Zero-dependency parser and serializer for SPAYD (Short Payment Descriptor) QR-payment strings — read, write, encode/decode with single-file, copyable implementation and serialization support.
Zero-dependency Kotlin Multiplatform library for reading and writing SPAYD (Short Payment Descriptor) strings - the Czech pay-by-qr standard for bank transfers, a.k.a. QR Platba
The library is published to Maven Central.
implementation("tools.kmp:spayd:0.0.4") // check the latest version in Releases --->
Alternatively, you can simply copy the file spayd.kt into
your project!
Supports all Kotlin targets, all of them should be enabled. If there's a missing platform, please open an issue and it will get added.
The API is designed for consistency and discoverability. You are supposed to be able to search the API surface using
your IDE's autocompletion. As a rule of thumb, objects are constructed using factory functions, or with a Builder pattern.
Class Spayd is the entry point into the library. The rest of the API is discoverable with Spayd.<completion>
The library throws SpaydException : IllegalArgumentException from all decoding and encoding operations, and from
factory functions that fail to construct a valid object (e.g. Builder.build() with illegal configuration,
or Amount.fromString("Not a number")).
If you catch an exception that isn't a SpaydException, it's a bug. Please open an issue.
Spayd is not @Serializable to avoid the kotlinx.serialization dependency, but the following should do:
object SpaydSerializer : KSerializer<Spayd> {
// Configure the decoder and encoder to your needs
private val spaydDecoder = Spayd.Decoder.Builder().build()
spaydEncoder = Spayd.Encoder.Builder().build()
descriptor: SerialDescriptor = PrimitiveSerialDescriptor(, PrimitiveKind.STRING)
= encoder.encodeString(spaydEncoder.encode(value))
: Spayd = spaydDecoder.decode(decoder.decodeString())
}
val constructedSpayd: Spayd =
Spayd.Builder()
.account(IbanBic.fromCzAccount("721-77628031", "0710"))
.altAccount(IbanBic.fromCzAccount(CZBankAccount.fromString("721-77628031/0710")))
.altAccount(IbanBic.fromString("CZ4601000000192235210247"))
.amount(Amount.fromString("599.00"))
.currency(Currency.fromString("CZK"))
.message(Message.fromString("T-Mobile - QR platba"))
.recipient(Recipient.fromString("T-Mobile Czech Republic a.s."))
.vs(VS.fromString("1113334445"))
.ss(SS.fromString("11"))
.customAttribute(CustomAttribute.create("X-CUSTOM", "orang utan"))
.build()
// String received from an external source
val receivedSpayd =
"SPD*1.0*ACC:CZ5207100007210077628031*ALT-ACC:CZ5207100007210077628031,CZ4601000000192235210247*AM:599*CC:CZK*MSG:T-Mobile - QR platba*X-CUSTOM:orang utan*RN:T-Mobile Czech Republic a.s.*X-VS:1113334445*X-SS:11"
val decoder = Spayd.Decoder.Builder().logger(Logger.PRINTLN).build()
val decodedSpayd = decoder.decode(receivedSpayd)
assertEquals(constructedSpayd, decodedSpayd)
val encoder = Spayd.Encoder.Builder().includeCrc32(true).logger(Logger.PRINTLN).build()
val expectedEncoded =
"SPD*1.0*ACC:CZ5207100007210077628031*ALT-ACC:CZ5207100007210077628031,CZ4601000000192235210247*AM:599*CC:CZK*MSG:T-Mobile - QR platba*RN:T-Mobile Czech Republic a.s.*X-CUSTOM:orang utan*X-SS:11*X-VS:1113334445*CRC32:D7A7B86C*"
val actualEncoded = encoder.encode(constructedSpayd)
assertEquals(expectedEncoded, actualEncoded)
assertEquals(decodedSpayd, decoder.decode(actualEncoded))
assertEquals(constructedSpayd, decoder.decode(actualEncoded))
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