# cryptoinfra — Custodial wallet API > cryptoinfra is custodial wallet infrastructure on TRON. Merchants create end-users, receive deposits on permanent per-user addresses, track balances in a double-entry ledger, and execute payouts, swaps and card issuance over one REST API. This documentation is generated from OpenAPI 1.0.0: 68 operations, 56 schemas, 9 webhook events. ## Guides - [Introduction](https://docs.cryptoinfra.net/md/introduction): What cryptoinfra is, how the custodial model works, and the shortest path from a new user to a paid-out balance. - [Quickstart](https://docs.cryptoinfra.net/md/quickstart): Your first deposit and your first payout in six calls — copy, paste, done. Everything else in these docs is detail you can read later. - [Authentication](https://docs.cryptoinfra.net/md/authentication): One bearer API key authenticates the merchant on every /v1 endpoint — except the public price sheet, a merchant's public affiliate ledger and the health checks. - [Static Wallet Address](https://docs.cryptoinfra.net/md/deposit-addresses): Assign each of your users one permanent TRON address that never rotates — every payment to it is credited to that user automatically, with no address generation per payment and no manual matching. - [Payouts](https://docs.cryptoinfra.net/md/payouts): Send money out of a user's balance to any address — quote the exact fee, create the payout with an idempotency key, learn the outcome from the webhook and confirm it with the read. - [Swaps and exchange](https://docs.cryptoinfra.net/md/swaps-and-exchange): Trade between two coins a user holds, or sell one and pay any of thousands of other coins out to an external address — quote, create, poll; there is no webhook. - [Cards, end to end](https://docs.cryptoinfra.net/md/cards-guide): The whole card flow in order — register the holder, verify identity, read the shelf, issue a funded card, show it, load it, watch it spend, and close it — with what each step charges and what to do when a call answers 202 or 503. - [Money and amounts](https://docs.cryptoinfra.net/md/money-and-amounts): Every amount is a decimal string paired with an exact integer *_base twin — why the pairing exists, where it is missing, and the rounding rules that are refusals rather than roundings. - [Idempotency](https://docs.cryptoinfra.net/md/idempotency): Every mutation that moves money takes an idempotency_key. What a replay returns, when a replay becomes a 409, and how to resolve a request whose outcome you never learned. - [Errors](https://docs.cryptoinfra.net/md/errors): One error envelope for the whole API, what each status class means for a retry, and the full catalogue of error responses generated from the contract. - [Webhooks](https://docs.cryptoinfra.net/md/webhooks): Every event cryptoinfra sends, how to verify the HMAC, how to survive at-least-once delivery — and the flows that emit nothing at all and must be polled. - [Fees and pricing](https://docs.cryptoinfra.net/md/fees): Every fee cryptoinfra charges, and for each one exactly which balance it comes out of — your customer's balance or the card itself. - [Fee calculator](https://docs.cryptoinfra.net/md/fee-calculator): Type an amount and read the exact deduction for a payout, a card load, a card issue or a deposit — every figure live from the public price sheet, nothing typed in. - [AI integration](https://docs.cryptoinfra.net/md/ai-integration): Machine-readable views of this documentation — llms.txt, llms-full.txt, per-page Markdown and a structured corpus — plus the facts an agent most often gets wrong about this API. - [Changelog](https://docs.cryptoinfra.net/md/changelog): Every change to this API and these docs, newest first — what changed, whether it breaks an existing integration, and what to do about it. ## API reference - [Users](https://docs.cryptoinfra.net/md/users): End-users and their Static Wallet Address — one permanent address per user, reused for every payment - [Balances & deposits](https://docs.cryptoinfra.net/md/balances-deposits): Read spendable balances and incoming deposit history - [Withdrawals](https://docs.cryptoinfra.net/md/withdrawals): Pay out from a user's balance - [Swaps](https://docs.cryptoinfra.net/md/swaps): Trade between two coins you hold — the output is credited to the user's balance - [Exchange](https://docs.cryptoinfra.net/md/exchange): Sell a coin you hold and pay any of several thousand others out to an address - [Cards](https://docs.cryptoinfra.net/md/cards): Crypto debit cards — holders, KYC, issuance, top-up/withdraw, reveal, and delivery - [Developer](https://docs.cryptoinfra.net/md/developer): Self-service integration plumbing — your webhook endpoints and their secrets, a test delivery, a log of recent API requests, and a live event stream. The API key itself is managed from the dashboard (Settings → API keys), not through the AP - [Reference](https://docs.cryptoinfra.net/md/reference): Asset catalogue, fee schedule, live prices - [System](https://docs.cryptoinfra.net/md/system): Health and metrics (no auth) - [Webhook events](https://docs.cryptoinfra.net/md/webhook-events): Payload reference for all 9 events cryptoinfra emits, generated from the OpenAPI contract. ## Optional - [Complete documentation in one file](https://docs.cryptoinfra.net/llms-full.txt): every page above, concatenated. - [Structured corpus](https://docs.cryptoinfra.net/corpus.json): the same pages as JSON, split into sections. - [Changelog feed](https://docs.cryptoinfra.net/changelog.json): every change, newest first, each flagged `breaking` or not. Poll this to tell whether an integration built against these docs still holds. Latest: v8.1.0 (2026-11-07).