---
title: "Create a Stripe PaymentIntent to buy mu by dollar amount at the peg"
method: POST
path: "/mu/purchase-intents"
tags: ["Mu"]
---

# Create a Stripe PaymentIntent to buy mu by dollar amount at the peg

`POST /mu/purchase-intents`

## Request

- Base URL: `https://api.mnemom.ai/v1`
- URL: `https://api.mnemom.ai/v1/mu/purchase-intents`
- Auth: HTTP bearer

Creates a Stripe PaymentIntent for the authenticated caller's organization to buy mu at the fixed peg (1 mu = 1¢, face-only retail — MNE-3255). Owner/admin only (`org_id` query targets a specific org; a non-member or under-privileged caller is denied 403). api resolves the org's `billing_account_id` server-side and authors the upstream body itself — a client-supplied account reference is never forwarded. `amountUsdCents` must be a JSON integer; the min/max purchase bounds are enforced by mnemom-billing (its 400 passes back verbatim). `idempotencyKey` is REQUIRED — billing scopes the Stripe idempotency key to it so a retry of the same purchase cannot double-charge. Response is mnemom-billing's verbatim `{paymentIntentId, clientSecret, expectedMmu}` on 201; `expectedMmu` is a display prediction, never mint authority — the ledger credits only when `payment_intent.succeeded` arrives on the webhook.

## Query parameters

- `org_id` string

## Request body

- object
  - `amountUsdCents` integer, required: Whole USD cents to charge. Bounds are enforced by mnemom-billing (MIN/MAX_PURCHASE_CENTS), not mirrored here.
  - `idempotencyKey` string, required: Caller-chosen retry key. billing composes the Stripe idempotency key from it, so re-submitting with the same key cannot double-charge.

## Response `201`

PaymentIntent created (mnemom-billing response, verbatim): `{paymentIntentId, clientSecret, expectedMmu}`.

- object

## Other responses

- `400`: Bad request
- `401`: Authentication required
- `403`: Forbidden
- `404`: Resource not found
- `409`: Resource conflict — the request cannot proceed because of a current state conflict (e.g., resource already exists, version mismatch, in-flight idempotency key with a different body).
- `429`: Rate-limit exceeded. The global per-IP limiter (100 requests/minute, applied to every `/v1/*` route) rejected this request. Back off until the window resets — `Retry-After` carries the cooldown in seconds and `X-RateLimit-Reset` the absolute reset time.
- `500`: Server error — request was well-formed but the server failed to fulfill it. Typically a downstream dependency (DB / RPC / external API) returned an unexpected error.
- `502`: An upstream dependency returned an invalid response.
- `503`: An upstream dependency is currently unavailable. The request was not processed; retry after the cooldown window.

---

[API](https://skmtc.dev/mnemom/apis/mnemom-api.md) · [All operations](https://skmtc.dev/mnemom/apis/mnemom-api/llms.txt) · [OpenAPI document](https://skmtc.dev/mnemom/apis/mnemom-api/revisions/274b7a6ea182?raw)