How these two SMS verification services compare on features and reliability.
OnlineSim (onlinesim.io) is a virtual phone number service operating since 2013 that provides both free shared numbers and paid private numbers for SMS verification. It uses its own physical SIM card infrastructure across 90+ countries. While OnlineSim offers some of the lowest per-SMS pricing in the market (from $0.05), its free shared numbers are notoriously unreliable since they are used by thousands of people simultaneously. The service also cannot receive SMS from banks or financial institutions.
| Feature | Quackr | OnlineSim |
|---|---|---|
| Pricing | Free numbers + paid from ~$3 | From $0.05 per SMS |
| Countries | 15+ countries | 90+ countries |
| Number Type | Real carrier (non-VoIP) | Virtual/SIM-based |
| Free Numbers Reliability | Reliable, regularly updated | Unreliable, overused shared numbers |
| Bank/Financial SMS | Supported | Not supported |
| Registration Required | No (free numbers) | Yes (for paid), No (shared) |
| Customer Support | 24/7 live chat | Limited, slow response |
| API + AI Integration | REST API + MCP server | REST API only |
Shared Free Numbers Are Unreliable
OnlineSim's free public numbers are shared by thousands of users simultaneously. These numbers are frequently blacklisted by platforms, making verification attempts fail repeatedly. The numbers are also overused, meaning they may already be registered on the service you're trying to verify with.
Cannot Receive Bank or Financial SMS
OnlineSim explicitly states that their numbers cannot receive SMS from banks, payment systems, financial institutions, or government services. This is a significant limitation for users who need to verify banking or financial accounts.
Poor Customer Support
User reviews consistently mention slow or unresponsive customer support. When verification issues arise, getting help can be difficult and time-consuming.
Inconsistent Number Availability
Number availability on OnlineSim can be unpredictable. Popular services and countries frequently run out of stock, and SMS delivery delays are commonly reported by users.
Quackr provides real, non-VoIP phone numbers trusted by over 2 million users worldwide. Whether you need a free temporary number for a quick verification or a private number for long-term use, Quackr delivers reliability, global coverage, and flexible payment options.
Quackr's free numbers are regularly updated and actually work for verification. Unlike OnlineSim's shared numbers that are overused and blacklisted, Quackr maintains quality across its free number inventory.
Quackr's real carrier numbers can receive SMS from banks, payment platforms, and financial institutions — something OnlineSim explicitly does not support.
Get help whenever you need it with Quackr's round-the-clock live chat support. No waiting days for email responses like with OnlineSim.
Quackr provides reliable number availability and fast SMS delivery. No stock issues, no unexpected delays — just numbers that work when you need them.
Temporary phone numbers aren't just for tech-savvy users — millions of people rely on them every day to stay private, save money, and avoid spam.
Sign up for apps and websites without handing over your real phone number. Use a temporary number to receive the verification code, then move on — no strings attached.
Tired of promotional texts after signing up for a free trial? Use a disposable number so your real inbox stays clean and spam-free.
Buying or selling on Craigslist, Facebook Marketplace, or similar platforms? Use a temporary number to communicate with strangers without revealing your personal line.
Need a local number while traveling abroad? Get a temporary number from 15+ countries to access local services, register for apps, or receive important codes without roaming fees.
Keep your personal number private when setting up dating profiles or new social media accounts. If things don't work out, there's no trace back to your real number.
Building an app that requires SMS verification? Use Quackr's API and MCP server to automate testing with real phone numbers — no personal numbers needed.