# modelprices.xyz Cheapest 128k-Context LLM Leaderboard

> modelprices.xyz Cheapest 128k-Context LLM Leaderboard is a paid API for AI agents from modelprices.xyz, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Returns the 50 lowest-cost AI models with at least a 128,000-token context window, ranked by inference cost per token across 70+ providers, with input/output/cache pricing in USD per 1M tokens.

## Facts

- Endpoint: GET https://modelprices.xyz/llm/cheapest/128k-context
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/modelprices-xyz-cheapest-128k-context-llm-leaderboard-af1434ed
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_49Pbx4VthBXRXGuxe2TEI

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability modelprices-xyz-cheapest-128k-context-llm-leaderboard-af1434ed
```

Example prompt: Show me the 50 cheapest AI models that support at least a 128k context window, ranked by cost per token — I want to see input, output, and cache prices side by side so I can pick the most affordable one for processing long documents.

## When to prefer this

Use this endpoint when you need to identify the most cost-efficient LLMs specifically for long-document or large-context workloads (128k+ tokens). Prefer this over the general cheapest-model endpoint when context window size is a hard constraint, and over provider-specific pricing tables when you want a cross-provider comparison in a single call. Ideal for automated model-selection pipelines, cost optimization workflows, and budget-constrained LLM deployments.

## Known failure modes

- Service temporarily unavailable (503) if the pricing data feed is being refreshed
- Payment required error (402) if the $0.01 USDC per-call fee is not included
- Empty or reduced result set if fewer than 50 models currently meet the 128k context threshold
- Stale data risk within the hourly refresh window

## How this service works

Cheapest 128k-context LLM leaderboard: the 50 lowest-cost AI models with a 128,000-token context window or larger, ranked by inference cost per token across 70+ providers. Input, output and cache USD per 1M tokens with exact context window and capability flags joined in. The standard long-document tier, priced side-by-side. Refreshed hourly.

## Output

A ranked list of up to 50 AI models, each with: model name, provider, input cost (USD/1M tokens), output cost (USD/1M tokens), cache cost (USD/1M tokens), exact context window size, and capability flags. Data is refreshed hourly.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/modelprices-xyz-cheapest-128k-context-llm-leaderboard-af1434ed/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from modelprices.xyz](https://www.zero.xyz/host/modelprices.xyz/llms.txt)