution

Web services generally separate frequently-changed resources from infrequently-changed resources in dynamic webpages according to a particular rule. Static resources refer to unstructured data resources that remain unchanged for a long time.

COS Standard allows static resources to be stored and distributed so as to relieve the pressure on resource servers. With infinite capacity and highly frequent read/write capabilities, the scalability and reliability of static resources are assured. Users can host the static content (including audio/video files and images) of a website in COS Standard and distribute content using Tencent Cloud CDN. Using the capacity of Tencent Cloud CDN global acceleration nodes, users can distribute hot files to edge nodes ahead of time to minimize access latency.

Big Data Analysis

COS can be used as a data source for big data analysis regardless of the type of data (medical or financial data, or multimedia files such as images, audio and video).

COS supports the storage of exabytes of unconstructed data, providing high availability, high reliability, high security and high scalability. Analysis apps can be rapidly built and deployed using the Tencent Cloud Big Data Suite. After your high performance computing need is met, you can archive the data to reduce service costs and store the data long term.

Disaster Recovery and Backup

Data uploaded to COS can be stored in multiple designated regions simultaneously by utilizing cross-regional duplication, ensuring that redundant data can be used to find and recover complete sets of data in a situation of accidental loss of partial data. In addition, by virtue of storing data across different regions, data loss caused by unavoidable disasters in one region can be circumvented, making multi-redundancy backup and cross-regional disaster recovery possible and ensuring data persistence and stability with yet another layer of security.


COS fees are broken down into five categories: storage capacity, requests, data retrievals, traffic and management feature fees. Traffic fees and management feature fees are billed daily, where the fees for the day are calculated and billed the following day. The remaining billable items are on a monthly billing cycle, where the fees for the month are calculated and billed on the 3rd to 5th day of the following month. Your bills can be viewed in the Tencent Cloud Console.

For directions, see Viewing Billing Details.