Unconfirmed transactions are a common occurrence in blockchain networks. Let’s examine what this status means, how transactions are processed, why confirmation may be delayed or end in an error, and what to do if the wait time becomes too long.
What is meant by unconfirmed transactions
Before a transaction is permanently recorded on the blockchain, it must be verified and receive confirmations from network participants — miners* or validators*.
* Miners are participants in blockchain networks operating under the Proof-of-Work consensus mechanism. Using computational power, they verify the validity of transactions, group them into blocks, and compete with each other for the right to add a new block to the blockchain. As an incentive, miners receive rewards in the form of newly issued cryptocurrency and transaction fees.
* Validators are participants in blockchain networks operating under Proof-of-Stake consensus and its variations. They confirm transactions and create new blocks by locking (staking) their own funds in the network. The larger the stake and the higher the validator’s reputation, the greater the probability of participating in block creation.
An unconfirmed transaction has already been broadcast to the network but has not yet been included in a block or written to the blockchain. To do this, it must receive a certain number of confirmations — a process known as validation.
How the transaction confirmation mechanism works
To understand the nature of unconfirmed transactions, it is essential to examine the lifecycle of crypto transactions.
Transaction submission. The user initiates a transaction and signs it with their private key. This may be a cryptocurrency transfer, a token swap, interaction with a smart contract, or adding funds to a DeFi protocol.
Entering the mempool. After submission, the transaction is broadcast to the network and placed in the mempool — a queue of unconfirmed transactions awaiting processing.
Verification by network nodes. Miners or validators analyze transactions according to several criteria:
Whether the sender has sufficient funds;
Whether the fee matches the current network load;
Whether the cryptographic signature is valid.
Processing priority. Transactions are not processed strictly in the order they are sent, but according to the fee size. The higher the fee, the faster the transaction is included in a block. If the cost is too low, the transaction may remain in the mempool for a long time, especially during periods of high network congestion.
Confirmation and recording on the blockchain. After receiving the required number of confirmations, the transaction is included in a block and becomes irreversible — it can no longer be changed or canceled.
Why unconfirmed transactions may take a long time to process
1. Network congestion
Thousands of transactions may be in the mempool simultaneously. When user activity increases, waiting times grow. For example, on the Bitcoin network, during heavy load, the number of confirmations required can reach 20 or more.
At the same time, the average fee also increases and must be considered before sending a transaction. Current fees are conveniently tracked through blockchain explorers such as Blockchair, Blockchain.com, Etherscan, BNBScan, Solscan, Tronscan, TONScan, Arbiscan, Polygonscan, and similar services.
2. Fee too low
If a user sets a minimal fee, the transaction may take hours or even days to confirm. In such cases, it is acceptable to resend the same transaction with a higher cost.
The higher the fee, the higher the priority nodes assign to processing it. Acceleration is possible through wallet functions as well as with the help of third-party services.
On the Bitcoin network, this issue is especially typical for outdated Legacy addresses (starting with “1”). Modern formats — Native SegWit and Bech32 (bc1) — allow transactions to be sent faster and at lower cost.
3. Errors during transaction execution
Sometimes unconfirmed transactions end with an error. The most common reasons include:
insufficient gas* in networks using the Proof-of-Stake consensus mechanism;
errors in smart contracts;
failures or bugs in crypto wallets;
An incorrect Nonce* parameter in EVM networks.
* Gas is a conditional unit that measures the computational resources required to execute transactions in blockchain networks operating under Proof-of-Stake. Gas itself is not a fee: it determines how much computational work is needed, while the fee represents payment for that work in monetary terms. The amount of available gas determines whether an operation can be completed fully. If there is not enough gas, the transaction is interrupted, and the spent fee is not refunded, since network resources have already been used.
* Nonce is a sequential transaction number tied to the sender’s address in EVM-compatible blockchain networks (networks using the Ethereum Virtual Machine). The Nonce value ensures strict execution order and prevents transaction replay. Each new transaction from the same address must have a Nonce strictly following the previous one. If the Nonce parameter is specified incorrectly — for example, it does not match the expected following transaction number — the network rejects the operation or keeps it in an unconfirmed state until the discrepancy is resolved.
How to speed up an unconfirmed transaction
There are several ways to accelerate an unconfirmed transaction.
Crypto wallet features
Some crypto wallets support special mechanisms for speeding up unconfirmed transactions:
Replace-by-Fee (RBF) — a function that allows replacing a previously sent but not yet confirmed transaction with a new version that has a higher fee. Network nodes typically prioritize the updated transaction, since it becomes more economically attractive to include in a block.
Child Pays for Parent (CPFP) — an acceleration method in which the user creates a new transaction that depends on the previous unconfirmed one and specifies a higher fee for it. Miners or validators, aiming to receive a higher total reward, confirm both transactions simultaneously. This method is often used in the Electrum wallet.
* L2 protocols (Layer 2 solutions) are additional overlay technologies that operate on top of the base blockchain (Layer 1). They enable transactions to be executed off the leading network, with the final result settled on the base blockchain. This approach reduces the load on the leading network, significantly speeds up transaction processing, and lowers fees while maintaining the security level provided by the base blockchain.
Such solutions are especially suitable for fast transfers and micropayments, where it is essential to avoid long confirmation waiting times.
Transaction accelerators
If a transaction remains in the mempool for a long time, transaction accelerators can be used to speed it up. One such tool is PushTX by BestChange. PushTX is a transaction acceleration service that rebroadcasts unconfirmed operations to the blockchain network.
What PushTX does:
The service sends the unconfirmed transaction simultaneously to several reliable, widely used network nodes, thereby expanding its propagation in the mempool.
Through wider retransmission, the probability increases that the transaction will be noticed by miners or validators and included in a new block, even without changing the original fee.
The tool is especially effective for transactions that remain in the mempool for a long time due to temporary network failures, low node visibility, or unstable network load.
It is essential to consider that PushTX cannot forcibly speed up transaction processing and does not guarantee immediate confirmation. However, during periods of high load or when transactions become “stuck,” rebroadcasting significantly increases the likelihood that the operation will be included in a block.