Per-Request Credentials

Status: Stable | Availability: SDK only

Overview

NeuroLink allows provider credentials to be supplied at two levels below the environment-variable default: on the NeuroLink constructor (instance level) and on individual generate() / stream() calls (per-call level). Credentials are resolved in the following order of precedence:

per-call credentials  >  instance credentials  >  environment variables

This enables multi-tenant architectures where different users or tenants supply their own provider API keys (bring-your-own-key, BYOK), without requiring separate NeuroLink instances per user or touching the process environment.

Typical use cases:

• Multi-tenant SaaS — each API request carries the calling user's provider key; no shared key leakage between tenants
• BYOK products — end users paste their OpenAI / Anthropic keys in settings; you forward them to NeuroLink per call
• Testing and CI — inject credentials programmatically without setting environment variables
• Provider switching — override only the active provider's credentials while leaving others to fall through to env vars

Quick Start

import { NeuroLink } from "@juspay/neurolink";

// Instance-level default: all calls from this instance use these credentials
const neurolink = new NeuroLink({
  credentials: {
    openai: { apiKey: "sk-instance-key" },
  },
});

// Per-call override: this single call uses a different key
const result = await neurolink.generate({
  input: { text: "Summarize this document" },
  provider: "openai",
  credentials: {
    openai: { apiKey: "sk-tenant-key" },
  },
});

Instance-Level vs Per-Call

Instance-Level Credentials

Set credentials in the NeuroLink constructor. These apply as the default for every generate() and stream() call made on that instance. Useful when serving a single tenant or when you have a known key for the duration of the instance lifecycle.

const neurolink = new NeuroLink({
  credentials: {
    anthropic: { apiKey: "sk-ant-..." },
    openai: { apiKey: "sk-..." },
  },
});

Per-Call Credentials

Set credentials directly on generate() or stream(). These override the instance-level credentials for that single call only. Only the providers you explicitly set are overridden — others continue falling through to instance credentials and then environment variables.

const result = await neurolink.generate({
  input: { text: "Hello" },
  provider: "anthropic",
  credentials: {
    anthropic: { apiKey: "sk-ant-user-specific-key" },
    // openai left unset — falls through to instance or env var
  },
});

Precedence Rules

Level	Scope	Set on
Per-call	Single request only	generate({ credentials }) or stream({ credentials })
Instance	All calls on instance	new NeuroLink({ credentials })
Environment	Process-wide fallback	OPENAI_API_KEY, ANTHROPIC_API_KEY, …

Unset providers at any level fall through to the next. You never need to repeat a credential at the per-call level if the instance default is correct.

Provider Credential Reference

All fields are optional — omit any field you want to fall through to a lower-precedence level.

Provider	Key	Fields
OpenAI	openai	apiKey, baseURL
Anthropic	anthropic	apiKey, oauthToken
Google AI Studio	googleAiStudio	apiKey
Google Vertex AI	vertex	projectId, location, apiKey (Express Mode), serviceAccountKey, clientEmail, privateKey
Amazon Bedrock	bedrock	accessKeyId, secretAccessKey, sessionToken, region
Amazon SageMaker	sagemaker	accessKeyId, secretAccessKey, sessionToken, region, endpoint
Azure OpenAI	azure	apiKey, resourceName, deploymentName, apiVersion
Mistral	mistral	apiKey
Hugging Face	huggingFace	apiKey, baseURL
OpenRouter	openrouter	apiKey, baseURL
LiteLLM	litellm	apiKey, baseURL
OpenAI-Compatible	openaiCompatible	apiKey, baseURL
Ollama	ollama	baseURL

The full type definition is NeurolinkCredentials in src/lib/types/providers.ts.

SDK Examples

OpenAI

const neurolink = new NeuroLink();

const result = await neurolink.generate({
  input: { text: "Explain quantum entanglement" },
  provider: "openai",
  model: "gpt-4o",
  credentials: {
    openai: { apiKey: "sk-tenant-abc123" },
  },
});

Custom base URL for OpenAI-compatible proxies:

credentials: {
  openai: { apiKey: "sk-...", baseURL: "https://my-proxy.example.com/v1" },
}

Anthropic

const result = await neurolink.generate({
  input: { text: "Write a haiku" },
  provider: "anthropic",
  credentials: {
    anthropic: { apiKey: "sk-ant-api03-..." },
  },
});

OAuth token (Anthropic Claude subscription):

credentials: {
  anthropic: { oauthToken: "eyJ..." },
}

Vertex AI — Express Mode

Express Mode uses a simple API key instead of service-account credentials, making it suitable for per-request BYOK flows:

const result = await neurolink.generate({
  input: { text: "Summarize this" },
  provider: "vertex",
  model: "gemini-2.5-pro",
  credentials: {
    vertex: {
      apiKey: "AIza...", // Express Mode key
      projectId: "my-project",
      location: "us-central1",
    },
  },
});

Full service-account credentials (server-side only — keep private keys out of client code):

credentials: {
  vertex: {
    projectId: "my-project",
    location: "us-central1",
    serviceAccountKey: JSON.stringify(serviceAccountJson),
    // OR inline fields:
    // clientEmail: "[email protected]",
    // privateKey: "-----BEGIN RSA PRIVATE KEY-----\n...",
  },
}

