# Delx Commerce — Seeded Multivariate Assignment

> Delx Commerce — Seeded Multivariate Assignment is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Deterministically assigns a subject to one of N weighted variants using a seed, returning the selected variant and its index with cryptographic evidence of no data retention.

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/seeded-multivariate-assignment?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-commerce-seeded-multivariate-assignment-0b9ed32a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4yDXznqqDh-wuG-JrAzaE

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 delx-commerce-seeded-multivariate-assignment-0b9ed32a -d '<json body>'
```

Example prompt: For user ID 'user-8821', use seed 'exp-launch-v3' and assign them to one of three variants — 'control', 'copy-a', 'copy-b' — with weights 50, 25, 25.

## When to prefer this

Choose this endpoint when you need deterministic, reproducible variant assignment — i.e. the same seed+subject combination must always yield the same variant — without storing any user data server-side. It is ideal for AI agents running experiments or feature flag logic that require verifiable, auditable decisions with cryptographic proof of no retention. Prefer it over stateful experimentation platforms when zero data retention and pay-per-call billing (no subscription) are priorities.

## Known failure modes

- Mismatched variants and weights array lengths causing validation error
- Weights summing to zero leading to undefined selection
- Seed or subject strings exceeding 8192 character limit
- Variants array exceeding 256-item limit causing rejection
- Payment failure over x402 protocol blocking the request
- Malformed JSON body returning a 400-level error

## How this service works

Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.

## Output

Returns a JSON object with the selected variant name and its index in the variants array, plus cryptographic evidence including an SHA-256 hash of the input and confirmation that no data was retained and zero external calls were made. The schema identifier and operation name are also included for auditability.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "seed": {
   "type": "string",
   "maxLength": 8192,
   "description": "Seed supplied to Seeded Multivariate Assignment; used only for this bounded calculation and processed in memory without retention."
  },
  "subject": {
   "type": "string",
   "maxLength": 8192,
   "description": "Subject supplied to Seeded Multivariate Assignment; used only for this bounded calculation and processed in memory without retention."
  },
  "weights": {
   "type": "array",
   "items": {
    "type": "number"
   },
   "maxItems": 256,
   "description": "Weights supplied to Seeded Multivariate Assignment; used only for this bounded calculation and processed in memory without retention."
  },
  "variants": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Variants supplied to Seeded Multivariate Assignment; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "index": 2,
   "variant": "copy-b"
  },
  "schema": "delx/util-seeded-multivariate-assignment/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "d4cc54b28dc2c9127391313e2d1f0fdfeb7409cb441c2107a91ae423c62cc39c",
   "external_calls": 0
  },
  "operation": "seeded_decision:seeded_multivariate_assignment"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-seeded-multivariate-assignment-0b9ed32a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from commerce.delx.ai](https://www.zero.xyz/host/commerce.delx.ai/llms.txt)