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Delx Await Promise
x402
Delx Await Promise is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).
Creates a durable, paid promise that waits for a time or webhook condition, then releases an opaque continuation envelope with an Ed25519 receipt upon capability authorization.
Price / call$0.01
Success—
StatusUnknown
How this service works
Durable outcome promise for agents: pay $0.01 USDC once, wait for a time or signed webhook condition, then claim an opaque continuation envelope with an Ed25519 receipt. Idempotent replay, no subscription, no polling provider, and no continuation is exposed before the capability check.
Output
Returns a promise object containing a unique promise ID, the stored opaque continuation envelope (released only after the condition is met and capability is authorized), an Ed25519 cryptographic receipt confirming authenticity, and metadata about the condition and TTL. On idempotent replay with the same idempotency key, returns the identical promise and capability without re-charging.
Example use cases
Defer agent after payment approval
“I need to pause my agent right after submitting a payment and resume it once I get a webhook event with event type 'payment.confirmed' — store my continuation ciphertext and release it only after that event fires, using claim mode.”
Schedule overnight data pipeline resumption
“My data pipeline agent needs to sleep until tomorrow at 2025-08-01T06:00:00Z and then pick up where it left off — store the resume envelope now and let me claim it with a signed receipt at that exact time.”
Await external KYC verification webhook
“Hold my agent's continuation envelope until we receive an inbound webhook event of type 'kyc.approved', then release it via webhook delivery to https://myapp.example.com/resume so the agent can continue the onboarding flow.”
Technical details
Endpoint
POSThttps://api.delx.ai/api/v1/x402/awaitWhen to prefer
Choose this endpoint when an AI agent needs to durably suspend execution and resume only after a specific future time or an external event, without polling. It is ideal for long-running agentic workflows that require async checkpointing, secure continuation storage, and cryptographic proof of delivery. Prefer it over polling-based waits, cron jobs, or in-process timers when you need idempotent replay guarantees, a signed Ed25519 receipt, and zero exposure of the continuation before capability authorization. Best suited for x402-native agent pipelines that already handle micropayments.
Side effects
- Payment not received or x402 authorization fails — promise is not created
- TTL exceeds maximum of 604800000ms (7 days) — validation error
- Webhook delivery URL is missing when mode is set to 'webhook' — schema validation error
- Condition object does not match either 'time' or 'webhook' oneOf schema — rejected
- Resume envelope exceeds 32768 character limit — rejected
- Condition timestamp is in the past for time-based conditions — may result in immediate or error response
- Idempotency key collision with a different payload — conflict error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| ttl_ms | integer | |
| delivery | object | |
| condition | object | A future timestamp or an inbound event type. External HTTP polling is intentionally disabled. |
| idempotency_key | string | Stable client key. Replaying the same paid request returns the same promise and capability. |
| resume_envelope | string | Opaque client-owned continuation ciphertext. Delx stores and releases it only after capability authorization. |
Output
Schema · Response
{
"type": "json",
"example": {
"state": "waiting",
"schema": "delx/await/v1",
"receipt": {
"schema": "delx/await-receipt/v1",
"algorithm": "Ed25519"
},
"delivery": {
"mode": "claim",
"state": "claim_only",
"attempts": 0,
"event_id": null
},
"condition": {
"kind": "webhook",
"event_type": "build.completed"
},
"capability": "opaque-capability-returned-on-create",
"created_at": "2026-08-04T16:00:00Z",
"expires_at": "2026-08-04T17:00:00Z",
"promise_id": "123e4567-e89b-12d3-a456-426614174000",
"resume_envelope_sha256": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
}
}Tags
x402
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