Amazon Bedrock

const result = await neurolink.generate({
  input: { text: "Draft a press release" },
  provider: "bedrock",
  model: "anthropic.claude-3-5-sonnet-20241022-v2:0",
  credentials: {
    bedrock: {
      accessKeyId: "AKIA...",
      secretAccessKey: "wJalrXUt...",
      region: "us-east-1",
      // sessionToken: "AQoDYXdz..." // for temporary STS credentials
    },
  },
});

Azure OpenAI

const result = await neurolink.generate({
  input: { text: "Translate to French" },
  provider: "azure",
  credentials: {
    azure: {
      apiKey: "az-key-...",
      resourceName: "my-azure-resource",
      deploymentName: "gpt-4o",
      apiVersion: "2024-02-01",
    },
  },
});

Streaming with Credentials

credentials works identically on stream(). Note that neurolink.stream() returns a StreamResult wrapper — iterate over its .stream property:

const result = await neurolink.stream({
  input: { text: "Tell me a story" },
  provider: "openai",
  credentials: {
    openai: { apiKey: "sk-tenant-xyz" },
  },
});

for await (const chunk of result.stream) {
  if ("content" in chunk && chunk.content) {
    process.stdout.write(chunk.content);
  }
}

Multi-Tenant Request Handler

A typical pattern for a multi-tenant API endpoint. Note the provider-name → credential-key mapping: the registered provider names (google-ai, openai-compatible, huggingface) differ from their NeurolinkCredentials slot keys (googleAiStudio, openaiCompatible, huggingFace), so map explicitly to avoid runtime surprises.

import { NeuroLink, type NeurolinkCredentials } from "@juspay/neurolink";

// Maps registered provider names to their NeurolinkCredentials slot keys.
// Most providers are 1:1; only the three camelCase ones need translation.
const PROVIDER_TO_CRED_KEY = {
  openai: "openai",
  anthropic: "anthropic",
  "google-ai": "googleAiStudio",
  vertex: "vertex",
  bedrock: "bedrock",
  sagemaker: "sagemaker",
  azure: "azure",
  mistral: "mistral",
  huggingface: "huggingFace",
  openrouter: "openrouter",
  litellm: "litellm",
  "openai-compatible": "openaiCompatible",
  ollama: "ollama",
} as const satisfies Record<string, keyof NeurolinkCredentials>;

// Single shared instance — no keys baked in
const neurolink = new NeuroLink();

async function handleAIRequest(req: Request) {
  const { prompt, provider, tenantApiKey } = await req.json();
  const credKey =
    PROVIDER_TO_CRED_KEY[provider as keyof typeof PROVIDER_TO_CRED_KEY];
  if (!credKey) {
    return Response.json(
      { error: `Unknown provider: ${provider}` },
      { status: 400 },
    );
  }

  const result = await neurolink.generate({
    input: { text: prompt },
    provider,
    credentials: {
      // This example uses { apiKey: tenantApiKey } which works for API-key providers.
      [credKey]: { apiKey: tenantApiKey },
    } as NeurolinkCredentials,
  });

  return Response.json({ text: result.content });
}

Note: This example assumes API-key authentication. Providers like Bedrock (which use accessKeyId/secretAccessKey) and Ollama (which use baseURL) require different credential shapes — see the Provider Credential Reference above.

Limitations

1. CLI does not support --credentials — passing API keys as CLI flags would expose them in shell history, process lists, and log aggregators. Use environment variables for CLI usage instead.

2. No credential rotation within a streaming call — credentials are resolved once when generate() or stream() is called; you cannot swap keys mid-stream.

3. No built-in secret storage — NeuroLink passes credentials directly to the underlying provider SDK. Key storage, rotation, and encryption are the caller's responsibility. Consider integrating with a secrets manager (AWS Secrets Manager, HashiCorp Vault, Passetto) before injecting credentials into calls.

4. Ollama accepts only baseURL — Ollama does not use API keys; only the endpoint URL can be overridden.

5. Unrecognised fields are silently ignored — each provider only reads the fields documented in the reference table above. Passing extra fields has no effect.

6. Internal fallback switches providers — When a provider call fails and NeuroLink's internal fallback activates (selecting a different provider), the per-request credentials scoped to the original provider do not apply to the fallback provider. The fallback provider resolves credentials from its own instance-level or environment-variable sources. If you need strict per-call credential control and want to prevent fallback provider switches, set disableInternalFallback: true on the stream/generate call.

Key Files

File	Purpose
src/lib/types/providers.ts	NeurolinkCredentials type definition
src/lib/types/configTypes.ts	NeurolinkConstructorConfig.credentials field
src/lib/types/generateTypes.ts	GenerateOptions.credentials + TextGenerationOptions.credentials fields
src/lib/types/streamTypes.ts	StreamOptions.credentials field
src/lib/factories/providerFactory.ts	Per-provider credential slice extraction
src/lib/factories/providerRegistry.ts	All 13 provider factory registrations
src/lib/neurolink.ts	resolveCredentials() merge helper + generate()/stream() threading

See Also

• Authentication Providers -- token validation, RBAC, and session management for your own API endpoints
• Observability Guide -- tracing generate/stream calls. Credentials are passed only to the underlying provider SDK, not captured in NeuroLink span attributes; if you attach custom span enrichment, avoid logging the credentials field.
• SDK API Reference -- complete SDK reference