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A payment QR code is a way to carry an instruction, not proof that the destination is trustworthy or that a payment has happened. We ran the same 20 inputs through two URI parsing implementations. They did not handle every input the same way. We also generated two SVG QR examples and independently decoded their exact contents.
For a payment, the useful information is usually a destination , an optional amount and an optional note. The square pattern does not add a signature or make those fields authoritative. A scanner can read the pattern perfectly while the rejects the destination—or while an application still needs to reject an invalid amount.
Study release 2026-09-30.1. This is a parser and digital QR round-trip study, not a phone-camera or full wallet-app compatibility test. The hero is an AI-generated abstract illustration and is not a functional payment code.
This deliberately invalid destination makes the example safe to inspect without creating a payable request. In a real invoice, replace it with a receiving address obtained from the intended wallet. The amount is expressed in LTC: 0.125 means one eighth of a Litecoin. It does not mean €0.125, $0.125 or 0.125 .
The address in this diagram is intentionally invalid. The label is a note, not a verified merchant name, and the URI is not a receipt.
Common fields and what they do not establish
Field
What it communicates
What it does not prove
litecoin:
Which currency handler should open the request.
That the destination belongs to the expected person.
Destination address
Where the transaction should create an output.
Who controls the keys or whether the address was substituted.
amount
Requested quantity in LTC.
The fiat value, miner fee or amount already received.
label / message
Optional human-readable context.
An authenticated identity or an on-chain invoice reference.
Optional time / expiry fields
Application-specific metadata, if supported.
A consensus rule preventing payment after an invoice deadline.
The long-used -style format supplies the background for these fields. BIP21 is a Bitcoin specification and has been superseded there by BIP321; that status does not imply every Litecoin wallet implements the replacement. We checked Litecoin-specific source and pinned versions rather than assuming support from a standard’s name.
Two scan examples with different payloads
Both SVGs below contain the same invalid destination. The first carries only the address placeholder; the second adds an amount and label. A generic QR reader should be able to reveal the text, while a wallet must reject the destination. These are educational fixtures, not donation requests.
Address-only example: no amount is supplied. Open the SVG.Amount-and-label example: 0.125 LTC and Invoice 17, still with an invalid destination. Open the SVG.
The first symbol uses a 25-by-25 module grid and the second 33-by-33, excluding the four-module quiet zone. More data increased the symbol size in this controlled encoding. Both use error-correction level M. We decoded the generated module rasters with zxing-cpp and matched every character. That check does not measure how either code behaves on a damaged printout or a particular phone camera.
What the two parsers returned
We tested Electrum-LTC 4.2.2.1’s unchanged URI and address-validation functions in an isolated source harness, and the published bip21 3.0.0 JavaScript library configured for the Litecoin scheme. Electrum’s full application and GUI were not launched. The JavaScript library is a decoder, not a wallet; its README explicitly requires callers to check the address.
“Accepted” below means only that the tested function returned data. It does not mean a wallet would display, sign or broadcast the corresponding payment. The test corpus uses synthetic address hashes with no known ; they must never be funded.
Selected observations from the 20-input corpus — parsing stage only
Input
Electrum-LTC source functions
bip21 3.0.0 library
No amount
Address returned; amount absent.
Address returned; amount absent.
0.12345678 LTC
12,345,678 litoshis returned.
0.12345678 returned as a JS number.
0.123456789 LTC
Truncated to 12,345,678 litoshis.
Nine-decimal numeric value retained.
Negative amount: −1
Negative integer returned by this function.
Rejected.
Decimal comma: 0,125
Rejected.
Rejected.
Duplicate amount=1&amount=2
Rejected.
Rejected.
Wrong address checksum
Rejected by the address check.
Address text returned; caller must validate it.
Unknown req-invoice field
Returned as a field.
Returned as a field.
Encoded Café & invoice 17
Full label recovered.
Full label recovered.
Empty amount=
Amount absent.
Empty string retained.
The ninth decimal is a useful example of why a successful decode is not sufficient validation. One implementation reduced the precision; the other preserved a value that still needs conversion to Litecoin’s indivisible unit. Applications should reject an unsupported precision deliberately rather than silently turn a customer’s instruction into a different value.
