manifold

Manifold API

Manifold is a prediction market platform where users create and trade on questions about real-world events. It uses a combination of play-money (mana) and prize-cash, with automated market makers (CPMM) and a rich API for programmatic access.

Check this skill and the official documentation FREQUENTLY for updates. The API is still in alpha and may change without notice.

Community: Join the Manifold Discord for questions, bug reports, and to share what you build.

Source code: Manifold is open source. Type definitions live at common/src/api/schema.ts.

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Key Concepts (Glossary)

Term	Definition
Market (Contract)	A single tradeable question. Called "contract" in the codebase, "market" in the API. Has an outcome type (BINARY, MULTIPLE_CHOICE, PSEUDO_NUMERIC, BOUNTIED_QUESTION, POLL).
Mana (M$)	Play-money currency used for most markets. Cannot be withdrawn for real money.
Prize Cash (CASH)	Real-money currency available on select markets. Can be withdrawn. Identified by token: "CASH" on a market.
Sibling Contract	The mana or prize-cash counterpart of a market. Toggle between them via siblingContractId.
Topic (Group)	A tag applied to markets for categorization. Called "group" in the codebase and API.
CPMM	Constant Product Market Maker. The automated market maker used for binary (cpmm-1) and multi-answer (cpmm-multi-1) markets.
DPM	Dynamic Parimutuel Market — a legacy mechanism (dpm-2) used for older free-response markets.
Probability	A number between 0 and 1 representing the market's current implied probability of YES.
Pool	The liquidity pool of shares backing the market maker. For CPMM markets, shows YES and NO share counts.
Liquidity	Mana deposited into the AMM pool. More liquidity means less price impact per trade.
Bet	A trade on a market. Can be a market order or a limit order (when limitProb is specified).
Limit Order	A bet that only executes at a specified probability price or better. Remains open until filled, cancelled, or expired.
Shares	Units of a position. Winning YES shares pay out M$1 each; losing shares pay M$0.
Resolution	The final outcome of a market: YES, NO, MKT (probability), or CANCEL.
Answer	A possible outcome in a MULTIPLE_CHOICE or FREE_RESPONSE market. Each answer has its own probability.
Bounty	A BOUNTIED_QUESTION market where the creator distributes mana rewards to the best comments/answers.
Poll	A non-trading market type where users simply vote on options.

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Base URLs

Environment	REST API	WebSocket
Production	https://api.manifold.markets	wss://api.manifold.markets/ws
Dev	https://api.dev.manifold.markets	wss://api.dev.manifold.markets/ws

Important: The API was recently moved from https://manifold.markets/api to https://api.manifold.markets. The old domain will be removed in the future. Always use the new domain.

All REST endpoints are prefixed with /v0/.

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Documentation & References

Resource	URL
API Documentation	https://docs.manifold.markets/api
Platform	https://manifold.markets
Source Code (GitHub)	https://github.com/manifoldmarkets/manifold
API Type Definitions	https://github.com/manifoldmarkets/manifold/tree/main/common/src/api/schema.ts
Discord Community	https://discord.com/invite/eHQBNBqXuh
Terms of Service	https://docs.manifold.markets/terms
Data Downloads & Licensing	https://docs.manifold.markets/data

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Authentication

Some endpoints are public (no auth required). Write endpoints and user-specific reads require authentication via an API key.

Generating an API Key

1. Log in to Manifold.
2. Go to your user profile and click "edit".
3. Scroll to the API key field at the bottom.
4. Click the "refresh" button to generate a new key.
5. Copy and store the key securely. Clicking refresh again will invalidate the old key and generate a new one.

Using the API Key

Include the key in the Authorization header:

Authorization: Key {your_api_key}

Alternatively, the API accepts Firebase JWTs via Authorization: Bearer {jwt}, but this is intended for the web client and not recommended for third-party use.

Example Authenticated Request

curl "https://api.manifold.markets/v0/me" \
  -H "Authorization: Key YOUR_API_KEY"

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Rate Limits

There is a rate limit of 500 requests per minute per IP address. Do not use multiple IP addresses to circumvent this limit.

