feat(providers): add EURouter as an OpenAI-compatible gateway (#12985) (#13025)

Rebased onto the release tip after #13024 landed: both PRs extend the same three registration files, so the sibling merge turned this into a conflict. The resolution is additive — both catalog entries kept, both registry imports kept, both base URLs kept — and EURouter stays in AGGREGATOR_PROVIDER_IDS while GreenPT stays out, exactly as each PR argued. 14 provider tests pass on the rebased branch and the file-size gate is green under the annotated rebaseline.

Thank you for re-checking the endpoint live instead of trusting the report, and for the sovereignty caveat. Naming the upstreams from EURouter's own catalog — Claude Sonnet served by AWS Bedrock, 19 models owned by openai — and then writing an apiHint that says routing rather than residency is the kind of care that keeps a provider entry honest. The test asserting the copy contains none of "residency", "stays in the EU", "EU-hosted" or "sovereign" is a good guard against that drifting later.

changelog.d/features/12985-eurouter-provider.md

@@ -0,0 +1 @@
+- **feat(providers):** Added EURouter as an OpenAI-compatible API-key gateway (`https://api.eurouter.ai/v1`), with live model discovery via `passthroughModels`. Its copy states that models are served by third-party upstreams listed per model, so an EU-based router is not read as EU data residency for inference.

open-sse/config/providers/index.ts

@@ -250,6 +250,7 @@ import { llmgatewayProvider } from "./registry/llmgateway/index.ts";
 import { llmKiwiProvider } from "./registry/llm-kiwi/index.ts";
 import { literouterProvider } from "./registry/literouter/index.ts";
 import { greenptProvider } from "./registry/greenpt/index.ts";
+import { eurouterProvider } from "./registry/eurouter/index.ts";
 import { mnnAiProvider } from "./registry/mnn-ai/index.ts";
 import { meganovaAiProvider } from "./registry/meganova-ai/index.ts";
 import { mixlayerProvider } from "./registry/mixlayer/index.ts";
@@ -526,6 +527,7 @@ export const REGISTRY: Record<string, RegistryEntry> = {
   "llm-kiwi": llmKiwiProvider,
   literouter: literouterProvider,
   greenpt: greenptProvider,
+  eurouter: eurouterProvider,
   "mnn-ai": mnnAiProvider,
   "meganova-ai": meganovaAiProvider,
   mixlayer: mixlayerProvider,

open-sse/config/providers/registry/eurouter/index.ts

@@ -0,0 +1,11 @@
+import type { RegistryEntry } from "../../shared.ts";
+import { buildOpenAiCompatibleRegistryEntry } from "../../shared.ts";
+
+export const eurouterProvider: RegistryEntry = buildOpenAiCompatibleRegistryEntry({
+  id: "eurouter",
+  alias: "eurouter",
+  baseUrl: "https://api.eurouter.ai/v1/chat/completions",
+  modelsUrl: "https://api.eurouter.ai/v1/models",
+  models: [],
+  passthroughModels: true,
+});

src/shared/constants/config.ts

@@ -18,6 +18,7 @@ export const PROVIDER_ENDPOINTS = {
   "llm-kiwi": "https://api.llm.kiwi/v1/chat/completions",
   literouter: "https://api.literouter.com/v1/chat/completions",
   greenpt: "https://api.greenpt.ai/v1/chat/completions",
+  eurouter: "https://api.eurouter.ai/v1/chat/completions",
   "mnn-ai": "https://api.mnnai.ru/v1/chat/completions",
   "meganova-ai": "https://api.meganova.ai/v1/chat/completions",
   mixlayer: "https://models.mixlayer.ai/v1/chat/completions",

src/shared/constants/providers.ts

@@ -123,6 +123,7 @@ export const AGGREGATOR_PROVIDER_IDS = new Set([
   "llmgateway",
   "llm-kiwi",
   "literouter",
+  "eurouter",
   "mnn-ai",
   "meganova-ai",
   "mixlayer",

src/shared/constants/providers/apikey/gateways.ts

@@ -285,6 +285,27 @@ export const APIKEY_PROVIDERS_GATEWAYS = {
     apiHint:
       "Create a GreenPT API key, then use https://api.greenpt.ai/v1 as the OpenAI-compatible base URL. Review jurisdiction, privacy and regional data-transfer requirements before use.",
   },
+  eurouter: {
+    id: "eurouter",
+    serviceKinds: ["llm"],
+    alias: "eurouter",
+    name: "EURouter",
+    icon: "router",
+    color: "#1D4ED8",
+    textIcon: "EUR",
+    passthroughModels: true,
+    website: "https://eurouter.ai",
+    // No free allowance is published, so no badge. A key was accepted but the
+    // account had no credits, so nothing about pricing tiers is claimed here.
+    hasFree: false,
+    // Deliberately says routing, not residency. EURouter is a router: its own
+    // catalog names the upstream that serves each model (claude-sonnet-5 ->
+    // AWS Bedrock, and 19 models owned by openai, 9 by anthropic, 7 by amazon).
+    // An EU-based router is a routing layer in the EU; where a model actually
+    // executes, and under whose terms, is a per-upstream property (#12985).
+    apiHint:
+      "Create an EURouter API key, then use https://api.eurouter.ai/v1 as the OpenAI-compatible base URL. Models are served by third-party upstreams listed per model in the EURouter catalog; check each upstream jurisdiction, privacy and data-transfer terms before use.",
+  },
   "mnn-ai": {
     id: "mnn-ai",
     serviceKinds: ["llm"],

