Upstage Provider Guide

Upstage is a Tier-2 catalog provider: OpenAI-wire-compatible with no behavioural quirks, so its entire integration is one JSON file (src/lib/providers/catalog/upstage.json) rather than hand-written code. That file is the source of truth for everything on this page.

Key Facts

Provider id: upstage (aliases: solar)
Protocol: OpenAI-compatible (/chat/completions)
Base URL: https://api.upstage.ai/v1
Default model: solar-pro4
Models in catalog: 10
Streaming: supported
Tool calling: supported (native)
Structured output: supported
Embeddings: not supported
Billing: free-tier
Key format: ^up_[A-Za-z0-9]+$

Quick Start

1. Get an API key

Visit: https://console.upstage.ai (Google OAuth works)
New accounts get a $10 sign-up credit — no payment method required
Create an API key under API Keys
Set UPSTAGE_API_KEY in your .env file

2. Configure

export UPSTAGE_API_KEY=your-api-key
export UPSTAGE_MODEL=solar-pro4      # optional — overrides the default model
export UPSTAGE_BASE_URL=https://api.upstage.ai/v1   # optional — self-hosted or proxy

3. Use it

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

const neurolink = new NeuroLink();

const result = await neurolink.generate({
  input: { text: "Explain context windows in one paragraph." },
  provider: "upstage",
  model: "solar-pro4",
});

console.log(result.content);

# CLI
npx @juspay/neurolink generate "Hello" --provider upstage

Per-request credentials work as they do for every provider:

await neurolink.generate({
  input: { text: "Hello" },
  provider: "upstage",
  credentials: { upstage: { apiKey: process.env.UPSTAGE_API_KEY } },
});

Models

Model	Context	Vision	$/M in · out	Notes
`solar-pro4` ⭐	512K	no	$0.3 / $1.2	Solar Pro 4; 512K context, up to 128K output tokens; agentic flagship for tool calling, terminal tasks and long-document reasoning
`solar-pro4-260806`	512K	no	$0.3 / $1.2	Pinned dated snapshot of Solar Pro 4 (2026-08-06 build) — the id the solar-pro4 alias currently resolves to
`solar-pro3`	512K	no	$0.15 / $0.6	Solar Pro 3; drop-in replacement for Solar Pro 2 with the same API interface, throughput and latency
`solar-pro3-260323`	512K	no	$0.15 / $0.6	Pinned dated snapshot of Solar Pro 3 (2026-03-23 build)
`solar-pro2`	512K	no	$0.15 / $0.6	Solar Pro 2; 31B-parameter model with an optional Reasoning Mode
`solar-pro2-251215`	512K	no	$0.15 / $0.6	Pinned dated snapshot of Solar Pro 2 (2025-12-15 build)
`solar-mini`	512K	no	$0.15 / $0.15	Solar Mini; small, fast model for lightweight reasoning and cost-efficient tasks
`solar-mini-250422`	512K	no	$0.15 / $0.15	Pinned dated snapshot of Solar Mini (2025-04-22 build)
`syn-pro`	512K	no	—	Syn Pro; Upstage's Japan-focused LLM
`syn-pro-251021`	512K	no	—	Pinned dated snapshot of Syn Pro (2025-10-21 build)

Fallback order when the default is unavailable: solar-pro3 → solar-mini.

Verification status

Tier-2 onboarding requires evidence before a provider is accepted, and pnpm run verify:provider-onboarding gates it in CI. This is what the catalog records for Upstage:

Probe	Result
Roster	authenticated GET /v1/models, HTTP 200, 2026-09-03
Auth rejection	HTTP 401 `invalid_api_key`, 2026-09-03
Live capability sweep	not run

⚠️ No live capability sweep is recorded for Upstage. The roster and auth behaviour were verified against the real API on the date above, but the capability flags come from the catalog declaration rather than from a measured end-to-end run. Treat them as the provider's stated behaviour.

Troubleshooting

Symptom	Cause	Fix
`Invalid Upstage API key`	`UPSTAGE_API_KEY` unset or wrong	Check the key at https://console.upstage.ai/api-keys
Model not found	The roster changed since 2026-09-03	Pick a current id; catalog providers retire models without notice

Key Facts​

Quick Start​

1. Get an API key​

2. Configure​

3. Use it​

Models​

Verification status​

Troubleshooting​

See also​