Implement exponential backoff on HTTP 429 responses.

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Fees

• Comments placed through the API incur a M$1 transaction fee.
• Market creation costs mana (see the market creation endpoint for current costs per type).

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Licensing

• Permitted: Bots, automated trading, algorithmic tools, integrations.
• Prohibited: Scraping through means other than the API; circumventing rate limits.
• AI training data: Not permitted for commercial use without a data license. Academic and personal/non-commercial use is allowed. Contact [email protected] for commercial licensing.

---

REST API Endpoints Overview

All endpoints are relative to https://api.manifold.markets/v0.

Users

Endpoint	Method	Auth	Description
/user/[username]	GET	No	Get a user by username. Returns User.
/user/[username]/lite	GET	No	Get basic display info by username. Returns DisplayUser.
/user/by-id/[id]	GET	No	Get a user by unique ID. Returns User.
/user/by-id/[id]/lite	GET	No	Get display info by ID. Returns DisplayUser.
/me	GET	Yes	Get the authenticated user. Returns User.
/users	GET	No	List all users, ordered by creation date desc. Params: limit (max 1000, default 500), before (user ID for pagination).

User Type

User {
  id: string
  createdTime: number
  name: string              // display name
  username: string           // used in URLs
  url: string
  avatarUrl?: string
  bio?: string
  bannerUrl?: string
  website?: string
  twitterHandle?: string
  discordHandle?: string
  isBot?: boolean
  isAdmin?: boolean
  isTrustworthy?: boolean    // moderator
  isBannedFromPosting?: boolean
  userDeleted?: boolean
  balance: number
  totalDeposits: number
  lastBetTime?: number
  currentBettingStreak?: number
}

DisplayUser Type

DisplayUser {
  id: string
  name: string
  username: string
  avatarUrl?: string
}

Portfolio

Endpoint	Method	Auth	Description
/get-user-portfolio	GET	No	Get a user's live portfolio metrics. Param: userId.
/get-user-portfolio-history	GET	No	Get portfolio history over a period. Params: userId, period (daily, weekly, monthly, allTime).
/get-user-contract-metrics-with-contracts	GET	No*	Get a user's positions and their contracts. Params: userId (required), limit (required), offset, order (lastBetTime or profit), perAnswer. *When authenticated, may include private market metrics visible to you.

PortfolioMetrics Type

PortfolioMetrics {
  investmentValue: number
  cashInvestmentValue: number
  balance: number
  cashBalance: number
  spiceBalance: number
  totalDeposits: number
  totalCashDeposits: number
  loanTotal: number
  timestamp: number
  profit?: number
  userId: string
}

LivePortfolioMetrics = PortfolioMetrics & {
  dailyProfit: number
}

Markets — Discovery & Listing

Endpoint	Method	Auth	Description
/markets	GET	No	List markets by creation date desc. Params: limit (max 1000, default 500), sort (created-time, updated-time, last-bet-time, last-comment-time), order (asc/desc), before (market ID for cursor pagination), userId, groupId. Returns LiteMarket[].
/market/[marketId]	GET	No	Get a single market by ID. Returns FullMarket (includes answers, but not bets/comments).
/slug/[marketSlug]	GET	No	Get a market by slug (URL path after username). Returns FullMarket.
/search-markets	GET	No	Search/filter markets (similar to browse page). Returns LiteMarket[]. See parameters below.

Search Markets Parameters

Parameter	Description
term	Search query string. Can be empty.
sort	most-popular (default), newest, score, daily-score, freshness-score, 24-hour-vol, liquidity, subsidy, last-updated, close-date, start-time, resolve-date, random, bounty-amount, prob-descending, prob-ascending.
filter	all (default), open, closed, resolved, news, closing-90-days, closing-week, closing-month, closing-day.
contractType	ALL (default), BINARY, MULTIPLE_CHOICE, DEPENDENT_MULTIPLE_CHOICE, INDEPENDENT_MULTIPLE_CHOICE, BOUNTY, POLL.
topicSlug	Only markets tagged with this topic slug.
creatorId	Only markets by this creator.
limit	0–1000 (default 100).
offset	Number to skip (max 1000 when sort=newest).
beforeTime	Millisecond timestamp cursor for efficient pagination with sort=newest. Pass createdTime of last result.
liquidity	Minimum liquidity per contract/answer.

