G
G5SIM vs Firefox Relay
Pricing, features, platforms and who each one suits — side by side.
5
Choose 5SIM if…
- you need an API to build on
- you're in its core audience: privacy-minded individuals, developers automating sign-ups
F
Choose Firefox Relay if…
- you want a free plan to start with
- you want open source you can self-host or audit
- you work on Chrome
- you're in its core audience: privacy-conscious individuals, firefox users
Side by side
Feature 5SIM Firefox Relay
Pricing modelPaidFreemium
Starting price—$0.99/mo
Free plan
Free trial
API
Open source
PlatformsWeb, APIWeb, Chrome
CategorySMS verification servicesEmail & phone aliases
Company—Mozilla
Full feature lists
5 5SIM
- Temporary virtual numbers for SMS receiving
- Numbers from 150+ countries
- Supports 1100+ services, including Telegram and WhatsApp
- Pricing set per country and operator
- API key from the account menu
- Works with the SMS-activate API format
- Referral program
F Firefox Relay
- Random email masks that forward to your real inbox
- Masked phone number that forwards calls and texts
- Removal of email trackers from forwarded mail
- Blocking of promotional emails while keeping receipts
- Personal mozmail.com subdomain for instant masks
- Anonymous replies to emails and texts
- Dashboard to label, create and block masks
- Browser extension for creating masks on any site
What you'd pay
The cheapest plan that fits, per month, billed yearly where the plan offers it.
5SIM
Pay per numberFrom $0.008 per number
Firefox Relay
Limited email protectionFree
Email protection$1.99/mo or $0.99/mo billed yearly ($11.88/yr)
Email & phone protection$4.99/mo or $3.99/mo billed yearly ($47.88/yr)
Add VPN protection$6.99/mo billed yearly ($83.88/yr)
Strengths and limitations
5SIM
- Prices start from $0.008 per number
- Large coverage: 150+ countries and 1100+ services
- Compatible with the SMS-activate API format
- Prices vary by country and operator, with no flat rate
- Numbers are temporary, meant for receiving codes
Firefox Relay
- Free tier includes 5 email masks and tracker removal
- Source code is public on GitHub
- Combines email and phone masking in one service
- Browser extension rated 4.1/5 from over 1,250 reviews
- Free plan is limited to 5 email masks
- Premium tiers are waitlist-only
- Premium is available only in certain countries
- Not recommended for identity-verified emails or ones that need attachments
More comparisons
Other options to consider
GG
Paid
G
Pay-per-use virtual numbers for receiving SMS verification codes
SMS verification servicesAPI
S
SS
Paid
S
Temporary and rental phone numbers from 60+ countries for SMS verification
SMS verification servicesAPI
H
HH
From $6.99/mo
H
Second and temporary phone numbers for private calls and texts over Wi-Fi
Virtual phone numbers
C
CEmail and phone aliases, data broker removal and spam call blocking for consumers
From $9.99/mo
C
From $9.99/mo
C
Email and phone aliases, data broker removal and spam call blocking for consumers
Email & phone aliases
S
SS
Free, from $3/mo
S
Open-source email aliases to hide your real address and block spam
Email & phone aliasesFree planAPIOpen source
A
AOpen-source email aliases that forward to your inbox and hide your real address
Free, from $1/mo
A
Free, from $1/mo
A
Open-source email aliases that forward to your inbox and hide your real address
Email & phone aliasesFree planAPIOpen source
Facts from each vendor's public pages, prices checked Nov 8, 2026. Editorial policy