Bitcoin Mining Pool Stratum URLs 2026: Ports, Usernames and What Rejected Shares Mean
A Stratum URL is the pool server address you type into your miner: a host name, a port and, for some pools, a protocol prefix such as stratum+tcp://. Take it only from the pool's own help page or your account, because addresses can change. Below are the settings of 10 pools as of 2026-10-23, what the sources say about ports 3333, 443 and 25, and what rejected shares mean.
POOL BTC is an independent comparison site for bitcoin mining pools. We are not a pool and we do not mine for you. This article is information, not advice. Addresses and ports can change, so check the pool's page before you point hardware at it. We used only primary pool pages, and every row shows where and when.
Stratum addresses, ports and usernames
The table lists what each pool publishes. Where two official sources disagree, both values are shown.
| Pool | Stratum address and ports | Username format | Source and date |
|---|---|---|---|
| ViaBTC, BTC Mining | stratum+tcp://btc.viabtc.io:3333 and :443 | userID.workerID, digits and lowercase, up to 64 characters; password optional | support.viabtc.com article 7207401012879, updated 2026-09-15 |
| ViaBTC, Smart Mining | bitcoin.viabtc.io:3333 and :443 | same | same page |
| AntPool | ss.antpool.com:3333, 443, 25 | subaccount.worker, any password such as 123 | AntPool help center, 2022-12-12 |
| AntPool, Bitmain page | stratum.antpool.com:3333, 443, 25 | subaccount.miner, empty password | support.bitmain.com article 360002287334 |
| F2Pool | btc.f2pool.com:1314, backups 25 and 3333; regional hosts btc-asia, btc-euro, btc-na, btc-africa, btc-latin .f2pool.com:1314; SSL stratum+ssl://btcssl.f2pool.com:1300 | account.worker, any password | F2Pool guide, 2025-11-13 |
| Braiins Pool | stratum+tcp://stratum.braiins.com:3333 and :443 | user.worker, any or empty password | academy.braiins.com, undated |
| EMCD | gate, eu, kz, cn, us .emcd.network:3333, also 3339 and 443; TLS eu and us .emcd.network:13339 | login.worker, password may be empty | help.emcd.io, 2026-09-22 |
| Luxor | stratum+tcp://btc.global.luxor.tech:700 | Subaccount.Worker, password 123 | docs.luxor.tech, undated |
| Binance Pool | bs.poolbinance.com, ports 8888, 3333, 1800, 443 | MiningAccount.Worker, password optional | Binance support FAQ 360041370811, 2025-12-17 |
| Trustpool | btc.trustpool.cc:3333, 443, 25 | Username.Worker, any password | trustpool.cc stratums PDF, undated |
| Kryptex Pool | port 7014; hosts btc, btc-eu, btc-us, btc-br, btc-sg, btc-hk, btc-ru, btc-ae .kryptex.network | WALLET.WORKER, password x or empty | pool.kryptex.com/btc, guide 2026-03-26 |
| OCEAN | stratum+tcp://mine.ocean.xyz:3334; DATUM gateway port 23334, self-hosted | BTC address, optionally .worker, password x | ocean.xyz/getstarted, 2023-11-28 |
Two conflicts are worth knowing. For AntPool, the old gitbook help center names btc.antpool.com:3333, 443 and 25, while the help center article of 2022-12-12 names ss.antpool.com. The Bitmain page names stratum.antpool.com. For F2Pool, the guide of 2025-11-13 puts btc.f2pool.com:1314 first, but the pool-info page lists btc.f2pool.com:3333 as the primary. Use whatever your account page shows.
Promminer, Neopool and Foundry USA show their addresses only inside the account, or in third-party sources we do not rely on, so we do not publish them.
To compare the pools themselves, see the pool list. To estimate income, use the calculator.
Why ports 3333, 443 and 25
Many pools list several ports for one host. The sources give only a short explanation. Some providers block port 3333. The old AntPool FAQ advises trying 443 if 3333 does not connect, and then 25. In the table, AntPool, Braiins, ViaBTC and Trustpool list 3333 and 443, and AntPool and Trustpool also list 25.
We did not find an official explanation of why 443 and 25 pass where 3333 does not, so we do not add one. Not every pool offers the same fallback ports: F2Pool uses 1314 with 25 and 3333 as backups, Luxor uses 700 and Kryptex uses 7014. Always use the ports from your own pool's page.
ViaBTC: bitcoin.viabtc.io:3333 vs btc.viabtc.io:3333
Both are ViaBTC addresses on the same support page, updated 2026-09-15. The difference is the mining mode. btc.viabtc.io:3333 is for BTC Mining. bitcoin.viabtc.io:3333 is for Smart Mining. Port 443 works on both hosts. The username format is the same: userID.workerID.