Markets — Probabilities

Endpoint	Method	Auth	Description
/market/[marketId]/prob	GET	No	Get current probability (max 1s cache). Returns { prob } for binary or { answerProbs: { answerId: prob } } for multi.
/market-probs	GET	No	Batch probabilities for multiple markets (max 1s cache). Param: ids (array, up to 100). Returns `{ marketId: { prob }

Markets — Positions

Endpoint	Method	Auth	Description
/market/[marketId]/positions	GET	No	Get position data for a market. Params: order (shares/profit, default profit), top, bottom, userId, answerId. Returns ContractMetric[].

ContractMetric Type

ContractMetric {
  contractId: string
  from: {
    [period: string]: {     // day, week, month
      profit: number
      profitPercent: number
      invested: number
      prevValue: number
      value: number
    }
  } | undefined
  hasNoShares: boolean
  hasShares: boolean
  hasYesShares: boolean
  invested: number
  loan: number
  maxSharesOutcome: string | null
  payout: number
  profit: number
  profitPercent: number
  totalShares: { [outcome: string]: number }
  userId: string
  userUsername: string
  userName: string
  userAvatarUrl: string
  lastBetTime: number
}

Markets — Creation & Management

Endpoint	Method	Auth	Description
/market	POST	Yes	Create a new market. Returns LiteMarket. See parameters below.
/market/[marketId]/answer	POST	Yes	Add an answer to a MULTIPLE_CHOICE market. Param: text.
/market/[marketId]/add-liquidity	POST	Yes	Add mana to liquidity pool (does not boost). Param: amount.
/market/[marketId]/add-bounty	POST	Yes	Add mana to a bounty question's reward. Param: amount.
/market/[marketId]/award-bounty	POST	Yes	Distribute bounty reward. Params: amount, commentId.
/market/[marketId]/close	POST	Yes	Set close time. Param: closeTime (ms since epoch; omit to close immediately).
/market/[marketId]/group	POST	Yes	Add/remove a topic tag. Params: groupId, remove (optional, true to untag).
/market/[marketId]/resolve	POST	Yes	Resolve a market. See resolution format below.

Market Creation Parameters

Common parameters (all market types):

Parameter	Required	Description
outcomeType	Yes	BINARY, MULTIPLE_CHOICE, PSEUDO_NUMERIC, POLL, BOUNTIED_QUESTION.
question	Yes	The headline question.
description	No	Plain text description. Or use descriptionHtml, descriptionMarkdown, or descriptionJson (stringified TipTap JSON).
closeTime	No	When the market closes (ms since epoch). Defaults to 7 days from now.
visibility	No	public (default) or unlisted.
groupIds	No	Array of topic IDs to tag.
extraLiquidity	No	Additional liquidity to add.

Additional parameters by type:

Type	Extra Parameters
BINARY	initialProb (1–99, required)
PSEUDO_NUMERIC	min, max, isLogScale, initialValue (all required)
MULTIPLE_CHOICE	answers (string[], required), addAnswersMode (DISABLED/ONLY_CREATOR/ANYONE, default DISABLED), shouldAnswersSumToOne (boolean)
BOUNTIED_QUESTION	totalBounty (required)
POLL	answers (string[], required)

Creation costs:

Type	Cost
BINARY	M$50
PSEUDO_NUMERIC	M$250
MULTIPLE_CHOICE	M$25/answer or M$25 for no preset answers

Resolution Formats

Binary markets:

• outcome: YES, NO, MKT, or CANCEL.
• probabilityInt: Optional, used when resolving to MKT.