tests/unit/eurouter-provider.test.ts

@@ -0,0 +1,85 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { eurouterProvider } from "../../open-sse/config/providers/registry/eurouter/index.ts";
+
+const { REGISTRY } = await import("../../open-sse/config/providerRegistry.ts");
+const { DefaultExecutor, getExecutor } = await import("../../open-sse/executors/index.ts");
+const { PROVIDER_ENDPOINTS } = await import("../../src/shared/constants/config.ts");
+const { isValidModel } = await import("../../src/shared/constants/models.ts");
+const { APIKEY_PROVIDERS } = await import("../../src/shared/constants/providers/apikey/index.ts");
+const { AGGREGATOR_PROVIDER_IDS } = await import("../../src/shared/constants/providers.ts");
+
+const CHAT_URL = "https://api.eurouter.ai/v1/chat/completions";
+const MODELS_URL = "https://api.eurouter.ai/v1/models";
+
+test("eurouter is an OpenAI-compatible Bearer registry entry", () => {
+  assert.equal(eurouterProvider.id, "eurouter");
+  assert.equal(eurouterProvider.alias, "eurouter");
+  assert.equal(eurouterProvider.format, "openai");
+  assert.equal(eurouterProvider.executor, "default");
+  assert.equal(eurouterProvider.authType, "apikey");
+  assert.equal(eurouterProvider.authHeader, "bearer");
+  assert.equal(eurouterProvider.baseUrl, CHAT_URL);
+  assert.equal(eurouterProvider.modelsUrl, MODELS_URL);
+  assert.equal(eurouterProvider.passthroughModels, true);
+});
+
+test("eurouter leaves its 147-model catalog to live discovery", () => {
+  assert.deepEqual(eurouterProvider.models, []);
+});
+
+test("eurouter is wired through registry, metadata, endpoint and default executor", async () => {
+  assert.equal(REGISTRY.eurouter?.baseUrl, CHAT_URL);
+  assert.equal(PROVIDER_ENDPOINTS.eurouter, CHAT_URL);
+  assert.equal(APIKEY_PROVIDERS.eurouter?.id, "eurouter");
+  assert.equal(APIKEY_PROVIDERS.eurouter?.alias, "eurouter");
+  assert.ok((await getExecutor("eurouter")) instanceof DefaultExecutor);
+  assert.equal(isValidModel("eurouter", "future/live-catalog-model"), true);
+});
+
+test("eurouter is listed as an aggregator", () => {
+  // It routes to third-party upstreams rather than serving its own inference,
+  // which is what that set means -- the opposite call from GreenPT (#12986).
+  assert.equal(AGGREGATOR_PROVIDER_IDS.has("eurouter"), true);
+});
+
+test("eurouter advertises no free allowance", () => {
+  // A key was accepted (HTTP 402 Insufficient balance) but the account had no
+  // credits, so no pricing tier was observed and none is claimed.
+  assert.equal(APIKEY_PROVIDERS.eurouter?.hasFree, false);
+  assert.equal(APIKEY_PROVIDERS.eurouter?.freeNote, undefined);
+});
+
+test("eurouter copy does not imply EU residency for inference", () => {
+  // The name invites that reading and the catalog contradicts it: models are
+  // served by upstreams such as AWS Bedrock. Being EU-based is a property of
+  // the routing layer, not of where a model executes (#12985).
+  const hint = String(APIKEY_PROVIDERS.eurouter?.apiHint ?? "");
+  assert.ok(hint.length > 0, "an apiHint is required to carry the caveat");
+  for (const claim of [
+    "data residency",
+    "residency",
+    "stays in the EU",
+    "EU-hosted",
+    "sovereign",
+  ]) {
+    assert.ok(
+      !hint.toLowerCase().includes(claim.toLowerCase()),
+      `apiHint must not claim "${claim}"`
+    );
+  }
+  assert.ok(
+    hint.toLowerCase().includes("third-party upstream"),
+    "apiHint must say the models are served by third-party upstreams"
+  );
+});
+
+test("eurouter claims no capability that was not exercised", () => {
+  // Streaming SSE conformance was not exercised -- the usual place these
+  // gateways diverge, and a passthrough entry breaks there silently.
+  const metadata = APIKEY_PROVIDERS.eurouter as Record<string, unknown>;
+  for (const key of ["supportsTools", "supportsVision", "capabilities"]) {
+    assert.equal(metadata[key], undefined, `${key} must not be declared unverified`);
+  }
+});