See www.servicestack.net for an overview.
Join the ServiceStack Google+ Community or follow @ServiceStack for project updates. You can catch some community members hanging out on JabbR.
Service Stack is a high-performance .NET web services platform that simplifies the development of high-performance REST (JSON, XML, JSV, HTML, MsgPack, ProtoBuf, CSV) and WCF SOAP Web Services.
Note: the source code is provided as-is - no direct or commercial support is available for ServiceStack
This example is also available as a stand-alone integration test:
//Web Service Host Configuration
public class AppHost : AppHostHttpListenerBase
{
    public AppHost() : base("TODOs Tests", typeof(Todo).Assembly) {}
    public override void Configure(Container container)
    {
        container.Register(new TodoRepository());
    }
}
//REST Resource DTO
[Route("/todos")]
[Route("/todos/{Ids}")]
public class Todos : IReturn<List<Todo>>
{
    public long[] Ids { get; set; }
    public Todos(params long[] ids)
    {
        this.Ids = ids;
    }
}
[Route("/todos", "POST")]
[Route("/todos/{Id}", "PUT")]
public class Todo : IReturn<Todo>
{
    public long Id { get; set; }
    public string Content { get; set; }
    public int Order { get; set; }
    public bool Done { get; set; }
}
public class TodosService : Service
{
    public TodoRepository Repository { get; set; }  //Injected by IOC
    public object Get(Todos request)
    {
        return request.Ids.IsEmpty()
            ? Repository.GetAll()
            : Repository.GetByIds(request.Ids);
    }
    public object Post(Todo todo)
    {
        return Repository.Store(todo);
    }
    public object Put(Todo todo)
    {
        return Repository.Store(todo);
    }
    public void Delete(Todos request)
    {
        Repository.DeleteByIds(request.Ids);
    }
}//no code-gen required, can re-use above DTO's
var restClient = new JsonServiceClient(BaseUri);
List<Todo> all = restClient.Get(new Todos());     		// Count = 0
var todo = restClient.Post(
    new Todo { Content = "New TODO", Order = 1 }); 	    // todo.Id = 1
all = restClient.Get(new Todos());						// Count = 1
todo.Content = "Updated TODO";
todo = restClient.Put(todo);							// todo.Content = Updated TODO
restClient.Delete(new Todos(todo.Id));
all = restClient.Get(new Todos());						// Count = 0$.getJSON(baseUri, function(todos) {
	alert(todos.length == 1);
});
Calling the TODO REST service from Dart JsonClient
var client = new JsonClient(baseUri);
client.todos()
	.then((todos) => alert(todos.length == 1) ); 
That's all the application code required to create a simple REST web service.
If you have NuGet installed, the easiest way to get started is to install ServiceStack via NuGet:
ServiceStack binaries only: Minimal installation of ServiceStack containing only the core-binaries (.NET 3.5+)
ServiceStack with Razor Support: Create an empty ASP.NET Web or Console Application and (.NET 4.0+)
Note: the binary packages are provided as-is - no direct or commercial support is available for ServiceStack
The Definitive list of Example Projects, Use-Cases, Demos, Starter Templates
GitHub has disabled its download feature so currently NuGet is the best way to get ServiceStack published releases. For environments that don't have NuGet installed (e.g. OSX/Linux) you can still download the published binaries by extracting them from the published NuGet packages. The url to download a nuget package is:
http://packages.nuget.org/api/v1/package/{PackageName}/{Version}
So to get the core ServiceStack and ServiceStack.Text libs in OSX/Linux (or using gnu tools for Windows) you can just do:
wget -O ServiceStack http://packages.nuget.org/api/v1/package/ServiceStack/3.9.60
unzip ServiceStack 'lib/*'
wget -O ServiceStack.Text http://packages.nuget.org/api/v1/package/ServiceStack.Text/3.9.60
unzip ServiceStack.Text 'lib/*'
which will download and extract the dlls into your local local lib/ folder.
