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self-custody escrow-options · XRP Ledger
FILE 01 · LANDING
2026-04-27

caput.dev

The self-custody option.
Your assets never leave your wallet.

Every options market ever built requires you to give up custody of your assets — to an exchange, a protocol, a pool, a desk. caput doesn't. The seller deposits into escrow on the XRP Ledger. The buyer locks margin and premium into escrow. Both wallets retain signing authority for the entire term. The AMM settles. No intermediary holds assets at any point. Self-custody escrow-options. The first of their kind.

↳ scroll for the schematic BSL 1.1 · source on agreement
FIG. 01
POSITION
ANATOMY
cross-section / seller side
DIAG-A77
scale 1:1
BUYER · WALLET rN7n… XRP balance 10,000.00 [01] swap XRPL · AMM POOL XRP/RLUSD spot 0.5421 depth 4.2M [02] convert XRPL · TOKEN ESCROW RLUSD CONVERTED 5,421 PRINCIPAL · LOCKED BUYER MARGIN 1,000 10% · STOP-LOSS FINISHAFTER · 15D PREMIUM 300 RLUSD [03] premium · 3% SELLER · WALLET r9pk… seller · locked 15d no exit · auto-release [04] collateral T+15D · EXPIRY finish-after release ⚠ 90% SOFT co-signed ⚠ 100% HARD automatic
A · TENOR
15d
B · PREMIUM
3%
C · MARGIN
10%
REF-01 · TENORFIXED ENUM
5/10/15/30
day terms · seller picks one
REF-02 · STATENO TOP-UPS
LOCKED// once
no margin calls · no add-ons
REF-03 · SAFETYTWO TIERS
90%/100%
soft co-signed · hard automatic
REF-04 · OPSYOUR INFRA
SELF// hosted
your keys · your trade · your tool
SECTION 01.5 IN PLAIN ENGLISH

What this actually is.

The custody problem

Every options market requires custody transfer. An exchange holds your deposit. A DeFi protocol locks your tokens in a smart contract. An OTC desk uses a third-party escrow agent. In all cases, your assets leave your control and you trust an intermediary to return them. That intermediary is the source of every structural risk in derivatives — insolvency, exploit, admin key compromise, withdrawal freezes.

The self-custody option

caput eliminates the intermediary. Your assets go into escrow on the XRP Ledger — a ledger object, not a protocol, not a smart contract, not a pool. Your wallet remains the only signing authority. The escrow enforces timing and conditions. The 2-of-2 multisig enforces bilateral agreement. Custody never transfers. The ledger is the clearinghouse.

The seller creates the market

The seller deposits an asset and locks it for a fixed term. By doing so, they create a market opportunity that would not otherwise exist. In return, the seller earns premium — income for providing the market and for the duration their capital is locked. The seller's deposit is returned at settlement. This is not a directional position — the seller is compensated for creating the market and managing the risk of doing so.

The buyer accesses the opportunity

The buyer pays a fee (premium) to participate in the market the seller created. They lock margin — defined risk capital with a known maximum loss. In return, the buyer gains access to directional exposure on XRP/RLUSD with uncapped upside. This is not about one party winning at the other's expense. The seller earns income for providing the market. The buyer pays for the opportunity to participate in it. Both parties are managing risk.

No winners and losers

In a self-custody option, the seller is not hoping the buyer fails. The buyer is not hoping to take the seller's deposit. The seller created a market and was paid for it. The buyer accessed that market and paid a fair fee. At settlement, the AMM determines the outcome based on what actually happened in the market. The seller is made whole. The buyer's margin absorbs any shortfall, or the buyer receives any surplus. Both outcomes are the contract working as designed — not one party defeating the other.

What you're buying from us

A binary. Software you download once and run on your own infrastructure. We sell it for XRP. After the purchase, we're out of the picture — we don't host, don't custody, don't participate in your contracts, and don't provide ongoing service. You own the tool. The architecture is described in full in the self-custody option paper.

SECTION 02 THE PROBLEM three frictions, one missing primitive

Two parties. No primitive.

02·A
CEX centralized exchanges
FIG·02A VENUE · CUSTODIAL USER FUNDS · POOLED YOU VENUE cross-section

Custody is the cost.

Centralized options exchanges hold your funds, your keys, your terms, and your counterparty risk. You're trading with the venue, not against another participant. Withdrawals queue at someone else's discretion.

02·B
OTC direct desks
FIG·02B PARTY A PARTY B LEGAL + ESCROW + SETTLEMENT overhead·illustrated

Bilateral is friction.

Direct OTC works for desks moving eight figures. For everyone else, the legal, escrow, and settlement overhead eats any premium worth collecting. Trust assumptions multiply on every contract.

02·C
DEFI synthetic options
FIG·02C LIQUIDITY POOL ·SYNTHETIC· ORACLE no writer no handshake pool·dependency

Synthetics aren't trades.

Most on-chain options are token-wrapped synthetics with pool counterparties and oracle dependencies. The "option" is a yield product. There is no seller on the other side, no fixed counterparty, no real handshake.

SECTION 03 HOW IT WORKS one agreement, four states, three exits

One agreement.
Then it's done.

FIG. 03 · POSITION LIFECYCLE
SCHEMATIC · CROSS-SECTION
REF-LC-15D · 3% · PUT
all states shown · scale 1:1
T-0 T+5 T+10 T+15 EXP REF-DEP · DEPLOY SIGN · LOCK both parties · atomic premium → seller funds → escrow POSITION · LIVE · LOCKED 90% FLOOR EXIT-A · BUYER ONLY VOLUNTARY close · anytime · current rate EXIT-B · BOT TRIGGER LIQUIDATE 90% loss · 10% buffer back EXIT-C · TIME EXPIRY FinishAfter auto-release on-ledger SELLER · LOCKED · NO EXIT · PREMIUM RECEIVED · COLLATERAL HELD [TIMELINE BAND]
01REF-DEP

Sign and lock.

