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Delx Choice Index
x402
Delx Choice Index is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).
Deterministically maps a seed string into an integer index within [0, length) for stable, stateless A/B or bucket assignment
Price / call$0.001
Success—
StatusUnknown
How this service works
Deterministic index from seed into [0,length). Call when you need stable A/B assignment without shared RNG state. Returns index, length, ok for $0.001 USDC via x402 on Base. No network, no keys, no retention; first-party local JSON only. Results are advisory; the caller owns budgets, auth, and production controls.
Output
Returns a JSON object with an integer `index` in [0, length), the `length` that was passed in, and an `ok` boolean confirming success. The index is fully deterministic for any given seed and length pair, with no retained state or randomness.
Example use cases
A/B test variant assignment
“I need to deterministically assign user ID 'usr_8821' to one of 3 experiment variants — always the same variant for that user — can you get the bucket index using that as the seed with length 3?”
Stable content shard routing
“I have 8 content shards and need to route request key 'req-2024-abc' to a consistent shard every time without any shared state — what index does that seed map to across 8 options?”
Reproducible feature flag selection
“For a reproducible feature flag rollout, map the seed 'tenant-corp-7' deterministically to one of 5 feature tiers and tell me which tier index it lands on.”
Technical details
Endpoint
POSThttps://api.delx.ai/api/v1/x402/choice-indexWhen to prefer
Choose this endpoint when you need stable, reproducible bucket or variant assignment from a string key without any shared random number generator state, database lookups, or external dependencies. It is ideal for distributed agent systems where multiple nodes must agree on the same assignment for a given seed, for A/B testing without a central experiment service, or for any deterministic routing/sharding use case where idempotency and zero side effects are required.
Side effects
- Missing or empty seed string returns an error or ok:false
- Length of 0 or negative integer causes invalid range error
- Non-integer length value causes a schema validation failure
- Network timeout on the paid x402 endpoint results in no response
- Payment failure via x402 protocol blocks the request before computation
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| seed | string | Input field: seed. |
| length | integer | Input field: length. |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"index": 3,
"length": 5,
"schema": "delx/util-choice-index/v1"
}
}Tags
x402
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