Release notes for major releases
ServiceStack includes source code of the great libraries below for some of its core functionality. Each library is released under its respective licence:
- Mono (License)
 - Funq IOC (License)
 - Fluent Validation (License)
 - Mini Profiler (License)
 - Dapper (License)
 - TweetStation's OAuth library (License)
 - MarkdownSharp (License)
 - MarkdownDeep (License)
 
Similar Open source .NET projects for developing or accessing web services include:
- Nancy Fx - A Sinatra-inspired lightweight Web Framework for .NET:
 - Fubu MVC - A "Front Controller" pattern-style MVC framework designed for use in web applications built on ASP.NET:
 - Rest Sharp - An open source REST client for .NET
 
Follow @ServiceStack and +ServiceStack for project updates.
A big thanks to GitHub and all of ServiceStack's contributors:
- bman654 (Brandon Wallace)
 - iristyle (Ethan Brown)
 - superlogical (Jake Scott)
 - itamar82
 - chadwackerman
 - derfsplat
 - johnacarruthers (John Carruthers)
 - mvitorino (Miguel Vitorino)
 - bsiegel (Brandon Siegel)
 - mdavid (M. David Peterson)
 - lhaussknecht (Louis Haussknecht)
 - grendello (Marek Habersack)
 - SteveDunn (Steve Dunn)
 - kcherenkov (Konstantin Cherenkov)
 - timryan (Tim Ryan)
 - letssellsomebananas (Tymek Majewski)
 - danbarua (Dan Barua)
 - JonCanning (Jon Canning)
 - paegun (James Gorlick)
 - pvasek (pvasek)
 - derfsplat (derfsplat)
 - justinrolston (Justin Rolston)
 - danmiser (Dan Miser)
 - danatkinson (Dan Atkinson)
 - brainless83 (Thomas Grassauer)
 - angelcolmenares (angel colmenares)
 - dbeattie71 (Derek Beattie)
 - danielwertheim (Daniel Wertheim)
 - greghroberts (Gregh Roberts)
 - int03 (Selim Selçuk)
 - andidog (AndiDog)
 - chuckb (chuckb)
 - niemyjski (Blake Niemyjski)
 - mj1856 (Matt Johnson)
 - matthieugd (Matthieu)
 - tomaszkubacki (Tomasz Kubacki)
 - e11137 (Rogelio Canedo)
 - davidroth (David Roth)
 - meebey (Mirco Bauer)
 - codedemonuk (Pervez Choudhury)
 - jrosskopf (Joachim Rosskopf)
 - friism (Michael Friis)
 - mp3125
 - aurimas86
 - parnham (Dan Parnham)
 - yeurch (Richard Fawcett)
 - damianh (Damian Hickey)
 - freeman (Michel Rasschaert)
 - kvervo (Kvervo)
 - pauldbau (Paul Du Bois)
 - justinpihony (Justin Pihony)
 - bokmadsen (Bo Kingo Damgaard)
 - dragan (Dale Ragan)
 - sneal (Shawn Neal)
 - johnsheehan (John Sheehan)
 - jschlicht (Jared Schlicht)
 - kumarnitin (Nitin Kumar)
 - davidchristiansen (David Christiansen)
 - paulecoyote (Paul Evans)
 - kongo2002 (Gregor Uhlenheuer)
 - brannonking (Brannon King)
 - alexandrerocco (Alexandre Rocco)
 - cbarbara
 - assaframan (Assaf Raman)
 - csakshaug (Christian Sakshaug)
 - johnman
 - jarroda
 - ssboisen (Simon Skov Boisen)
 - paulduran (Paul Duran)
 - pruiz (Pablo Ruiz García)
 - fantasticjamieburns
 - pseabury
 - kevingessner (Kevin Gessner)
 - iskomorokh (Igor Skomorokh)
 - royjacobs (Roy Jacobs)
 - robertmircea (Robert Mircea)
