Overview
What justi.fun is, the rules every coin follows, and every fee in full.
What justi.fun is
justi.fun is a Solana launchpad on Meteora's Dynamic Bonding Curve. Anyone can launch a coin. Every coin trades on its own bonding curve, and when the curve fills it moves to a Meteora DAMM v2 pool with its LP locked. The same rules apply to every coin, and they are set on chain or checked by the server before anything is signed.
This section is for builders: trading bots, wallets, terminals, launch tools, Telegram and Discord apps, and AI agents. Everything the site does is open through the API.
Why build on it
- One call to launch.
POST /v1/launchesbuilds the create transaction with the site's rules. You sign it and we send it privately through Jito. - Trading without SDK work on your side. Quotes and swaps work on the curve and after graduation on DAMM v2. The server simulates every swap and sets the compute limit and priority fee.
- No key needed to start. Anonymous calls work. A free key comes from a wallet signature in one request.
- Real time. Signed webhooks with retries, a WebSocket with channels per coin, and Server-Sent Events.
- Typed and described. An OpenAPI 3.1 spec, a zero-dependency TypeScript SDK, an MCP server for agents, and llms.txt.
- No extra fee for builders. A swap or launch built through the API pays exactly what it pays on the site.
Fair launch rules
| Rule | How it works |
|---|---|
| Server-built creates | The create transaction is built on the server and only signed by the creator. It is sent through Jito as a bundle-only transaction, so it lands without passing through the public mempool first. |
| 5 second sniper window | Trading opens at a 50% fee that steps down each second to the coin's normal fee. The extra is burned and shared as shown below. |
| Dev buy cap | A dev buy rides in the create transaction and is capped at 15% of supply. |
| Copy rule | A launch is refused only when the same ticker, name, image, website and X link were all used in the last 24 hours. Change any one and it goes ahead. |
| Launch limit | 10 launches per wallet per day. |
| Vanity mints | Coins get a mint ending in ...JUST from the server's pool, or a custom mint the creator brings. |
Safety facts
Set by the Meteora program on every coin, and returned on each coin by the API under safety:
Fixed 1B supplyMint authority revokedNo freeze authorityMetadata lockedLP 100% locked at graduation
Creator and holder rewards
| Mode | Who earns | Creator rate |
|---|---|---|
creator | The creator, claimed from the pool with their own wallet. | 0 to 2.5%, steps of 0.25% |
holders | Holders, 0.5% of volume paid in SOL every 10 minutes. | 0 |
split | Both: 0.5% to holders plus the creator's rate. | 0.25 to 2%, steps of 0.25% |
Fees in full
Live from GET /v1/pad. Percentages are of the SOL side of each trade.
| Fee | Where it goes |
|---|---|
| Pool fee (every trade on the curve) | Set by the option the creator picks, from 0.625% to 3.7879% of the SOL side. Table below. |
| Meteora | 20% of the pool fee, kept by the Meteora program. |
| Platform | About 0.5% of volume. 75% of it buys back and burns $JUSTI, 25% runs the pad. |
| Creator | The rate the creator picked. Paid into the pool on chain; the creator claims it with their own wallet. |
| Holders | 0.5% of volume on holder rewards and split coins, paid in SOL every 10 minutes, pro rata by balance, once a wallet is owed 0.001 SOL. |
| Sniper window | First 5 seconds: the fee starts at 50% and steps down each second. The part above the normal fee: 50% buys back and burns that coin, 30% burns $JUSTI, 20% to the platform. |
| Launch | No launch fee. The creator pays account rent, the network fee and a 0.0002 SOL Jito tip. A dev buy pays the normal fee. |
| Graduation | At 85 SOL in the curve the coin moves to Meteora DAMM v2. 100% of LP is locked forever. The locked LP is split 50% platform and 50% creator, and it earns the pool's trading fees. |
| API | Using the API or SDK adds no fee. Swaps and launches built through the API pay the same fees as the site. |
Every fee option
| Option | tier key | Total | Creator | Holders | Platform | Meteora |
|---|---|---|---|---|---|---|
| Creator 0.00% | creator-0 | 0.625% | 0% | 0% | 0.5% | 0.125% |
| Creator 0.25% | creator-25 | 0.947% | 0.25% | 0% | 0.5076% | 0.1894% |
| Creator 0.50% | creator-50 | 1.25% | 0.5% | 0% | 0.5% | 0.25% |
| Creator 0.75% | creator-75 | 1.5625% | 0.75% | 0% | 0.5% | 0.3125% |
| Creator 1.00% | creator-100 | 1.8939% | 1% | 0% | 0.5152% | 0.3788% |
| Creator 1.25% | creator-125 | 2.2007% | 1.25% | 0% | 0.5106% | 0.4401% |
| Creator 1.50% | creator-150 | 2.5% | 1.5% | 0% | 0.5% | 0.5% |
| Creator 1.75% | creator-175 | 2.8409% | 1.75% | 0% | 0.5227% | 0.5682% |
| Creator 2.00% | creator-200 | 3.125% | 2% | 0% | 0.5% | 0.625% |
| Creator 2.25% | creator-225 | 3.4722% | 2.25% | 0% | 0.5278% | 0.6944% |
| Creator 2.50% | creator-250 | 3.7651% | 2.5% | 0% | 0.512% | 0.753% |
| Holder rewards | holders | 1.25% | 0% | 0.5% | 0.5% | 0.25% |
| Split, creator 0.25% | split-25 | 1.5625% | 0.25% | 0.5% | 0.5% | 0.3125% |
| Split, creator 0.50% | split-50 | 1.8939% | 0.5% | 0.5% | 0.5152% | 0.3788% |
| Split, creator 0.75% | split-75 | 2.2321% | 0.75% | 0.5% | 0.5357% | 0.4464% |
| Split, creator 1.00% | split-100 | 2.5% | 1% | 0.5% | 0.5% | 0.5% |
| Split, creator 1.25% | split-125 | 2.8409% | 1.25% | 0.5% | 0.5227% | 0.5682% |
| Split, creator 1.50% | split-150 | 3.125% | 1.5% | 0.5% | 0.5% | 0.625% |
| Split, creator 1.75% | split-175 | 3.4722% | 1.75% | 0.5% | 0.5278% | 0.6944% |
| Split, creator 2.00% | split-200 | 3.7879% | 2% | 0.5% | 0.5303% | 0.7576% |
Sniper window schedule
The fee in each second after the pool opens. Every option follows the same steps down to its own normal fee.