The negative-amount observation is also confined to the parsing stage. It does not demonstrate that Electrum-LTC can send a negative payment. A wallet has later checks when constructing and approving a transaction. We include the returned value because developers need to know where validation actually occurs, not because a parser result proves an exploitable wallet defect.
An unfamiliar field can be lost or ignored
An ordinary optional query parameter may be ignored by software that does not understand it. The historical BIP21 convention gives fields beginning req- a different meaning: an implementation that does not understand them should reject the request. Both tested parsing functions returned our synthetic req-invoice field. That result leaves any enforcement to another layer and is not evidence that the invoice requirement was honored.
We separately read Litecoin Core 0.21.5.8’s GUI URI parser: its unknown-required-field branch returns failure. This is a source inspection, not a Core GUI scan test, and therefore is not presented as another measured wallet result.
A merchant should keep their invoice requirements in the checkout system and verify the actual payment against them. Adding invoice=17 to a URI does not guarantee that every wallet preserves it or writes it into the . Standard address-and-amount outputs do not carry the URI’s label as an message.
Spaces, ampersands and decimal separators
URI query strings use & to separate fields. In our malformed-label case, the unescaped text label=Cafe & invoice 17 was not recovered as one complete label by either implementation. Encoding the intended ampersand as %26 and the space as %20 preserved the text. UTF-8 percent encoding also preserved the accented character in Café.
For a request generator, build the query with an encoding library rather than concatenating raw customer text. Use a plain decimal point for LTC amounts, up to eight decimal places, and integer litoshis internally where practical. Our test parsers accepted scientific notation, but that observation is not a reason to emit it: ordinary decimal notation avoids relying on permissive behavior outside the basic amount grammar.
The Litecoin.watch payment request tool checks supported Litecoin addresses and uses a strict amount input before constructing the URI. Its fields are deliberately narrower than every possible extension. It is a request generator, not a universal URI importer or a substitute for the receiving wallet’s own review.
An expired invoice can still receive coins
A QR code does not control the blockchain. In our fixture with time=1&exp=1, both parsers returned metadata; neither parsing call proved or enforced a business deadline. A checkout can stop displaying an expired request, but an old screenshot can still contain a valid destination.
Handle late payments as invoice exceptions. Record the amount, observation time, and agreed -rate policy, then decide whether to honor, supplement or refund the payment. The refund and underpayment guide gives a practical record to keep. A label or expiry field is not an on-chain cancellation mechanism.
Before approving a scanned payment
Check the destination through the trusted checkout or recipient. A valid checksum catches certain transcription errors, not a malicious replacement with another valid address.
Read the amount and unit. Confirm LTC and the decimal placement. If the request supplied no amount, enter it from the agreed invoice rather than guessing.
Review the fee and total separately. The requested recipient amount and the wallet’s are different parts of the transaction.
Treat the label as unverified text. Avoid personal or confidential information in a request that can be photographed or logged.
After sending, verify the output and status. Use your wallet record and, if appropriate, the transaction checker. A QR image is never the receipt.
Download the corpus and reproduce the observations
The Python harness extracts selected function definitions without changing their bodies, uses the upstream Base58Check and validators, records source hashes, and omits unrelated wallet startup and cryptographic signing dependencies. It is a reproducible source-function experiment, not execution of the complete Electrum release. The JavaScript run uses a pinned package and lockfile. The package also explains how to regenerate the two safe QR symbols.
No , wallet file, real payment, operating-system URI handler, mobile app, camera, printed code, signed payment request or MWEB address was tested. These boundaries matter: the useful finding is that each layer—QR decoding, URI parsing, destination validation and payment approval—must be checked on its own.
Litecoin (LTC)
In brief A peer-to-peer cryptocurrency with its own Scrypt proof-of-work network and a maximum issuance of 84 million LTC.
A peer-to-peer cryptocurrency launched in 2011. Litecoin uses Scrypt proof of work, targets an average 2.5-minute block interval and has an issuance schedule capped at 84 million LTC. Individual block times and payment acceptance times vary.
For example Sending 0.1 LTC on Litecoin transfers a fraction of one coin; you do not need to buy a whole LTC first.
Common mistake Assuming a token with LTC in its name on another network is automatically native Litecoin.
In brief An encoded payment destination whose network, owner and wallet compatibility still need checking.
An encoded destination for a payment. Common transparent Litecoin addresses begin with L, M or ltc1; MWEB uses a different address format. An address is not a bank account or proof of identity. Check network and wallet compatibility before sending.
