SmartX Trading API

Unofficial. Community notes, not published by SmartX.

Place and manage prediction-market orders on SmartX from your own code.

SmartX runs the execution side for you. You send an intent (which outcome, which side, what price, how much) and the platform signs and submits it, so there is no wallet plumbing, no gas handling, and no key management in your client.

Everything here was verified against the live API on 2026-08-10, on two accounts, including the parts that behave oddly. Start with Authentication, then Orders.

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What you can do today

Place an order	limit or market, buy or sell, sized in USDC
Cancel an order	one at a time, and always verify. See Orders
List your orders	with fill state, average price, and failure reasons
List your positions	shares, entry, mark, realised and unrealised PnL
Inspect one market	your position in a single market
Read market data	prices and outcome ids for any listed market

| Measure your balance | there is no endpoint, so examples/check-balance.mjs works it out. See Positions |

Quickstart

Node 18 or newer, no dependencies to install.

git clone https://github.com/bitgett/smartx-trading-api-docs
cd smartx-trading-api-docs

export SMARTX_TOKEN="jwt eyJ..."      # see docs/authentication.md
node examples/list-positions.mjs

If that prints your positions, you are connected.

Three things to know before your first order, each of which has surprised someone already:

1. The minimum order is 5 shares, so the minimum spend scales with price. At a 2c limit that is $0.10; at 50c it is $2.50. Below it you get 60307 limit order shares must be >= 5.
2. usdc_budget sets your size, share_amount is ignored. Read the real size back off the order afterwards.
3. 200 means accepted, not filled. Orders can fail later, asynchronously.

All three are in Orders, which is worth reading in full before you send anything with real size behind it.

Base URL

https://api-grey.smartx.io

Two families live under it:

• /service/poly_trade/… — your account: orders, positions
• /analytics/api/v1/… — market and wallet data, read only

Every response uses the same envelope

{ "code": 200, "msg": "success", "data": { } }

code is the one to branch on, not the HTTP status: a request can return HTTP 200 with code set to an error.

⚠️ Success is 200 under /service/… and 0 under /analytics/…. Both say msg: "success". Accept both or half the API will look broken. See Errors.

Contents

• Authentication
• Orders
• Positions
• Markets
• Errors
• Examples

Before you go live

Read Orders. The one that has actually cost money is treating 200 as a fill: the order can fail later, the client never hears about it, and it keeps sizing the next order against money it no longer has.

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Maintained independently of SmartX. The API can change without this repo knowing, so if the docs and the API disagree, the API is right. Open an issue and it gets fixed.