This is the address that appears in searches that lead to our site, so it is the one readers most need to identify. If you are not sure which mode your account uses, read the ViaBTC page or your account before you switch hosts. Our ViaBTC review covers the pool itself.
Accepted and rejected shares
A share is a piece of work your miner sends to the pool. In Stratum v1 the pool answers each submission through mining.submit with true for accepted and false for rejected, sometimes with an error (Bitcoin Wiki, Stratum mining protocol). We found no official list of error codes.
AntPool describes rejected shares as hashrate the miner could not deliver to the pool because of network fluctuations. A stale share, per a Bitmain search excerpt, is work submitted for a block that was already solved.
What is a normal rate? Two official AntPool sources disagree.
| Source | Normal reject rate |
|---|---|
| AntPool help center article "What is a normal rejection rate" | less than 1% |
| Old AntPool FAQ on gitbook | below 0.3% |
The old FAQ also gives a formula: (expired + repeated + other) divided by (received + expired + repeated + other). We show both numbers because we cannot tell which is current.
If the rate is higher, AntPool suggests restarting miners and checking the router or switch. For a single miner, check the cable and the port. Bitmain (support article of 2022-03-28) says the cause is usually an unstable network: your local network, your ISP or the pool server. It adds that if the miner's hashrate is fine, the rate can be ignored.
What we could not confirm: whether a rejected share changes your payout, how the AntPool dashboard labels accepted, rejected and stale shares, and any official list of rejection reasons. Do not assume an answer to any of these.
For the pool behind these numbers see our AntPool review, and for other pools in the table see Braiins and EMCD.
Stratum V2 on Braiins
Braiins Pool lists a Stratum V2 address next to the usual one: stratum2+tcp://stratum.braiins.com, with default port 3336. Per the Braiins page it needs Braiins OS. That is all we confirmed. For background on the protocol, see our articles on Stratum V2 and the follow-up, and the Braiins review.
FAQ
What is bitcoin.viabtc.io:3333?
It is a ViaBTC Stratum address for Smart Mining, with port 443 as an alternative. btc.viabtc.io:3333 is the BTC Mining address. Source: the ViaBTC support page updated 2026-09-15.
What is a pool server for bitcoin?
It is the address and port you enter in your miner's pool settings, for example stratum+tcp://btc.viabtc.io:3333. Your miner sends shares there. Take the address from the pool's own help page.
What is a normal reject rate?
AntPool's help center says less than 1%. An old AntPool FAQ says below 0.3%. The two official sources disagree. Bitmain says that if your hashrate is fine, the rate can be ignored.
Which port should I use if 3333 is blocked?
Some providers block 3333. The old AntPool FAQ advises 443 first, then 25. Use only ports your pool lists for its host.
What username format do pools use?
Mostly account.worker, such as userID.workerID at ViaBTC, subaccount.worker at AntPool and login.worker at EMCD. Kryptex uses WALLET.WORKER and OCEAN uses your BTC address, optionally with .worker.
Bottom line
Stratum settings come from the pool: host, port and username format. Where sources conflict, as with AntPool hosts, F2Pool ports and the normal reject rate, check your account page first. This article is information, not advice, and addresses can change, so check the pool's page.
Sources, checked 2026-10-23. Some AntPool and Bitmain help pages did not open in full for us, and their text is taken from search excerpts, so check the wording on the page itself:
- support.viabtc.com/hc/en-us/articles/7207401012879 (updated 2026-09-15)
- antpoolsupport-hc.zendesk.com (2022-12-12)
- antpoolsupport-hc.zendesk.com/hc/en-us/articles/5985343153305
- antpool.gitbooks.io/help-center/content/en/chapter-8/01.html
- support.bitmain.com/hc/en-us/articles/360002287334
- support.bitmain.com/hc/en-us/articles/5220664696473 (2022-03-28)
- f2pool.zendesk.com guide (2025-11-13)
- academy.braiins.com (undated)
- help.emcd.io (2026-09-22)
- docs.luxor.tech (undated)
- binance.com/en/support/faq/detail/360041370811 (2025-12-17)
- trustpool.cc/static/stratums_en.pdf (undated)
- pool.kryptex.com/btc (guide 2026-03-26)
- ocean.xyz/getstarted (2023-11-28)
- en.bitcoin.it/wiki/Stratum_mining_protocol
This article contains referral links to mining pools (marked as sponsored). We may receive a reward if you register through them. This does not change the figures or the order of rows in the tables: the terms are taken from the pools' official pages.