For example To receive LTC, copy a Litecoin receiving address from your wallet and check it against the address shown to the sender.
Common mistake A valid-looking address does not prove that it belongs to the intended person or uses the network the sender selected.
In brief Software or a device for managing wallet keys and payments, though a watch-only setup cannot sign on its own.
Software or a device that manages keys and helps you receive and send Litecoin. Coins are recorded on the blockchain. A watch-only wallet can show addresses and transactions without holding the keys needed to spend.
For example One wallet can generate several receiving addresses and still show them as a single combined balance.
Common mistake Thinking coins live inside the app, or that seeing a balance proves that the wallet can sign a spend.
In brief An informal name for 0.00000001 LTC, the smallest Litecoin unit, with 100,000,000 in one LTC.
An informal name for the smallest Litecoin unit: 0.00000001 LTC. One LTC contains 100,000,000 litoshis. Some software uses the inherited label satoshi, so always check which coin and unit a screen means.
For example 10,000 litoshis equal 0.0001 LTC; 1 litoshi equals 0.00000001 LTC.
Common mistake Confusing a fee quoted per virtual byte with that many litoshis for the whole transaction.
In brief Text, often encoded as a QR code, that requests a payment but does not send coins or prove the recipient's identity.
Structured request text, often inside a QR code, containing a destination and optional payment fields. Many Litecoin requests use the litecoin: scheme. Bitcoin's older BIP21 format provides background, but supported addresses, amounts and parameters depend on the actual Litecoin wallet.
For example The placeholder litecoin:ADDRESS?amount=0.1 requests 0.1 LTC; it does not send coins or prove that the named recipient controls the address.
Common mistake Assuming a QR code authenticates a merchant or that every wallet interprets optional fields and expiry information the same way.
In brief Secret data a wallet uses to sign spending; one key may cover only part of a wallet and must never be shared.
Secret data used to authorize spending under the conditions attached to coins. In a simple single-key wallet, anyone with that key can spend the coins it controls. A wallet may manage many keys; never share them.
For example A wallet signs a spend using a private key; the recipient only needs your payment, not that secret key.
Common mistake Sharing a key with support or assuming one exported key necessarily backs up every address in a wallet.
Compare: Seed phrase vs private key
Seed Phrase
Recovery words used by many wallets to rebuild key material; the correct format, optional recovery passphrase and wallet settings still matter.
Private Key
A secret used to authorize spending under its key conditions; one exported private key is not necessarily a backup of every key a wallet uses.
One example A fictional simple HD wallet can derive several receiving keys from one recovery setup; exporting just one of those private keys does not preserve the others.
Remember: Identify the complete backup method for the original wallet, keep secret recovery material offline and never paste it into this website.
In brief A linked record of transaction blocks that Litecoin nodes validate, choosing a valid chain by accumulated mining work.
A ledger of cryptographically linked blocks. Litecoin full nodes validate proposed blocks against consensus rules and select among valid chains by accumulated proof of work. Recent blocks can be reorganized, so confirmation depth matters.
For example A block explorer reads the chain so you can inspect where a transparent transaction was included.
Common mistake Assuming an explorer listing proves the sender's identity or that a recent block can never be replaced.
In brief Recorded in accepted blockchain blocks, unlike account changes a service may make only in its own records.
Recorded in the blockchain's accepted blocks. For transparent Litecoin, many transaction details are publicly visible, but an exchange's internal account changes need not create an on-chain transaction. Blockchain records alone do not establish an owner's identity or why funds moved.
For example A confirmed ordinary LTC payment appears in Litecoin blocks; an exchange moving balances between its own customer accounts may not.
Common mistake Assuming every account activity creates a blockchain transaction or that every large transfer is a trade.
In brief A transaction identifier for looking up outputs and confirmations, which alone does not prove that a payment arrived.
The identifier used to look up a transaction. For an ordinary transparent Litecoin transaction it is shown as a 64-character hexadecimal string. Use it to inspect the transaction's outputs and confirmations; the ID alone does not prove a payment is confirmed.
For example Copy the TXID from your wallet's payment details into a Litecoin explorer to check the recipient output and confirmation count.
Common mistake Sharing a seed phrase to trace a payment, or treating a screenshot or TXID alone as proof that the expected amount arrived.
