The explosion of distributed ledger technology over the past decade has led to significant challenges in scalability and network performance. According to analysis from the team of experts at Tan Phat Digital, in the digital infrastructure context of 2026, the "pending" transaction status is not simply a technical issue but also a consequence of complex economic interactions between users and authenticating entities. A transaction is considered pending when it has been digitally signed and distributed to the network but has not been immutably recorded in the block. This delay often creates opportunity cost risks, especially in decentralized finance (DeFi) activities and highly volatile asset transactions.
The Mempool's operating mechanism and the technical origin of the delay
To understand why a transaction can be suspended for a long time, it is necessary to deeply analyze the structure of the Mempool (Memory Pool) - temporary storage area time for unconfirmed transactions. The mempool is not a single centralized entity but a collection of volatile databases that exist in the RAM of each node across the network. When a user makes a transaction, the message spreads through the gossip protocol, where each node checks the transaction's validity before adding it to its private mempool.
Economic Motives and Queue Priority
Validating entities (miners in PoW or validators in PoS) act as profit-optimizing economic agents. They scan the mempool to select the highest reward transactions to include in the next block. Because each network's block size or gas limit is limited, a silent auction of transaction fees takes place continuously.
Operating characteristics of popular networks:
Bitcoin (Layer 1): Average block generation time around 10 minutes with low throughput (~7 TPS). Uses the standard Mempool mechanism with a default limit of about 300 MB.
Ethereum (Layer 1): Block creation time is about 12 seconds, throughput is 20-30 TPS. Uses EIP-1559 Mempool mechanism and dynamic gas limit.
Solana (Layer 1): Extremely fast with block creation time under 1 second and throughput over 65,000 TPS. Uses Gulfstream (Pipelined) mechanism instead of traditional Mempool.
Layer 2 (L2): Almost instant confirmation time, throughput over 40,000 TPS thanks to Sequencer Batching mechanism and local buffering.
If the transaction fee is set too low compared to the market level, that transaction will be pushed to the bottom of the queue. During periods of extreme network congestion, the mempool can become full, forcing nodes to implement an eviction policy, eliminating transactions with the lowest fees to make room for new transactions with higher fees. This explains why some transactions can disappear from block explorers after a long period of being unconfirmed.
See also: Gas What are Limit and Gas Price? How to optimize Ethereum transaction fees in 2026
In-depth analysis of the causes of transaction suspension in the 2026 era
By 2026, although scaling solutions have developed strongly, Tan Phat Digital finds that delays still occur due to a combination of many factors from economics, technology to user behavior.
Market fluctuations Fee field and mechanism EIP-1559
On the Ethereum network and EVM compatible chains, the fee mechanism includes base fee (Base Fee) and priority fee (Priority Fee). The base fee is automatically adjusted based on the demand of the previous block. If a user sets a Max Fee lower than the current base fee, the transaction will never be included in the block until the base fee is reduced. During hot market events, priority fees can skyrocket from normal levels to tens of Gwei in a matter of seconds, rendering old transactions obsolete.
Network congestion and information spikes
Congestion occurs when the number of new transactions exceeds the processing capacity of blocks. The year 2026 will witness many new causes:
- zone slows down block propagation and validation.
Configuration errors and transaction sequence (Nonce) issues
A common technical error on EVM chains is the Nonce index. Transactions must be performed in correct ascending order. If a low Nonce transaction gets stuck due to low fees, all subsequent higher Nonce transactions will be suspended indefinitely until the first transaction is processed.
Technical Solution for Fast Pending Transaction Processing
Users have a variety of tools to intervene in stuck transactions, depending on the blockchain type and their role.
Accelerate Transactions Using the Method Replace-by-Fee (RBF)
RBF allows the sender to replace a pending transaction with a new transaction with a higher fee but the same input parameters. Most modern wallets in 2026 such as MetaMask or Trust Wallet integrate a "Speed Up" button to automate this process.
Recipient solution: Child-Pays-For-Parent (CPFP)
CPFP allows the recipient to speed up confirmations by creating a "child transaction" using pending funds with extremely high fees, forcing the validator to process both the parent transaction to receive the reward from the child transaction.
