Tomasz Kowalski
Java, C# and Go back ends for sthan.io
Tomasz writes the server-side track for C#, Java and Go: verification, parsing and autocomplete from ASP.NET Core, Spring Boot and Go's net/http, plus full integration guides for C# and Java.
The articles use each language's standard tools (typed HttpClient services, Jackson records, typed structs) and the verification articles end with the code that decides what to do with each answer: accept, warn or block.
- 10 articles
- 114 minutes of reading
- .NET 6+, Java 11+, Go 1.18+
- Latest: Jun 27, 2026
What Tomasz covers
Pick the job and the framework. Every filled cell is one article.
| Job | C# / ASP.NET Core | Java / Spring Boot | Go |
|---|---|---|---|
| Check an address is deliverable | Verify in C# typed HttpClient service, branches on DPV | Verify in Java built-in HttpClient with Jackson records | Verify in Go net/http client, http.HandlerFunc |
| Split an address into fields | Parse in C# one field per component | Parse in Java HttpClient with Jackson records | Parse in Go typed structs |
| Suggest addresses as people type | Autocomplete in C# proxy controller and a debounced input | Autocomplete in Java RestClient service and a controller proxy | No article yet |
| All the APIs in one guide | Integrate address APIs in C# dependency injection, async patterns | Integrate address APIs in Java Spring Boot, error handling | No article yet |
Where to start
A reading order for a back-end developer.
-
The integration guide for your language 15 minC# or Java: start with the full guide for setup, error handling and rate limits. In Go, start with Verify in Go.
-
Verify on submit 10 to 11 minReject or flag bad addresses before they reach your database.
-
Parse for storage 10 to 11 minSplit addresses into one field per component.
-
Autocomplete for the form 10 minC# and Java: serve suggestions through your own controller.
Questions these articles answer
Each question links to the answer inside the article.
Getting started
- How do I verify a US address in C# / ASP.NET Core? Verify in C#
- How do I verify a US address in Java? Verify in Java
- How do I verify a US address in Go? Verify in Go
- Can I use sthan.io address APIs with Spring Boot? Java integration guide
- Can I use these APIs in a Blazor application? C# integration guide
Clients and JSON
- Should I use HttpClient directly or IHttpClientFactory in C#? C# integration guide
- Which HTTP client should I use for calling address APIs in Java? Java integration guide
- How do I deserialize the sthan.io API response in C#? C# integration guide
- How do I parse the JSON response from the address API in Java? Java integration guide
- Is the sthan.io Java integration thread-safe? Java integration guide
Production
- How do I handle rate limiting with sthan.io APIs in C#? C# integration guide
- How do I handle rate limiting when calling address APIs from Java? Java integration guide
- How should I store API credentials securely in a .NET application? C# integration guide
- How do I process addresses in bulk with Java? Java integration guide
Reading the answer
- What is the difference between Confirmed, ConfirmedPrimaryOnly, NotDeliverable, and Unknown? Verify in C#
- Which match mode should I use for address verification? Verify in C#
- Does the API return the apartment or unit number separately? Verify in C#
- What components does the address parser return? Parse in C#
What the code assumes
- C#
- .NET 6 or newer (examples also cover .NET 8)
- Java
- Java 11+ for verify and parse; Java 17+ and Spring Boot 3.2+ for autocomplete
- Go
- Go 1.18 or newer, standard library net/http
- HTTP clients
- HttpClient and IHttpClientFactory, Java's built-in HttpClient and RestClient, net/http
Related on sthan.io
All articles by Tomasz
How to Add Address Autocomplete in C# / ASP.NET Core
Add US address autocomplete to your ASP.NET Core app. Free API, a typed HttpClient service, a backend proxy controller, and a debounced front-end input.
How to Add Address Autocomplete in Java / Spring Boot
Add US address autocomplete to your Spring Boot app. Free API, a RestClient service, a controller proxy, and a debounced front-end input.
How to Verify US Addresses in C# / ASP.NET Core
Confirm deliverability at submit. Free API, a typed HttpClient service, and an endpoint that branches on DPV - accept, warn, or block.
How to Verify US Addresses in Java / Spring Boot
Confirm deliverability at submit. Free API, the built-in HttpClient with Jackson records, and a controller that branches on DPV.
How to Verify US Addresses in Go
Confirm deliverability at submit. Free API, a net/http client with typed structs, and an http.HandlerFunc that branches on DPV.
How to Parse US Addresses in C# / ASP.NET Core
Split freeform addresses into structured components. Free API, a typed HttpClient service, one field per component.
How to Parse US Addresses in Java / Spring Boot
Split freeform addresses into structured components. Free API, the built-in HttpClient with Jackson records.
How to Parse US Addresses in Go
Split freeform addresses into structured components. Free API, a net/http client with typed structs, one field per component.
How to Integrate Address APIs in Java: Verification, Autocomplete & Geocoding
Complete Java guide with HttpClient, Spring Boot integration, error handling, and production best practices for address APIs.
How to Integrate Address APIs in C#: Verification, Autocomplete & Geocoding
Complete C# and .NET guide with HttpClient, dependency injection, async patterns, and ASP.NET Core integration for address APIs.