In brief A service for trading currencies or assets, whose custodial account balance does not give you control of its private keys.
A platform or service for buying and selling cryptocurrencies against fiat currencies or other assets. Trading methods, custody, supported pairs and withdrawal rules vary by service. A balance on a custodial exchange is an account claim; it does not mean you control the wallet's private keys.
For example After buying LTC on a custodial exchange, you request a withdrawal if you want it sent to your own wallet.
Common mistake Assuming an account balance means you possess the private keys, or overlooking the selected withdrawal network.
In brief For ordinary transparent Litecoin transactions, the fee is total input value minus total output value, separate from a service withdrawal charge.
For an ordinary transparent Litecoin transaction, the network fee is the total input value minus all output values, including change. Wallets estimate it using transaction size and a fee rate, so sending more LTC does not automatically mean a higher fee. A service's withdrawal charge is a separate quote and may already cover network costs.
For example Fictional inputs total 1 LTC, while recipient and change outputs total 0.99999 LTC: the network fee is 0.00001 LTC.
Common mistake Confusing fee rate with total fee, leaving change out of output totals, or equating a service's withdrawal charge with the full network fee.
Compare: Network fee vs withdrawal fee
Transaction Fee
An ordinary transparent transaction's network fee is its total input value minus its total output value; transaction size and fee rate help determine the estimate.
Withdrawal Fee
A service sets its withdrawal charge under its own rules, and that charge can differ from the network fee on the transaction it broadcasts.
One example If a fictional service deducts a 0.001 LTC charge from a 1 LTC withdrawal, the recipient receives 0.999 LTC; these figures do not reveal the transaction's network fee.
Remember: Check the final account debit, recipient amount and minimum separately; add a network-fee estimate only if it is an additional charge, so the same cost is not counted twice.
In brief A transaction gains confirmations as blocks build on its inclusion, but those confirmations can fall if chain history changes.
A transaction receives its first confirmation when included in a block in the accepted chain. Each block then built on top adds another. A chain reorganization can reduce or remove the count. The recipient decides how many confirmations it requires. Litecoin targets an average 2.5-minute block interval; individual blocks can arrive sooner or much later.
For example A transaction in the latest accepted block has one confirmation; the next block raises that count to two.
Common mistake Confusing a wallet's sent message, a TXID or mempool visibility with the first confirmation.
In brief A transaction format and validation change that separates witness data and changes how block capacity is counted.
Segregated Witness: a change to transaction serialization and validation that separates witness data, fixes certain transaction-malleability issues and changes capacity accounting. Litecoin activated it in May 2017.
For example An ltc1q receiving address uses a SegWit format; the sender still needs to check that its service accepts that address.
Common mistake Assuming every wallet supports every address format, or that SegWit guarantees a fixed confirmation time.
In brief Secret recovery words that need the right wallet format, settings and any extra passphrase; keep them offline.
A sequence of secret recovery words that some wallets use to rebuild keys. Recovery must match the original wallet's word format, settings and any extra passphrase; other wallets use different backup methods. Keep the words offline and follow the original wallet's official recovery instructions.
For example In a BIP39 wallet, the same words with a different extra passphrase produce a different seed and can show different addresses.
Common mistake Entering recovery words into a website, sharing them with support or assuming every Litecoin wallet uses the same word format.
Compare: Seed phrase vs private key
Seed Phrase
Recovery words used by many wallets to rebuild key material; the correct format, optional recovery passphrase and wallet settings still matter.
Private Key
A secret used to authorize spending under its key conditions; one exported private key is not necessarily a backup of every key a wallet uses.
One example A fictional simple HD wallet can derive several receiving keys from one recovery setup; exporting just one of those private keys does not preserve the others.
Remember: Identify the complete backup method for the original wallet, keep secret recovery material offline and never paste it into this website.
Downloadable data or code · Source-function parser test.
Content review recorded: 2026-09-29. The review record does not identify a separate independent reviewer. An edited date above records an edit, not a new fact-check. AI-assisted editing or new artwork alone does not complete a source review.
Editor-in-chief of Litecoin.watch and founder of MyBank.pl. His published work covers foreign exchange, financial education and Litecoin. On Litecoin.watch, his remit includes editorial direction, source transparency and the practical guides and research published by the site.