Multiple Choice (shouldAnswersSumToOne = true):

{
  "outcome": "MKT",
  "resolutions": [
    { "answer": <index>, "pct": <weight> }
  ]
}

Weights must sum to 100. Or use outcome as a number for a single answer index, or CANCEL.

Multiple Choice (shouldAnswersSumToOne = false): Resolve each answer independently with separate requests:

{
  "outcome": "YES",    // or "NO"
  "answerId": "<answer_id>"
}

Numeric markets:

• outcome: CANCEL or a numeric bucket ID.
• value: The resolution value.
• probabilityInt: Required if value is provided.

Trading

Endpoint	Method	Auth	Description
/bet	POST	Yes	Place a bet or limit order. Returns Bet.
/multi-bet	POST	Yes	Place multiple YES bets on a sums-to-one multi-choice market, targeting equal shares per answer. Returns Bet[].
/bet/cancel/[id]	POST	Yes	Cancel an open limit order.
/market/[marketId]/sell	POST	Yes	Sell shares. Params: outcome (YES/NO, defaults to kind held), shares (optional, defaults to all), answerId (required for multi-choice).

Bet Parameters

Parameter	Required	Description
amount	Yes	Amount in mana to bet, before fees.
contractId	Yes	The market ID.
outcome	No	YES (default) or NO.
limitProb	No	Makes this a limit order. A number from 0.01 to 0.99 (whole percentage points only, e.g., 0.01 = 1%).
expiresAt	No	Timestamp (ms) when the limit order auto-cancels.
expiresMillisAfter	No	Milliseconds after creation for auto-cancel.
dryRun	No	If true, simulates without placing.

Multi-Bet Parameters

Parameter	Required	Description
contractId	Yes	Market ID. Must be cpmm-multi-1 with shouldAnswersSumToOne=true.
answerIds	Yes	Array of answer IDs (min 2).
amount	Yes	Total mana to spend across selected answers.
limitProb	No	Per-leg limit price (0.01–0.99, two decimal places).
expiresAt	No	Timestamp (ms) for auto-cancel of unfilled portions.

Comments

Endpoint	Method	Auth	Description
/comment	POST	Yes	Create a top-level comment on a market. Params: contractId, plus one of content (TipTap JSON), html, or markdown. Fee: M$1.
/comments	GET	No	List comments for a market or user. Params: contractId, contractSlug, limit (max 1000), page, userId, order (likes/newest/oldest).

Bets

Endpoint	Method	Auth	Description
/bets	GET	No	List bets. Params: userId, username, contractId (can be multiple), contractSlug, limit (max 1000), before/after (bet ID cursors), beforeTime/afterTime (timestamps), kinds (open-limit), order (asc/desc).

Bet Type

Bet {
  id: string
  contractId: string
  userId: string
  amount: number            // mana spent (filled portion for limits)
  orderAmount: number       // original order amount
  shares: number
  outcome: "YES" | "NO"
  probBefore: number
  probAfter: number
  createdTime: number
  fees: {
    creatorFee: number
    platformFee: number
    liquidityFee: number
  }
  isFilled: boolean
  isCancelled: boolean
  loanAmount: number
  limitProb?: number        // present for limit orders
  fills: Fill[]
  answerId?: string         // for multi-choice markets
}

Fill {
  matchedBetId: string | null
  amount: number
  shares: number
  timestamp: number
  fees: { creatorFee: number; platformFee: number; liquidityFee: number }
}

Topics (Groups)

Endpoint	Method	Auth	Description
/groups	GET	No	List public topics, 500 at a time, newest first. Params: beforeTime, availableToUserId.
/group/[slug]	GET	No	Get a topic by slug.
/group/by-id/[id]	GET	No	Get a topic by ID.

Mana Transfers

Endpoint	Method	Auth	Description
/managram	POST	Yes	Send mana to other users. Params: toIds (array of user IDs), amount (>= 10, sent to each), message (optional).