| Second after launch | Fee (holder rewards option) |
|---|---|
| 0 | 50% |
| 1 | 40.25% |
| 2 | 30.5% |
| 3 | 20.75% |
| 4 | 11% |
| 5+ | 1.25% |
API, SDK, MCP
REST APIBase URL https://server-production-cc13.up.railway.app. JSON, CORS open on every public route.TypeScript SDK@justifun/sdk: launch, quote, buy, sell, subscribe, verifyWebhook. Zero dependencies.MCP server@justifun/mcp: Claude, Cursor and other agents can read coins, quote and build transactions.WebhooksSigned with HMAC-SHA256, retried for about 9 hours.StreamsWebSocket channels per coin, and Server-Sent Events.ProtocolProgram, configs and fee claimer for terminals that tag justi coins.
curl "https://server-production-cc13.up.railway.app/v1/tokens?sort=volume24h&limit=5"
curl "https://server-production-cc13.up.railway.app/v1/pad"All endpoints
41 public endpoints. Each one is documented on its page with parameters, response fields, samples and a Try panel.
ProtocolGET/v1/protocolWhat a terminal needs to tag justi.fun coinsGET/v1/padPad config, fee tiers, fee splits and the sniper window scheduleGET/v1/statusService status: switches and live ingestGET/v1/openapi.jsonThis OpenAPI 3.1 document
TokensGET/v1/tokensCoins, with filters, sort, search and paginationGET/v1/tokenlistEvery coin in one list (for terminals)GET/v1/tokens/{mint}Coin detail: metadata, safety facts, curve, graduation, sniper window, totalsGET/v1/tokens/{mint}/metadataMetaplex metadata JSON for a coinGET/v1/tokens/{mint}/tradesTrades, newest first, cursor paginated (curve and DAMM v2)GET/v1/tokens/{mint}/candlesOHLCV candles from indexed tradesGET/v1/tokens/{mint}/holdersHolders from the latest snapshot (every 10 minutes)GET/v1/tokens/{mint}/burnsBuybacks and burns of one coin, with signatures
PlatformGET/v1/buybacksAll buybacks and burns ($JUSTI and sniper-window coin burns)GET/v1/platform/statsPlatform totalsGET/v1/mint-poolVanity (...JUST) mint pool status
RewardsGET/v1/tokens/{mint}/rewardsHolder reward rounds of one coinGET/v1/wallets/{address}/rewardsWhat a wallet earned from holding, and its payouts with signaturesGET/v1/payoutsConfirmed holder payouts, newest firstGET/v1/creators/{wallet}Creator stats: coins, fees earned and claimable (read live from the pools)
AssetsGET/v1/meta/{id}Metadata JSON by launch id (the uri stored on chain)GET/v1/image/{id}Coin image by launch idGET/v1/banner/{key}3:1 banner by coin mint (or by launch id before it goes live)
TradingGET/v1/quoteQuote a buy or sell (exact in) on the curve or the DAMM v2 poolPOST/v1/swapBuild an unsigned v0 swap transaction for a walletPOST/v1/submitRelay a signed swap built by POST /v1/swapGET/v1/swaps/{id}Status of a swap built through the APIGET/v1/tx/{signature}Status of any transaction signature (and the swap or launch it belongs to)
LaunchesPOST/v1/launchesBuild a launch exactly like the site doesPOST/v1/launches/{id}/submitSend a signed launch (Jito, private)GET/v1/launches/{id}Launch status
WebhooksPOST/v1/webhooksRegister a webhook (the secret is shown once)GET/v1/webhooksWebhooks of this API keyGET/v1/webhooks/{id}One webhookPATCH/v1/webhooks/{id}Change a webhook; enabled=true re-enables one that was disabledDELETE/v1/webhooks/{id}Delete a webhook and its delivery logGET/v1/webhooks/{id}/deliveriesDelivery log, newest firstPOST/v1/webhooks/{id}/testSend one signed webhook.test delivery now
KeysPOST/v1/keysSelf-serve: a wallet signs a message and gets a free-tier keyGET/v1/keys/meThe calling key, its tier and limitsDELETE/v1/keys/meRevoke the calling key (its webhooks stop)
Amounts
Lamports for SOL, raw units for tokens (6 decimals, supply 1,000,000,000). Values that can pass 2^53 are decimal strings. Times are unix seconds. 1 SOL = 1,000,000,000 lamports.