Module 3 · Lesson 23 of 45

Stuck or pending transactions

⏱ 5 min read ● Intermediate Module 3 · Fees & mechanics

Sometimes a transaction neither succeeds nor fails — it just sits there, "pending", occasionally for ages. It's unsettling, but it's usually fixable from your wallet.

Why it hangs

When you submit a transaction it enters the mempool, a waiting room of pending transactions. Validators pick the most profitable ones first, so if your priority fee is too low relative to current demand, yours can wait — sometimes for hours.

The nonce: why order matters

Each account's transactions are numbered by a nonce, and they must process in order. If transaction #5 is stuck, #6 and #7 can't go through behind it, even if you paid them more. That's why one stuck transaction can seem to freeze your whole wallet — clearing #5 unblocks the queue.

Your two tools: speed up and cancel

Most wallets let you replace a pending transaction by resubmitting it at the same nonce with a higher fee:

  • Speed up — rebroadcast the same transaction with a higher priority fee so validators pick it up.
  • Cancel — replace it with a $0 transaction to yourself at the same nonce and a higher fee, voiding the original.

Both work by out-bidding the stuck transaction at its own nonce; whichever the network confirms first wins.

Practical guidance

  1. Don't blindly submit a brand-new trade to "try again" — that creates a second transaction at the next nonce, not a replacement.
  2. Use the wallet's own speed-up or cancel button so the nonce is reused correctly.
  3. If the network is deeply congested, the calmest move is sometimes just to wait.

This is far more of an Ethereum-mainnet concern than an L2 or Solana one, where fast finality means pending transactions rarely linger.

Key terms
PendingA submitted transaction not yet confirmed on-chain.
MempoolThe pool of pending transactions validators choose from.
NonceThe sequence number that forces an account's transactions to process in order.
Replace-by-feeResubmitting at the same nonce with a higher fee to speed up or cancel.
!Common mistakes
  • Submitting a fresh trade to 'try again' while the first is still pending, creating a second transaction.
  • Setting the priority fee very low during congestion, then wondering why it's stuck.
  • Forgetting that one stuck low-nonce transaction blocks everything queued behind it.
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