Transactions

Endpoint	Method	Auth	Description
/txns	GET	No	List transactions, newest first. Params: token (CASH/MANA), offset, limit (max 100), before/after (timestamps), toId, fromId, category.

Leagues

Endpoint	Method	Auth	Description
/leagues	GET	No	Get league standings. Params: userId, season (number), cohort (string).

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Market Types

outcomeType	mechanism	Description
BINARY	cpmm-1	Yes/No market with a single probability (0–1). Most common type.
MULTIPLE_CHOICE	cpmm-multi-1	Multiple answers, each with its own probability. Can be dependent (sum to 100%) or independent.
FREE_RESPONSE	dpm-2	Legacy. Anyone can add answers. Uses DPM mechanism.
PSEUDO_NUMERIC	cpmm-1	Maps probability to a numeric range [min, max]. Can be linear or log scale.
BOUNTIED_QUESTION	—	No trading. Creator distributes bounty to best comments.
POLL	—	No trading. Users vote on options.

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LiteMarket Type

LiteMarket {
  id: string
  creatorId: string
  creatorUsername: string
  creatorName: string
  creatorAvatarUrl?: string
  createdTime: number
  closeTime?: number
  question: string
  url: string                      // always points to manifold.markets
  outcomeType: string
  mechanism: string
  probability: number
  pool: { [outcome: string]: number }
  p?: number                       // CPMM probability constant
  totalLiquidity?: number          // CPMM only
  value?: number                   // PSEUDO_NUMERIC only
  min?: number                     // PSEUDO_NUMERIC only
  max?: number                     // PSEUDO_NUMERIC only
  isLogScale?: boolean             // PSEUDO_NUMERIC only
  volume: number
  volume24Hours: number
  isResolved: boolean
  resolutionTime?: number
  resolution?: string
  resolutionProbability?: number   // for MKT resolution
  uniqueBettorCount: number
  lastUpdatedTime?: number
  lastBetTime?: number
  token?: "MANA" | "CASH"
  siblingContractId?: string       // toggle between mana/cash version
}

FullMarket Type

FullMarket = LiteMarket & {
  answers?: Answer[]                          // multi markets only
  shouldAnswersSumToOne?: boolean             // multi markets only
  addAnswersMode?: "ANYONE" | "ONLY_CREATOR" | "DISABLED"
  options?: { text: string; votes: number }[] // poll only
  totalBounty?: number                        // bounty only
  bountyLeft?: number                         // bounty only
  description: JSONContent                    // TipTap rich text
  textDescription: string                     // plain text
  coverImageUrl?: string
  groupSlugs?: string[]                       // topic tags
}

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WebSocket API

Manifold provides a real-time WebSocket server for subscribing to live updates.

Connection

wss://api.manifold.markets/ws         (production)
wss://api.dev.manifold.markets/ws     (dev)

No authentication is required to connect. Authentication is optional (for user-specific topics).

Message Format

All messages are JSON. Client messages must include:

• type: identify, subscribe, unsubscribe, or ping.
• txid: A unique number identifying the message.

The server acknowledges each message:

{ "type": "ack", "txid": 123, "success": true }

Subscribing to Topics

Send a subscribe message:

{
  "type": "subscribe",
  "txid": 1,
  "topics": ["global/new-bet", "contract/[marketId]"]
}

Available Topics

Global Topics

Topic	Description
global/new-bet	All new bets across all markets.
global/new-contract	All new markets being created.
global/new-comment	All new comments across all markets.
global/new-subsidy	All new liquidity subsidies.
global/updated-contract	Updates to any public market.

Per-Market Topics (replace [marketId] with actual ID)

Topic	Description
contract/[marketId]	General market updates.
contract/[marketId]/new-bet	New bets on this market.
contract/[marketId]/new-comment	New comments on this market.
contract/[marketId]/new-subsidy	New liquidity subsidies.
contract/[marketId]/new-answer	New answers added (multi-choice).
contract/[marketId]/updated-answers	Updates to existing answers.
contract/[marketId]/orders	Limit order updates.
contract/[marketId]/chart-annotation	Chart annotations.
contract/[marketId]/user-metrics/[userId]	User position updates in this market.

