---
title: "STORE: persist a JSON value under a key, scoped to YOUR..."
method: POST
path: "/api/store/kv-put"
tags: ["store"]
---

# STORE: persist a JSON value under a key, scoped to YOUR...

`POST /api/store/kv-put`

## Request

- Base URL: `https://2s.io`
- URL: `https://2s.io/api/store/kv-put`
- Auth: API key in header `PAYMENT-SIGNATURE`

STORE: persist a JSON value under a key, scoped to YOUR wallet (the x402 payer). Key/value store with retrieval — set a value once, read it back later with store.kv-get or list with store.kv-scan. Data is private to your wallet and kept on a rolling 90-day window that resets every time you touch the object. Use a namespace (ns) to group related keys. Value up to 1 MB; 50 MB total per wallet across kv/documents/vectors/files. No account or API key — pay per call with x402 and your data is keyed to your payer address.

## Request body

- object
  - `ns` string, required: Namespace to group keys, 1-64 chars of [A-Za-z0-9._:-]. e.g. "memory" or "session:42".
  - `key` string, required: Key within the namespace, up to 256 chars of [A-Za-z0-9._:/-].
  - `value` unknown

## Other responses

- `200` (unresolved $ref)
- `400`: Invalid request — not charged. error.code: BAD_REQUEST or INVALID_PARAM (parameter validation; error.details.issues lists each problem), MALFORMED_JSON, or a request-specific code. Other client errors: 405 METHOD_NOT_ALLOWED (wrong verb; see the Allow header), 413 PAYLOAD_TOO_LARGE.
- `402`: Payment required. Body is the x402 PaymentRequirements envelope with a multi-network accepts array; the per-call price is in accepts[].amount (and on the operation as x-2s-price). Sign for whichever rail you hold USDC on (EIP-3009 for Base, partial SPL transfer for Solana) and retry with the PAYMENT-SIGNATURE header (X-PAYMENT also accepted for v1 clients). Also PAYMENT_SETTLE_FAILED (error envelope) when a verified payment failed to settle: error.details.chargeStatus is "not_charged" (retry with a fresh payment) or "unknown" (the authorization may still settle before its deadline — check it before retrying).
- `429`: Too many requests — RATE_LIMITED: our per-IP / per-payer limiter. Not charged; retry after Retry-After.
- `5XX`: Server-side failure. 500 INTERNAL: unexpected error; quote error.errorId (also the X-2s-Error-Id header). 502 UPSTREAM_UNAVAILABLE (or another UPSTREAM_* code): the data provider failed — composite endpoints refuse unbilled when every source fails. 503 SERVICE_PAUSED: endpoint paused by the operator kill switch, retry after Retry-After; 503 SPEND_CAP: daily upstream budget exhausted. 504 UPSTREAM_TIMEOUT. Not charged.

---

[API](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api.md) · [All operations](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/llms.txt) · [OpenAPI document](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/revisions/da4c5caf686e?raw)