Both parties sign the deploy bundle in their own wallets. Premium pays. AMM converts. Escrows lock. Atomic — all or nothing.

multi-tx · linked option_id
02REF-LV

Position lives.

The clock runs. Bot polls AMM. Mark-to-market computed every ledger. Buyer can exit. Seller cannot.

~12s poll · on-chain price
03REF-XT

Four ways out.

Buyer voluntary close. Soft liquidation at 90% (both co-sign). Hard liquidation at 100% (automatic, pre-signed). Or expiry hits and settlement fires.

close · soft liq · hard liq · expire
04REF-DN

Settlement.

AMM swaps back. Funds resolve to whoever's owed. Bot updates min-count log. Position is caput.

on-ledger · auditable
SECTION 04 · THE OPPORTUNITY

One card.
One handshake.

This is the entire seller-to-buyer interface. The seller publishes terms. The buyer imports the invitation, picks their margin, accepts. Both sign in their own wallets. Funds lock atomically. The clock starts ticking.

No order book. No matching engine. No platform between you. The card is the trade.

SCHEMA · SIGNED OPPORTUNITY
option_id0x77a2…1c4f
sideput
notional10,000 RLUSD
premium_pct3
tenor_days15
amm_refXRP/RLUSD canonical
seller_addrrN7n…3kQp
offer_expiresT+24h
signatureed25519 · valid
REF-77A2 · INCOMING OPPORTUNITY SIGNED OFFER
PUT · WRITER SIDE
10,000RLUSD
FROM
rN7n…3kQp
offer expires
23:47:12
premiumA·01
3%
300 RLUSD · paid at deploy
tenorA·02
15d
FinishAfter · auto-release
liquidationA·03
90% / 100%
soft co-signed · hard automatic
sideput · bearish XRP
amm referenceXRP/RLUSD canonical
premium owed300 RLUSD
spot at offer0.5421
notional in xrp≈ 18,447
slippage est~0.18%
PICK YOUR MARGIN REF-MARGIN · ENUM
you lock1,000 RLUSD
max loss1,300 RLUSD
your tx count3 sigs
est gas~150 drops
SECTION 05 DISCLOSURE what this is and isn't

Not custodial.
Not for everyone.

×
REF-D1 · NOT A SERVICE

You bought a binary.

caput sells software, once, for XRP. After that we are not on the other end of anything. No accounts, no logins, no support tickets, no SLA. You run the bot. You sign every transaction. Whatever happens after deploy is between you, your counterparty, and the XRPL.

×
REF-D2 · NOT CUSTODIAL

We never hold anything.

The bot constructs transactions. You sign them in your own wallet — Xaman, hardware, whatever you use. Funds move from your address to escrow contracts you co-control with your counterparty. We have no signing authority. We can't freeze. We can't recover.

×
REF-D3 · NOT NO-RISK

This is leverage. It can go to zero.

Your full locked margin may be consumed. The 10% buffer is a buffer, not a guarantee. There are no top-ups. The seller is locked in for the full tenor. If the AMM you reference moves against you and stays there, you will be liquidated. Don't lock what you can't lose.

×
REF-D4 · NOT ADVICE

Read the source. Then decide.

The source ships under BSL 1.1 and converts to Apache 2.0 after four years. Audit the binary or the source before you run it. Run an LLM over it. Check the hash. We're not your lawyer, your broker, or your counterparty. We're a tool.

SECTION 06 DEPLOYMENT TARGETS run it your way · your infra

Your infrastructure.
Your keys.

06·A
DEPLOY-RWYrecommended

Railway

One-click deploy from GitHub. Persistent process, simple billing. About five dollars a month. Sane default.

typePaaS
cost~$5/mo
setup5 min
06·B
DEPLOY-FLYmulti-region

Fly.io

Small VMs, cheap, multi-region. Good for users who want geographic redundancy or want to be near a specific XRPL cluster.

typeVM
cost~$3/mo
setup10 min
06·C
DEPLOY-RNDfree tier

Render

Free tier for hobby use, paid for serious. Same shape as Railway, different host. Good fallback choice.

typePaaS
costfree / $7
setup5 min
06·D
DEPLOY-OWNfull control

Self-host

Docker image runs anywhere with outbound network. Raspberry Pi, NAS, home server, any VPS. Total sovereignty.

typedocker
costyour call
setup15 min
SECTION 06.5 HELP + DOCS

Questions? Answered.

Q&A
COMMON QUESTIONS

How it works, simply.

What is this? How do I make money? What's my maximum loss? What do I pay? Can I close early? How do I know the seller won't cheat? Do I need to install anything?

read the Q&A →
CFG
CONFIGURATION

Every setting, explained.

Environment variables, bootstrap flow, wallet setup, host-specific deployment, contract defaults, changing config after launch.

read configuration →
FIX
TROUBLESHOOTING

Something broke? Start here.

Organized by symptom. Startup problems, deploy failures, runtime issues, settlement errors, wallet problems, recovery procedures.

read troubleshooting →
SECTION 07 · BAKE YOUR BUNDLE

Use your head.And have it done.

Pick your tier, configure your bot, pay in XRP, download the binary. Then we're done.

build your bot → read the source