BatChat File Transfer Limits - Size, Speed, and VIP Tiers | BatChatHub

TL;DR

BatChat (蝙蝠聊天) supports file transfer for all common file types including documents, images, videos, and audio. The platform features breakpoint resume (断点续传) for interrupted transfers and supports large file transfers for VIP and SVIP members. Free users can send files in the tens of megabytes range, while higher-tier members can transfer significantly larger files. All file transfers use the same end-to-end encryption as regular messages. BatChat also supports online preview for Office document formats (Word, Excel, PowerPoint, PDF).

What File Types Does BatChat Support?

BatChat supports transmission of a wide range of file types through its chat interface:

• Documents: Word (.doc, .docx), PDF, TXT, and other text-based formats
• Spreadsheets: Excel (.xls, .xlsx), CSV
• Presentations: PowerPoint (.ppt, .pptx)
• Images: JPG, PNG, GIF, BMP, WebP, and other common image formats
• Video: MP4, AVI, MOV, MKV, and other standard video containers
• Audio: MP3, WAV, FLAC, AAC, and common audio formats
• Archives: ZIP, RAR, 7z (compressed file packages)
• Other: Any file type can be sent — BatChat does not restrict based on file extension

The v2.5.0 update enhanced BatChat’s file handling with online preview capabilities for Office documents. Users can now view Word documents, Excel spreadsheets, PowerPoint presentations, and PDF files directly within the chat interface without switching to another application. This is relevant for users who use BatChat for work collaboration.

A “quick annotation” (快速标注) feature was also added in v2.5.0, allowing users to add arrows, text, and mosaics to images before sending them — useful for highlighting specific areas in screenshots during remote work discussions.

File Size Limits: Free vs. VIP vs. SVIP

BatChat’s file transfer capacity scales with membership tier. The platform offers two membership levels: VIP (基础会员) and SVIP (高级会员, with sub-levels SVIP1 through SVIP11).

Free user limits

Free users can transfer files in the range of tens of megabytes per file. The exact ceiling varies based on:

• Network conditions: Available bandwidth affects maximum practical file size
• Device performance: Low-end devices may struggle with large file encryption and transfer
• File type: Compression efficiency varies — a 200MB text file compresses differently than a 200MB video

The practical experience for free users, as reported across multiple review sites, is that files of “几十兆甚至上百兆” (tens to hundreds of megabytes) can be transmitted without issue.

VIP member limits

VIP members (1-month, 3-month, or 6-month subscription) receive expanded transfer capacity compared to free users. The exact file size ceiling is not published in BatChat’s public documentation, but the membership provides additional server resources and priority transfer speeds.

SVIP member limits

SVIP members, particularly at higher levels (SVIP8 through SVIP11), receive the most generous transfer allowances. At the highest tiers, BatChat supports transfers of very large files — with some sources and promotional materials referencing TB-level (terabyte-level) transfer capability for SVIP members.

SVIP tiers are reached through a growth point system:

SVIP Level	Growth Points Required
SVIP1	100
SVIP2	300
SVIP3	650
SVIP4	1,000
SVIP5	1,500
SVIP6	2,100
SVIP7	2,800
SVIP8	3,600
SVIP9	4,500
SVIP10	9,000
SVIP11	14,000

Growth points are obtained by using SVIP membership coupons (1 coupon = 100 points). Reaching higher SVIP levels also increases other limits: SVIP11 users can add up to 9,500 friends, join up to 1,000 groups, and create 7 channels.

Important caveat on published limits

BatChat does not publish a definitive table of exact file size limits per membership tier. The numbers available in public sources are approximate. If you need to transfer a specific file size, testing with a trial VIP/SVIP membership is the most reliable way to confirm the actual limit for your use case.

Breakpoint Resume (断点续传)

One of BatChat’s most practical file transfer features is breakpoint resume (断点续传). This allows file transfers to continue from where they were interrupted rather than starting over from the beginning.

When breakpoint resume activates

• Network interruption: Wi-Fi disconnects, mobile data drops, or network switching mid-transfer
• App backgrounded: The user switches to another app during a large file transfer
• Device sleep: The phone screen turns off during transfer (if background permissions are enabled)
• Sender or receiver crash: Either party’s BatChat app terminates unexpectedly

How it works

1. During a file transfer, BatChat tracks the bytes successfully sent and received
2. If the transfer is interrupted, both sides retain the partial data
3. When the connection is restored, BatChat resumes from the last confirmed byte position
4. The recipient sees the transfer continue rather than restart

This feature is critical for large file transfers. Without breakpoint resume, a 2GB file that is interrupted at 95% completion would require starting over, wasting time and bandwidth. With breakpoint resume, the transfer picks up from the 1.9GB mark.