 - markswiatek (Mark Swiatek)
 - flq (Frank Quednau)
 - ashd (Ash D)
 - thanhhh
 - algra (Alexey Gravanov)
 - jimschubert (Jim Schubert)
 - gkathire
 - mikaelwaltersson (Mikael Waltersson)
 - asunar (Alper)
 - chucksavage (Chuck Savage)
 - sashagit (Sasha)
 - froyke (Froyke)
 - dbhobbs (Daniel Hobbs)
 - bculberson (Brad Culberson)
 - awr (Andrew)
 - pingvinen (Patrick)
 - citndev (Sebastien Curutchet)
 - cyberprune
 - jorbor (Jordan Hayashi)
 - bojanv55
 - i-e-b (Iain Ballard)
 - pietervp (Pieter Van Parys)
 - franklinwise
 - ckasabula (Chuck Kasabula)
 - dortzur (Dor Tzur)
 - allenarthurgay (Allen Gay)
 - viceberg
 - vansha (Ivan Korneliuk)
 - aaronlerch (Aaron Lerch)
 - glikoz
 - danielcrenna (Daniel Crenna)
 - stevegraygh (Steve Graygh)
 - jrmitch120 (Jeff Mitchell)
 - manuelnelson (Manuel Nelson)
 - babcca (Petr Babicka)
 - jgeurts (Jim Geurts)
 - driis (Dennis Riis)
 - gshackles (Greg Shackles)
 - jsonmez (John Sonmez)
 - dchurchland (David Churchland)
 - softwx (Steve Hatchett)
 - ggeurts (Gerke Geurts)
 - andrewrissing (Andrew Rissing)
 - jjavery (James Javery)
 - suremaker (Wojtek)
 - cheesebaron (Tomasz Cielecki)
 - mikkelfish (Mikkel Fishman)
 - johngibb (John Gibb)
 - stabbylambda (David Stone)
 - mikepugh (Mike Pugh)
 - permalmberg (Per Malmberg)
 - adamralph (Adam Ralph)
 - shamsulamry (Shamsul Amry)
 - peterlazzarino (Peter Lazzarino)
 - kevin-montrose (Kevin Montrose)
 - msarchet (Michael Sarchet)
 - jeffgabhart (Jeff Gabhart)
 - pkudinov (Pavel Kudinov)
 - permalmberg (Per Malmberg)
 - namman (Nick Miller)
 - leon-andria (Leon Andria)
 - kkolstad (Kenneth Kolstad)
 - electricshaman (Jeff Smith)
 - ecgan (Gan Eng Chin)
 - its-tyson (Tyson Stolarski)
 - tischlda (David Tischler)
 - connectassist (Carl Healy)
 - starteleport
 - jfoshee (Jacob Foshee)
 - nardin (Mamaev Michail)
 - cliffstill
 - somya (Somya Jain)
 - thinkbeforecoding (Jérémie Chassaing)
 - paksys (Khalil Ahmad)
 - mcguinness (Karl McGuinness)
 - jpasichnyk (Jesse Pasichnyk)
 - waynebrantley (Wayne Brantley)
 - dcartoon (Dan Cartoon)
 - alexvodovoz (Alex Vodovoz)
 - jluchiji (Denis Luchkin-Zhou)
 - grexican
 - akoslukacs (Ákos Lukács)
 - medianick (Nick Jones)
 - arhoads76
 - dylanvdmerwe (Dylan v.d Merwe)
 - mattiasw2 (Mattias)
 - paultyng (Paul Tyng)
 - h2oman (Jason Waterman)
 - anewton (Allen Newton)
 - sami1971
 - russellchadwick (Russell Chadwick)
 - cyberzed (Stefan Daugaard Poulsen)
 - filipw (Filip Wojcieszyn)
 - ghuntley (Geoffrey Huntley)
 - baramuse
 - pdegenhardt (Phil Degenhardt)
 - captncraig (Craig Peterson)
 - abattery (Jae sung Chung)
 - biliktamas79
 - garuma (Jérémie Laval)
 - dsimunic
 - adamfowleruk (Adam Fowler)
 - bfriesen (Brian Friesen)
 - roryf (Rory Fitzpatrick)
 - stefandevo
 - gdassac
 - metal10k
 - cmelgarejo
 - skaman
 - rossipedia (Bryan J. Ross)
 - wimatihomer (Wim Pool)
 - sword-breaker
 - adebisi-fa (Adebisi Foluso A.)
