spring-ai/providers/README.md

providers

Companion code for Anthropic Claude vs OpenAI vs Gemini in Spring AI 2.0: Switching Providers and Comparing Cost, part of the Spring AI series on ankurm.com.

One small application (TicketService, which summarises a support ticket) runs on the real OpenAiChatModel, AnthropicChatModel and GoogleGenAiChatModel, and the tests look at what each one does differently.

No vendor API was called, and no claim is made about any vendor's behaviour. FakeProviderServer is a local HTTP server that answers in the three wire formats. It records every request the real Spring AI classes send, which is the evidence for the "what is different on the wire" results. Three things in it are simulation: token counts are characters / 4, the answer is a fixed JSON string, and cache hits follow the rules the vendors document (thresholds and prefix matching, read on 2026-10-09) applied to the request that really arrived. So the cost table is a worked example of the price sheets, not a bill, and latency is not measured at all.

Versions

Component	Version
Spring Boot	4.1.1 (parent)
Spring AI	2.0.1 (spring-ai-openai, spring-ai-anthropic, spring-ai-google-genai)
Models named in the examples	gpt-6.1-sol, claude-sonnet-5-5, gemini-3.8-flash
Java	25 (LTS)

Quickstart

scripts/run-all.sh     # runs the suite, regenerates output/01 .. 05

Two consecutive runs produce byte-identical files.

What's here

File	What it is
ProviderModels.java	The one class that knows which vendor is behind a ChatModel
TicketService.java	The application; sees only ChatModel
FallbackChatModel.java	Tries providers in order on transient failures
Failures.java	Reads an HTTP status out of three unrelated exception families
Cost.java	Usage to dollars, with the per-provider meaning of "prompt tokens"

Output files

File	Written by
01-wire.txt	WireTest: the same call as each provider's HTTP request
02-options.txt	OptionsTest: portable and provider-specific options, and the per-call trap
03-caching.txt	CachingTest: breakpoints sent, cache tokens reported, text order
04-cost.txt	CostTest: 100 requests priced on three price sheets
05-fallback.txt	FallbackTest: which failures fail over, and requests per plan