SOAP cheat sheet

A scannable SOAP reference: 10 short snippets across 7 topics, each linking back to the lesson it came from.

At a glance

Topic	What it covers
WSDL contracts and code generation	Generated code turns the contract into classes and a proxy whose methods look like local calls. The WSDL becomes your	lesson
Calling a SOAP service, and why REST usually wins	REST wins for new work because it leans on what HTTP already gives you — methods, status codes, caching, proxies — and	lesson
SOAP 1.1 versus 1.2 and HTTP bindings	The two versions differ in namespace, content type and how faults travel over HTTP, and a client that guesses wrong	lesson
Building a SOAP service: contract-first and code-first	The direction you choose is really a decision about where the review of the interface happens. Contract-first puts it	lesson
Attachments and binary data: MTOM and SwA	Base64 inside the envelope is simple and wasteful. MTOM keeps the XML readable and sends the bytes as raw binary	lesson
Interoperability between .NET, Java and legacy stacks	Most cross-vendor failures come from a handful of known divergences in encoding, dates, nulls and empty collections	lesson
SOAP in the enterprise: ESBs, gateways and middleware	In large organisations SOAP rarely reaches the service directly. Knowing what the gateway does explains most	lesson

Quick snippets

WSDL contracts and code generation

Generating a client

# Java: JDK ships wsimport; Jakarta's wsdl2java is the maintained option
wsimport -keep -p com.example.quotes -d out https://api.example.com/quotes?wsdl
wsdl2java -d out -p com.example.quotes https://api.example.com/quotes?wsdl

# .NET
dotnet svcutil https://api.example.com/quotes?wsdl

# Python: ask for a plain dictionary instead of a proxy class
python -m zeep https://api.example.com/quotes?wsdl

Full lesson: WSDL contracts and code generation →

Calling a SOAP service, and why REST usually wins

The call on the wire

curl -sS https://api.example.com/quotes \
  -H 'Content-Type: text/xml; charset=utf-8' \
  -H 'SOAPAction: "urn:example:quotes/GetQuote"' \
  --data-binary @request.xml

Full lesson: Calling a SOAP service, and why REST usually wins →

SOAP 1.1 versus 1.2 and HTTP bindings

What actually differs

POST /OrderService HTTP/1.1
Content-Type: text/xml; charset=utf-8
SOAPAction: "urn:example:orders/PlaceOrder"

<?xml version="1.0"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <PlaceOrder xmlns="urn:example:orders"><sku>A-1</sku><qty>2</qty></PlaceOrder>
  </soap:Body>
</soap:Envelope>

What actually differs

POST /OrderService HTTP/1.1
Content-Type: application/soap+xml; charset=utf-8; action="urn:example:orders/PlaceOrder"

<?xml version="1.0"?>
<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">
  <env:Body>
    <PlaceOrder xmlns="urn:example:orders"><sku>A-1</sku><qty>2</qty></PlaceOrder>
  </env:Body>
</env:Envelope>

Full lesson: SOAP 1.1 versus 1.2 and HTTP bindings →

Building a SOAP service: contract-first and code-first

The mechanics of each direction

# Contract-first with JAX-WS: generate the portable artifacts, then implement
wsimport -keep -p com.example.orders -d build/classes contract.wsdl

# .NET: generate a client or a server-side abstract class
dotnet tool install --global dotnet-svcutil
dotnet-svcutil contract.wsdl --outputDir Generated

# Java: publish a contract-first endpoint without a container
# (endpoint is the portable JAX-WS API)
#   Endpoint.publish("http://0.0.0.0:8080/orders", new OrderServiceImpl());
# then check it
curl -s "http://localhost:8080/orders?wsdl" | head -20

Full lesson: Building a SOAP service: contract-first and code-first →

Attachments and binary data: MTOM and SwA

Three ways to send bytes

Content-Type: multipart/related; type="application/xop+xml";
              start="<[email protected]>"; start-info="application/soap+xml";
              boundary="MIME_boundary"

Practical rules

// Enable MTOM on a WCF-style binding and stream the body
var binding = new BasicHttpBinding
{
    MessageEncoding = WSMessageEncoding.Mtom,
    TransferMode = TransferMode.Streamed,
    MaxReceivedMessageSize = 64L * 1024 * 1024,
    ReaderQuotas = { MaxArrayLength = 64 * 1024 * 1024 }
};
// TransferMode.Streamed matters more than the size limits:
// it keeps the payload off the managed heap.

Full lesson: Attachments and binary data: MTOM and SwA →

Interoperability between .NET, Java and legacy stacks

The known divergences

# Normalise both responses and diff them
xsltproc tools/compare.xsl java-response.xml > java.txt
xsltproc tools/compare.xsl dotnet-response.xml > dotnet.txt
diff -u java.txt dotnet.txt

Full lesson: Interoperability between .NET, Java and legacy stacks →

SOAP in the enterprise: ESBs, gateways and middleware

What the middleware does

<!-- A gateway-added header you should expect and tolerate -->
<soap:Header>
  <gw:RoutingId xmlns:gw="urn:example:gateway">abc-123</gw:RoutingId>
  <gw:ReceivedAt xmlns:gw="urn:example:gateway">2026-09-18T10:00:03Z</gw:ReceivedAt>
  <wsse:Security><!-- the gateway may replace the original token --></wsse:Security>
</soap:Header>

What the middleware does

# Prove where a failure happens: measure the gap between hops
curl -s -o /dev/null -w 'gateway connect=%{time_connect} total=%{time_total}\n' \
  -X POST https://gateway.example.com/orders --data-binary @req.xml

curl -s -o /dev/null -w 'direct   connect=%{time_connect} total=%{time_total}\n' \
  -X POST https://orders.internal/OrderService --data-binary @req.xml

Full lesson: SOAP in the enterprise: ESBs, gateways and middleware →

FAQ

Is this SOAP cheat sheet free to use?

Yes. No sign-up and no tracking: the page is static, every example is on the page itself, and you can print it or save it as a one-page reference.

Where do the examples come from?

Every snippet is taken from the 7 lessons of the SOAP course on this site, and each section links back to the lesson it was pulled from.

How do I go deeper than a cheat sheet?

Open the full SOAP course — it carries the worked explanations, the edge cases and the exercises behind every line here.

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Last refreshed 2026-09-27.