Detailed comparison of RBF and CPFP:
On the execution side: RBF is performed by the sender, while CPFP is for the receiver.
Supporting network: RBF is popular on Bitcoin and EVM chains; CPFP is strongest on Bitcoin (especially SegWit).
Configuration requirements: RBF usually needs to be enabled before sending, CPFP requires no prior configuration.
Complexity and cost: RBF has low complexity and is more economical; CPFP is more complicated and expensive due to having to pay fees for two transactions.
Cancel a transaction using the custom Nonce overwrite method
At Tan Phat Digital, we often guide users to use the "Custom Nonce" technique to cancel orders on MetaMask:
Enable "Customize transaction nonce" in advanced settings high.
Record the Nonce number of the stuck transaction.
Send 0 ETH to your own wallet address with that Nonce number.
Set the highest Gas fee (Aggressive) to overwrite the old transaction.
See more: Learn all about Gas Fee and calculation units in Ethereum
Infrastructure vision 2026: Layer 2 and protocol upgrades
The blockchain ecosystem in 2026 has made great strides to completely resolve transaction hangups.
Layer 2 (Arbitrum, Optimism, zkSync): Process off-chain transactions with almost instant confirmation speed (soft finality) and 10-50 times lower cost than Mainnet.
Upgrade Glamsterdam and Hegota on Ethereum: Improve execution efficiency, separate people proposal-builder (PBS) and minimizes the risk of transactions getting stuck due to fee estimation errors.
Security and fraud prevention when handling stuck transactions
When transactions get stuck, users easily fall into the trap of cybercriminals. Tan Phat Digital advises you to be wary of:
Fake technical support: Fraud bots that request Seed Phrase to "synchronize wallets".
Gas Honeypots: Websites that promise to speed up transactions but actually contain withdrawal malware.
Address Poisoning: Attackers send small transactions with addresses Similar to the user's address to trick them into copying it by mistake when executing the Speed Up command.
List of risks and prevention measures:
Phishing Website: Identification through URL with wrong characters. Take precautions by always accessing from official bookmarks.
Spoofing support: Identify when private key is requested. Prevention by absolutely not sharing Seed Phrase.
Malicious approval: Identification through "Approve All" permission request. Prevent by using tools like Revoke.cash.
SIM Swap: Identify when mobile signal is lost. Prevent by using Authenticator App instead of SMS OTP.
Comparing the effectiveness of processing methods in 2026
Below is a summary of processing options by priority:
Wait naturally: Cost $0. Suitable for non-urgent transactions when network fees are trending down. Highest safety.
Speed Up (RBF): Additional cost of 10-30% of initial fee. Effective immediately in the next block. Is the top priority choice for senders.
Cancel (Overwrite): Cost is equivalent to a new transaction with high Gas. Instant effect. Used when you want to stop a wrong order or quickly recover capital.
CPFP: Costs are often high because you have to pay for new transactions. Used when you are the recipient or the wallet does not support RBF.
Accelerator (Accelerator Service): Cost $5 - $20. Depends on the hashrate of the mining pool. Used when Bitcoin transactions are stuck in the mempool for too long.
10 Practical Case Studies on handling stuck transactions (Updated 2026)
Below are 10 typical cases compiled by Tan Phat Digital to illustrate transaction processing challenges and solutions:
Gas Mint NFT War Otherside (Yuga Labs): In May 2022, a sale of 55,000 NFTs caused Ethereum gas fees to spike to 8,000 Gwei. Users pay between $4,000 and $10,000 in gas for each $6,000 NFT. This is a classic example of "fee auctions" in the public mempool causing normal transactions to get stuck for hours.
Doodles NFT Public Sale Incident: During the Doodles sale, the number of failed transactions in a single block reached a record 1,017 transactions. Those who set fees lower than the "Aggressive" level were stuck and were eventually pushed out of the queue by the network when the NFTs ran out.
Depositing Ethereum to Kraken (2025): Users depositing ETH via the zkSync Era network encountered a situation where the funds did not show up in their accounts. The reason is because this network is in the alpha stage and the floor needs longer confirmation time than usual. The solution is to contact TXID support for manual intervention.
