# MoMo > MoMo is Vietnam's largest mobile-money and e-wallet platform, operated by Online Mobile Services Joint Stock Company ("M_Service"), founded 2007 and licensed by the State Bank of Vietnam. Its merchant business publishes four public APIs: the All-in-One (AIO v2) Payment Gateway, a Business Page OpenAPI, a Voucher Distribution API and a Mini App Open Platform. Generated by API Evangelist on 2026-08-26 from MoMo's public developer surface. MoMo does not publish an llms.txt of its own (probed /llms.txt on eight MoMo hosts, all 404 or SPA shell). Important facts for an agent working with MoMo: - There is NO OpenAPI, Swagger, AsyncAPI, protobuf or WSDL. The most machine-readable artifact MoMo publishes is a set of 14 public Postman collections covering 67 requests. - Every AIO v2 operation is an HTTP POST, including the read operations (query, refund/query). Content-Type is application/json; charset=UTF-8. - Every request carries an HMAC-SHA256 `signature` over an alphabetically ordered key1=value1&key2=value2 string built from a per-operation field list. The secretKey must never leave the merchant server. - Idempotency is real: `requestId` in the request BODY (not a header), unique per company account, honoured for at least 31 days. A duplicate in flight returns HTTP 422 with resultCode 7000. - Errors are a numeric `resultCode` plus a localised `message` in an ordinary JSON body — not RFC 9457 problem+json. - Results are pushed back over IPN to the `ipnUrl` supplied in the create request. The merchant must answer HTTP 204 within 15 seconds and must verify the signature. - No rate limits, no rate-limit headers, no 429 semantics are published anywhere. - No status page, no SLA, no deprecation policy. Withdrawn API versions are discovered at runtime via resultCode 12. - Refunds are reversible with published amount bounds; DISBURSEMENTS ARE NOT REVERSIBLE — MoMo publishes no recall or clawback operation. ## APIs - [MoMo All-in-One Payment Gateway (AIO v2)](https://developers.momo.vn/v3/docs/payment/guides/payment-with-aio/): wallet, ATM card, credit card, Apple Pay, Google Pay, Buy Now Pay Later, QR and POS acceptance, tokenisation, subscriptions, disbursement. Base https://payment.momo.vn/v2/gateway/api (test https://test-payment.momo.vn). - [MoMo Business Page OpenAPI](https://developers.momo.vn/v3/docs/business-page/overall/): manage MoMo Business Pages, posts, reviews, customer segments, care messages and page reports. Base https://business.momo.vn/api (UAT https://uat-business.momo.vn/api). Auth: Partner Id + X-API-KEY. - [MoMo Voucher Distribution API](https://developers.momo.vn/v3/docs/voucher-distribution/overall/): create promotion campaigns, upload voucher codes, reconcile redemptions. Base https://business.momo.vn/api. Auth: clientId/clientSecret exchanged for a 24-hour bearer token; X-Request-Id UUID required. - [MoMo Mini App Open API](https://developers.momo.vn/v3/docs/app-center/development-guideline/components-api-sdk/open-api/api-specifications/): server-to-server API for Mini Apps — access tokens, user profile under consent, push notifications. Base https://openapi.momo.vn/gateway/open/v1. Auth: JWT bearer + OP-Signature (SHA256withRSA) + M-Timestamp. ## Core reference - [Integration Procedures](https://developers.momo.vn/v3/docs/payment/onboarding/integration-process/): environments, credentials, timeouts, IP allowlists. - [Wallet one-time payment](https://developers.momo.vn/v3/docs/payment/api/wallet/onetime/): the canonical create-payment reference. - [Confirm Payment (capture / cancel)](https://developers.momo.vn/v3/docs/payment/api/payment-api/confirm/) - [Reverse & Refund](https://developers.momo.vn/v3/docs/payment/api/payment-api/refund/) - [Check Transaction Status](https://developers.momo.vn/v3/docs/payment/api/payment-api/query/) - [Single Disbursement](https://developers.momo.vn/v3/docs/payment/api/disbursement-v2/) and [Batch Disbursement](https://developers.momo.vn/v3/docs/payment/api/bulk-disbursement-v2/) - [Digital Signature (HMAC-SHA256)](https://developers.momo.vn/v3/docs/payment/api/other/signature/), [RSA](https://developers.momo.vn/v3/docs/payment/api/other/RSA/), [AES](https://developers.momo.vn/v3/docs/payment/api/other/AES/) - [API Idempotency](https://developers.momo.vn/v3/docs/payment/api/result-handling/idempotency/) - [List Result Codes](https://developers.momo.vn/v3/docs/payment/api/result-handling/resultcode/) - [Payment Notification (IPN)](https://developers.momo.vn/v3/docs/payment/api/result-handling/notification/) - [Bank Codes List (NAPAS 970xxx)](https://developers.momo.vn/v3/docs/payment/api/result-handling/bankcode/) - [Test Instructions](https://developers.momo.vn/v3/docs/payment/onboarding/test-instructions/) - [Postman collections](https://developers.momo.vn/v3/docs/payment/api/other/postman/) ## Tooling - [GitHub: momo-wallet](https://github.com/momo-wallet): payment examples, PHP SDK, Java SDK, mobile SDK. - PHP SDK: `composer require mservice/payment` (dev-master only, last updated 2022-02-18). - Java SDK: `io.github.momo-wallet:momopayment:1.0` on Maven Central (published 2019-07-16). - Mini App CLI: `npm i @momo-miniapp/cli -g` — NOT on the public npm registry; requires an NPM configuration copied from the Mini App dashboard. - Component Kits v2: `npm install @momo-kits/core` (React Native, for Mini Apps). ## API Evangelist artifacts - [apis.yml](apis.yml) - [Authentication](authentication/momo-authentication.yml) - [Conventions, idempotency and reversibility](conventions/momo-conventions.yml) - [Error codes](errors/momo-error-codes.yml) and [decline codes](errors/momo-decline-codes.yml) - [Webhooks / IPN catalog](asyncapi/momo-webhooks.yml) - [Sandbox and test instruments](sandbox/momo-sandbox.yml) - [Data model](data-model/momo-data-model.yml) - [Packages and SDKs](packages/momo-packages.yml) - [CLI](cli/momo-cli.yml) and [components](components/momo-components.yml) - [Conformance and compliance](conformance/momo-conformance.yml) - [Lifecycle](lifecycle/momo-lifecycle.yml) and [changelog](changelog/momo-changelog.yml) - [Plans and pricing](plans/momo-plans-pricing.yml) and [rate limits](rate-limits/momo-rate-limits.yml) - [Consent scopes](scopes/momo-scopes.yml) - [.well-known probe log](well-known/momo-well-known.yml) - [Postman collections (saved verbatim)](postman/_index.yml) - [MCP candidate surface](mcp/momo-mcp.yml) ## Commercial - [MoMo for Business (merchant portal / sign up)](https://business.momo.vn/) - [Terms and conditions](https://www.momo.vn/dieu-khoan-dieu-le) - [Privacy policy](https://www.momo.vn/chinh-sach-quyen-rieng-tu) - [Help centre](https://www.momo.vn/hoi-dap) - [Technical support](https://developers.momo.vn/v3/docs/app-center/technical-support/) — hotline 1900 636 652, merchant.care@momo.vn - No public pricing is published for any MoMo API.