 - mbischoff (M. Bischoff)
 - ivanfioravanti (Ivan Fioravanti)
 - inhibition (Keith Hassen)
 - joshearl (Josh Earl)
 - friism (Michael Friis)
 - corkupine
 - bchavez (Brian Chavez)
 - nhhagen (Niels Henrik Hagen)
 - daggmano (Darren Oster)
 - chappoo (Steve Chapman)
 - julrichkieffer (Julrich Kieffer)
 - adamclarsen (Adam Larsen)
 - joero74 (Joerg Rosenkranz)
 - ddotlic (Drazen Dotlic)
 - chrismcv (Chris McVittie)
 - marcioalthmann (Márcio Fábio Althmann)
 - mmertsock (Mike Mertsock)
 - johnkamau (John Kamau)
 - uhaciogullari (Ufuk Hacıoğulları)
 - davybrion (Davy Brion)
 - aleshi (Alexander Shiryaev)
 - alexandryz (Alexandr Zaozerskiy)
 - mistobaan (Fabrizio Milo)
 - niemyjski (Blake Niemyjski)
 - alexandernyquist (Alexander Nyquist)
 - mcduck76
 - kojoru
 - jeremy-bridges (Jeremy Bridges)
 - andreabalducci (Andrea Balducci)
 - robertthegrey (Robert Greyling)
 - robertbeal (Robert Beal)
 - improvedk (Mark Rasmussen)
 - foresterh (Jamie Houston)
 - peterkahl (Peter Kahl)
 - helgel
 - anthonycarl (Anthony Carl)
 - mrjul (Julien Lebosquain)
 - pwhe23 (Paul Wheeler)
 - aleksd
 - miketrebilcock (Mike Trebilcock)
 - markwoodhall (Mark Woodhall)
 - theonlylawislove (Paul Knopf)
 - callumvass (Callum Vass)
 - bpruitt-goddard
 - gregpakes (Greg Pakes)
 - caspiancanuck (Caspian Canuck)
 - merwer
 - pavelsavara (Pavel Savara)
 - markwalls (Mark Walls)
 - prasannavl (Prasanna Loganathar)
 - wilfrem
 - emiba
 - lucky-ly (Dmitry Svechnikov)
 - hhandoko (Herdy Handoko)
 - datawingsoftware
 - tal952
 - bretternst
 - kevinhoward (Kevin Howard)
 - mattbutton (Matt Button)
 - torbenrahbekkoch (Torben Rahbek Koch)
 - pilotmartin (Pilot Martin)
 - catlion
 - tstade (Toft Stade)
 - niltz (Jeff Sawatzky)
 - nhalm
 - fhurta (Filip Hurta)
 - discobanan
 - x-cray
 - jeremistadler (Jeremi Stadler)
 - bangbite
 - felipesabino (Felipe Sabino)
 - xelom (Arıl Bozoluk)
 - shiweichuan (Weichuan Shi)
 - kojoru (Konstantin Yakushev)
 - eddiegroves (Eddie Groves)
 - fetters5
 - rcollette (Richard Collette)
 - urihendler (Uri Hendler)
 - laurencee (Laurence Evans)
 - m-andrew-albright (Andrew Albright)
 - lee337 (Lee Venkatsamy)
 - kaza
 - mishfit
 - rfvgyhn (Chris)
 - caioproiete (Caio Proiete)
 - sjuxax (Jeff Cook)
 - madaleno (Luis Madaleno)
 - yavosh (Yavor Shahpasov)
 - fvoncina (Facundo Voncina)
 - devrios (Dev Rios)
 - bfkelsey (Ben Kelsey)
 - maksimenko
 - dixon (Jarrod Dixon)
 - kal (Kal Ahmed)
 
Runs on both Mono and .NET (Live preview hosted on Mono / Ubuntu)