Rescuing Bitcoin from the exchange using CPFP: An investor withdraws BTC from the exchange but the exchange sets the fee too low (10 sats/vB). Because it is a transaction from an exchange wallet, users cannot use RBF. They used an Electrum wallet connected to the Ledger to create a "child" transaction that spent that pending amount for a fee of 150 sats/vB, getting both transactions confirmed in the next block.
Fast Withdrawals from Arbitrum via Fast Withdrawals: Instead of waiting 7 days for the usual fraud proof mechanism, a DeFi dApp used the "Fast" mechanism Withdrawals" (with confirmation from a committee of validators) to help users reclaim assets on Layer 1 in just 15 minutes.
zkSync transactions stuck in "Sending" state: Due to a block reorg issue on the Holesky testnet (Layer 1), transactions on Layer 2 zkSync were stuck in "sending" state for days. The technical team must rollback the database state and resend batches of transactions for processing.
Address Poisoning attack during Speed Up: A user in a hurry to speed up a pending transaction mistakenly copied the address from the transaction history (which was "poisoned" by the scammer with an address with identical beginning and ending). As a result, the accelerated amount is sent directly to the hacker's wallet. Lesson: Always double-check each character before signing a replacement command.
Network congestion due to order insertion by MEV Bots: During an ETH price fluctuation in late 2025, MEV bots scanned the mempool and inserted priority orders with fees above 50 Gwei to conduct arbitrage, causing normal remittance transactions of individual users (15-20 Gwei set fees) to be suspended for 12 hours.
Ethereum during network congestion: On a peak day at the end of 2025, the amount of Base Fee burned reached 9 million USD, surpassing the amount of newly issued ETH. This proves that even though user transactions are slow, Ethereum's economic system becomes more "scarce" thanks to the EIP-1559 mechanism.
Frequently Asked Questions (FAQ)
Below is a summary of the 10 most common questions that Tan Phat Digital has answered for users related to frozen transactions:
Why is my transaction suspended?The main reason is that the fee-per-byte you set is lower than the required level by validating entities (miners/validators) during periods of network congestion.
How long can a pending transaction last? Usually from a few minutes to a few hours, but if the fee is too low, it can stay in the mempool for days or even weeks until it is automatically deleted by the system cancel.
Can I cancel a confirmed transaction? No. Once a transaction has been written to the block and received the necessary number of confirmations, it becomes immutable and irreversible on the blockchain.
When should I use the Speed Up (RBF) feature? You should use RBF when you need the transaction to be processed immediately (like when swapping on a DEX or making a rush payment) and your wallet has already enabled this feature before sending.
What I have to do What if the wallet does not support acceleration (RBF)? If you are the recipient or the sender's wallet does not support RBF, use the CPFP (Child-Pays-for-Parent) technique by creating a child transaction with high fees from the pending balance.
Are transaction acceleration services from third parties (Accelerators) safe? Services from large mining pools are usually safe completely, but you should absolutely never provide a private key or seed phrase for these services.
Why should I not make new transactions when there is an old order pending? This creates a "waterfall" effect, causing later transactions to be blocked by old transactions with a lower Nonce index, leading to the entire chain of transactions being stuck.
Will my money be lost if the transaction is not confirmed? No. If the transaction is not confirmed after a long time (usually 14 days for Bitcoin), the nodes delete it from the mempool and the actual balance remains in the sender's wallet.
Why are Ethereum gas fees still high in 2026? Because the demand to use the main network (Layer 1) for complex DeFi operations and data storage from Layer 2 is still very large, exceeding the limited block space
How to professionally avoid transaction jams? Tan Phat Digital recommends that you always use real-time fee forecasting tools, enable the RBF feature in your wallet, and prioritize performing daily transactions on Layer 2 networks.
Long pending transactions in the 2026 era are no longer an unsolvable problem. By mastering techniques such as RBF, CPFP and Nonce mechanism, users can fully proactively manage their assets. The shift to Layer 2 networks is also a sustainable solution to completely eliminate delays. Tan Phat Digital always recommends that users maintain high vigilance, use hardware wallets and transaction simulation tools to ensure absolute safety in all technical operations.
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