Other Topics

Topic	Description
user/[userId]	Updates to a user's public info.
answer/[answerId]/update	Updates to a specific answer.
tv_schedule	Updates to the TV schedule.

Keep-Alive

Send periodic pings (every 30–60 seconds) to keep the connection alive. If no ping is received for 60 seconds, the server terminates the connection.

{ "type": "ping", "txid": 42 }

Broadcast Messages

The server sends updates as broadcast messages:

{
  "type": "broadcast",
  "topic": "global/new-bet",
  "data": { ... }
}

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Common Patterns

List Recent Markets

curl -s "https://api.manifold.markets/v0/markets?limit=5" | jq '.[].question'

Get a Single Market by ID

curl -s "https://api.manifold.markets/v0/market/3zspH9sSzMlbFQLn9GKR" | jq '{question, probability, volume, isResolved}'

Get a Market by Slug

curl -s "https://api.manifold.markets/v0/slug/will-carrick-flynn-win-the-general" | jq '{question, probability}'

Search for Open Binary Markets

curl -s "https://api.manifold.markets/v0/search-markets?term=AI&sort=liquidity&filter=open&contractType=BINARY&limit=10" | jq '.[].question'

Get Current Probability

curl -s "https://api.manifold.markets/v0/market/9t61v9e7x4/prob" | jq '.'

Get Batch Probabilities

curl -s "https://api.manifold.markets/v0/market-probs?ids=9t61v9e7x4&ids=ZNlNdzz690" | jq '.'

Place a YES Bet

curl -X POST "https://api.manifold.markets/v0/bet" \
  -H "Authorization: Key YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"amount": 10, "contractId": "MARKET_ID", "outcome": "YES"}'

Place a Limit Order

curl -X POST "https://api.manifold.markets/v0/bet" \
  -H "Authorization: Key YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "amount": 100,
    "contractId": "MARKET_ID",
    "outcome": "YES",
    "limitProb": 0.40,
    "expiresMillisAfter": 86400000
  }'

Sell All Shares in a Market

curl -X POST "https://api.manifold.markets/v0/market/MARKET_ID/sell" \
  -H "Authorization: Key YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"outcome": "YES"}'

Cancel a Limit Order

curl -X POST "https://api.manifold.markets/v0/bet/cancel/BET_ID" \
  -H "Authorization: Key YOUR_API_KEY"

Create a Binary Market

curl -X POST "https://api.manifold.markets/v0/market" \
  -H "Authorization: Key YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "outcomeType": "BINARY",
    "question": "Will it rain in SF tomorrow?",
    "descriptionMarkdown": "Resolves YES if measurable rainfall is recorded at SFO weather station.",
    "initialProb": 30,
    "closeTime": 1735689600000
  }'

Create a Multiple Choice Market

curl -X POST "https://api.manifold.markets/v0/market" \
  -H "Authorization: Key YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "outcomeType": "MULTIPLE_CHOICE",
    "question": "Who will win the award?",
    "answers": ["Alice", "Bob", "Charlie"],
    "shouldAnswersSumToOne": true,
    "addAnswersMode": "ONLY_CREATOR"
  }'

Resolve a Binary Market

curl -X POST "https://api.manifold.markets/v0/market/MARKET_ID/resolve" \
  -H "Authorization: Key YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"outcome": "YES"}'

Get Your Portfolio

curl -s "https://api.manifold.markets/v0/get-user-portfolio?userId=YOUR_USER_ID" | jq '.'