Enabling background transfer for reliable resume

For breakpoint resume to work reliably when the app is backgrounded:

1. Go to your device’s Settings > Apps > BatChat
2. Enable “Allow background activity” (允许后台活动)
3. On Android: also enable “Auto-start” (自启动) in the device manufacturer’s battery management settings
4. On Xiaomi/Huawei/Oppo: additionally lock BatChat in the recent apps tray to prevent system-level killing

Without these permissions, aggressive battery management on some Android devices may terminate the transfer process entirely, forcing a restart rather than a resume.

File Transfer Speed

File transfer speed in BatChat depends on several factors:

Network bandwidth

The primary bottleneck is the network connection of both the sender and receiver. The effective transfer speed is limited by the slower of the two connections:

• Wi-Fi: Typically 10-100 Mbps depending on router and device — sufficient for most file transfers
• 4G/LTE: 5-50 Mbps — adequate for small to medium files but slow for large transfers
• 5G: Potentially 100+ Mbps — suitable for large file transfers on supported networks

Encryption overhead

All BatChat file transfers are end-to-end encrypted. The encryption process (asymmetric encryption + Double Ratchet) adds computational overhead to each transfer. This overhead is typically minimal (single-digit percentage of total transfer time) but may be noticeable on lower-end devices.

Server relay

BatChat uses a server relay model for file transfers — files are not sent directly between devices but are routed through BatChat’s infrastructure. This means the server bandwidth also affects transfer speed. BatChat has not published specifics about its server infrastructure or relay speeds.

Practical expectations

Based on available reports and the compression optimizations introduced in v2.5.0 (which reduced data transfer volume while maintaining file quality), users on stable Wi-Fi connections can expect:

• Small files (< 10MB): Near-instant, typically under 5 seconds
• Medium files (10-100MB): 10 seconds to a few minutes depending on connection
• Large files (100MB+): Several minutes to potentially hours for multi-GB files, heavily dependent on both parties’ network conditions

How to Send Files in BatChat

Basic file transfer

1. Open the chat conversation (one-on-one or group)
2. Tap the ”+” extension menu next to the input field
3. Select the file type you want to send (photo, video, document, or file)
4. Browse your device storage and select the file
5. Optionally add a caption or message
6. Tap send

The file is encrypted on your device before transmission. The recipient receives an encrypted file that is decrypted on their device.

Sending images with annotations

Available since v2.5.0:

1. Select an image to send
2. Before sending, tap the annotation tool
3. Add arrows, text, or mosaic effects to highlight areas of interest
4. Send the annotated image

This is useful for technical discussions, design feedback, or any scenario where you need to point out specific elements in an image.

File Transfer in Group Chats

File transfer works in BatChat group chats with the same capabilities as one-on-one chats. All file types, sizes (within your tier limits), and features like breakpoint resume are available in groups.

Considerations for group file transfers:

• Download bandwidth: In a 50,000-member group, if the sender shares a large file, only members who choose to download it consume bandwidth. The file is not force-downloaded to all members.
• Storage: Downloaded files in group chats consume the recipient’s device storage. Large files shared in active groups can accumulate.
• Organization: Group admins can pin important shared files using the “精华消息” (pinned/essential messages) feature.

File Transfer Security

All file transfers in BatChat inherit the platform’s security model:

• End-to-end encryption: Files are encrypted on the sender’s device using BatChat’s cryptographic stack (RSA for key exchange, asymmetric encryption for data, Double Ratchet for forward secrecy)
• No server-side storage: BatChat claims zero server data storage (服务器零数据存储), meaning files pass through the server encrypted but are not stored there permanently
• Local encryption: Downloaded files on the recipient’s device benefit from BatChat’s enhanced local data protection introduced in v2.5.0

Security implications

• Even if BatChat’s servers were compromised, intercepted files would be encrypted and unreadable
• Files on the recipient’s device are protected by BatChat’s local encryption, which means a lost or stolen device does not expose file contents without the BatChat app’s authentication
• The application lock feature (应用锁), which requires biometric or PIN authentication to open BatChat, adds another layer of protection for received files