Get Top Positions on a Market

curl -s "https://api.manifold.markets/v0/market/MARKET_ID/positions?top=5&order=profit" | jq '.[].userName'

Paginate Through All Markets (by newest)

# Page 1
curl -s "https://api.manifold.markets/v0/search-markets?sort=newest&limit=100" > page1.json

# Page 2: use createdTime of last result
BEFORE_TIME=$(jq '.[-1].createdTime' page1.json)
curl -s "https://api.manifold.markets/v0/search-markets?sort=newest&limit=100&beforeTime=$BEFORE_TIME" > page2.json

Paginate Through Bets

# First page
curl -s "https://api.manifold.markets/v0/bets?contractId=MARKET_ID&limit=100" > bets1.json

# Next page: use ID of last bet
BEFORE=$(jq -r '.[-1].id' bets1.json)
curl -s "https://api.manifold.markets/v0/bets?contractId=MARKET_ID&limit=100&before=$BEFORE" > bets2.json

Send Mana to Users

curl -X POST "https://api.manifold.markets/v0/managram" \
  -H "Authorization: Key YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"toIds": ["USER_ID_1", "USER_ID_2"], "amount": 100, "message": "Thanks!"}'

Post a Comment

curl -X POST "https://api.manifold.markets/v0/comment" \
  -H "Authorization: Key YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"contractId": "MARKET_ID", "markdown": "Great question! I think YES is undervalued."}'

WebSocket Subscription (Node.js)

const ws = new WebSocket("wss://api.manifold.markets/ws");
let txid = 0;

ws.onopen = () => {
  ws.send(JSON.stringify({
    type: "subscribe",
    txid: txid++,
    topics: ["global/new-bet"]
  }));
};

ws.onmessage = (event) => {
  const msg = JSON.parse(event.data);
  if (msg.type === "broadcast") {
    console.log("New bet:", msg.data);
  }
};

// Keep-alive ping every 30 seconds
setInterval(() => {
  ws.send(JSON.stringify({ type: "ping", txid: txid++ }));
}, 30000);

---

Usage Tips

• All timestamps are UNIX milliseconds (JavaScript Date.now() style), not seconds.
• Never hardcode API keys — use environment variables or secure key storage.
• Market URLs always point to https://manifold.markets regardless of which API instance you're using. The username in the URL path doesn't need to be correct (e.g., manifold.markets/anyone/market-slug works).
• GET parameters go in the query string. POST/PUT parameters go in the JSON body.
• Limit orders with limitProb crossing the current market price will partially fill immediately. Any unfilled remainder stays as a resting limit order.
• limitProb precision: Only whole percentage points (two decimal places, e.g., 0.01, 0.50, 0.99).
• Multi-choice markets come in two flavors: dependent (shouldAnswersSumToOne=true, probabilities sum to 100%) and independent (each answer is effectively a separate binary market).
• Combine REST + WebSocket for best results: use REST for initial state, WebSocket for real-time deltas.
• Paginate responsibly: For /search-markets with sort=newest, use beforeTime for efficient deep pagination. For /bets and /markets, use cursor-based pagination with before/after.
• Market token type matters: check the token field (MANA or CASH) to know if a market uses play-money or prize-cash.
• Dry run bets by passing dryRun: true to simulate without placing.
• Description formats: You can provide market descriptions as plain text (description), HTML (descriptionHtml), Markdown (descriptionMarkdown), or TipTap JSON (descriptionJson). Only provide one.

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Error Handling

API responses are JSON. Successful requests return HTTP 200 with a JSON result. Error responses (4xx/5xx) return a JSON object with an error message.

Status	Meaning
200	Success
400	Bad request (invalid parameters)
401	Unauthorized (missing or invalid API key)
403	Forbidden (insufficient permissions)
404	Not found
429	Rate limited (500 req/min exceeded)
5xx	Server error

Implement retry with exponential backoff for 429 and 5xx responses.

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Internal API

Manifold has some internal endpoints not part of the official API. These are undocumented and subject to change without notice.

Endpoint	Method	Auth	Description
/unresolve	POST	Yes	Unresolve a market. Param: contractId.

Note: Internal endpoints are not prefixed with /v0.

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Versioning

The current API version is v0 under /v0/. The API is still in alpha. Monitor the official documentation and the Discord for breaking changes.