Tips for Efficient File Transfer

For large files

• Use Wi-Fi: Mobile data is slower and may incur data charges for large transfers
• Keep the app foregrounded: Minimize the risk of interruption by keeping BatChat open during the transfer
• Compress first: For documents, ZIP compression can significantly reduce transfer time. For images, consider reducing resolution before sending
• Verify background permissions: Ensure BatChat has permission to run in the background on your device for breakpoint resume to work

For multiple files

• Send individually rather than as an archive if the recipient only needs specific files — this lets them download selectively
• Use a ZIP archive if the recipient needs all files, as a single compressed transfer is often faster than multiple individual transfers
• Batch send during off-peak hours if network speed is a concern in your area

How BatChat File Transfer Compares

Feature	BatChat (Free)	BatChat (SVIP)	WeChat	Telegram	Signal
File size limit	~100MB	Up to TB-level	100MB (free)	2GB (free)	100MB
Breakpoint resume	Yes	Yes	No	Partial	No
End-to-end encryption	Yes	Yes	No	Optional	Yes
Online doc preview	Yes	Yes	Partial	No	No
Image annotation	Yes	Yes	Limited	No	No

BatChat’s advantage is the combination of encryption, breakpoint resume, and document preview in a single platform. Telegram offers larger free file sizes but does not encrypt files by default (only in Secret Chats, which lack many features). WeChat has no end-to-end encryption for file transfers.

Common Problems and Fixes

File transfer fails midway

1. Check your network connection on both sides
2. If using mobile data, switch to Wi-Fi
3. Ensure BatChat has background activity permissions enabled
4. Restart the transfer — breakpoint resume should pick up where it left off
5. If the transfer fails repeatedly at the same point, the file may be corrupted. Try re-exporting or re-saving the file

Transfer speed is very slow

1. Test your internet speed at speedtest.net to rule out connection issues
2. Check if other devices on your network are consuming bandwidth
3. Try transferring at a different time of day
4. Close other apps that may be using network resources
5. On Android, check if battery saver mode is limiting network access for BatChat

File cannot be opened after download

1. Verify the file was fully downloaded — check the file size against the original
2. Ensure you have an app installed that can open the file type
3. Try downloading the file again if it appears corrupted
4. Some file types may not have native support on your device — try a third-party file viewer

Recipient did not receive the file

1. Check that the message shows as delivered (single eye icon for disappearing messages, or sent status for regular messages)
2. The recipient may need to manually download the file if auto-download is disabled in their settings
3. Large files may take time to appear on the recipient’s side, especially on slower connections

FAQ

What is the maximum file size I can send in BatChat as a free user?

Free users can typically send files up to approximately 100MB, depending on network conditions and device performance. The exact limit is influenced by available bandwidth and the file type being transferred.

Does BatChat support breakpoint resume for file transfers?

Yes. BatChat supports breakpoint resume (断点续传) for interrupted file transfers. If a transfer is interrupted by network issues, app backgrounding, or device sleep, it resumes from where it left off when the connection is restored.

What file types can I send through BatChat?

BatChat supports all common file types including documents (Word, PDF, TXT), spreadsheets (Excel, CSV), presentations (PowerPoint), images, video, audio, and archive files (ZIP, RAR). There is no restriction based on file extension.

How do BatChat VIP and SVIP memberships affect file transfer?

VIP members receive expanded transfer capacity compared to free users. SVIP members at higher levels (SVIP8-11) can transfer very large files, with promotional materials referencing TB-level transfer capability for the highest tiers. Higher memberships also provide faster transfer speeds.

Are files sent through BatChat encrypted?

Yes. All file transfers use BatChat’s end-to-end encryption (RSA key exchange, asymmetric encryption, Double Ratchet protocol). Files are encrypted on the sender’s device and decrypted only on the recipient’s device.

Can I preview Office documents directly in BatChat without downloading?

Yes. Since the v2.5.0 update, BatChat supports online preview for Word documents, Excel spreadsheets, PowerPoint presentations, and PDF files. You can view these files within the chat interface without switching to another application.

Can I send files in BatChat group chats?

Yes. File transfer works in group chats with the same features as one-on-one chats, including breakpoint resume and end-to-end encryption. Group members download shared files on demand rather than automatically.