#32 AI Agent
Simmer.Markets
API-first prediction-market interface for AI agents — autonomous trading on Polymarket, Kalshi, and Simmer LMSR via installable skills, with paper trading in virtual $SIM tokens.
$ 7.75M 1m volume
Quick facts
- Team
- 10-50
- Funding
- Backed by The Spartan Group
- The Spartan Group
- Pricing
- Freemium + x402 micropayments · Free tier
- Chains
- Polygon · Base (for x402 payments)
- Venues
- Polymarket · Kalshi · Simmer LMSR sandbox
Stats across DAY · WEEK · MONTH · ALL
From the Polymarket public data API. Updated daily.
Today · 24h
#72
$1.7k
16 active users
This week · 7d
#63
$15.0k
30 active users
This month · 30d
#66
$237.0k
105 active users
All-time · all
#32
$7.75M
1,377 active users
builderCode
The 32-byte hash Polymarket uses to attribute volume to this builder on-chain.
0xed9222e433d100f617b2d2b125fd36f055ee6ebf792e44d2c522ed33e55697f8 What is Simmer.Markets?
Simmer.Markets is an API-first prediction-market platform built by Spartan Labs (the venture studio arm of The Spartan Group, a Singapore-based Web3 fund with $100M deployed capital). Simmer lets autonomous AI agents discover, simulate, and execute trades across three venues — Polymarket USDC, Kalshi USD, and Simmer's own LMSR sandbox in virtual $SIM tokens — through a single unified API. Agents get self-custody wallets with local signing, configurable safety rails (defaults: $100/trade, $500/day, 50 trades/day, kill switch), and installable trading skills covering Kalshi↔Polymarket arbitrage, ESPN price-lag exploits, crypto 5-minute fast markets, F1 constructor signals, Fed dot-plot rate trades, and CPI bin trades. On the Polymarket Builder leaderboard, Simmer ranks #66 by 30-day volume ($237.0k routed) and #32 all-time at $7.75M cumulative, with 105 monthly and 1,377 lifetime active users. Pricing is freemium: free tier (60 calls/min, 1,000 trades/day), Pro tier (3x multiplier), plus pay-per-call x402 micropayments in USDC on Base.
Simmer.Markets is an API-first prediction-market platform purpose-built for autonomous AI agents. Its self-description: 'The prediction market interface built for AI agents. Trade on Polymarket and Kalshi through one API.' The product lets agents discover markets, simulate trades in virtual $SIM tokens, then execute real positions across three venues — Polymarket (USDC.e on Polygon), Kalshi (USD), and Simmer's own LMSR sandbox — without the operator having to wire up multiple SDKs.
On the Polymarket Builder leaderboard, Simmer's builderCode sits at #66 by 30-day volume ($237.0k routed) and #32 all-time ($7.75M cumulative), with 105 monthly active users and 1,377 lifetime. The 13x ratio between lifetime users and current monthly actives suggests a long tail of one-shot agent experiments rather than concentrated whale flow, which is consistent with the product's positioning as a developer playground.
Simmer is built and operated by SpartanLabsXyz, the venture-studio arm of The Spartan Group — a Singapore-based Web3 fund with $100M deployed capital and headquarters in Singapore (with team members in Shanghai, Hong Kong, Dallas, Amsterdam, and London). Spartan Labs lists Simmer alongside three other shipped products: DD Arena (AI evaluation API), Supafund (AI grants directory), and Oncore (in development). The Simmer SDK is open-source on GitHub (github.com/SpartanLabsXyz/simmer-sdk, MIT license, 45 stars).
The product's distinctive technical surface includes self-custody wallets with local key signing, configurable safety rails (per-trade caps, daily limits, stop-loss/take-profit, kill switch), and an installable skills ecosystem hosted at clawhub.ai. Pre-built skills cover cross-platform Kalshi↔Polymarket arbitrage, ESPN-vs-Polymarket sports price-lag exploits, 1-minute candle + Binance volume signals on Polymarket 5-minute crypto fast markets, F1 Drivers Championship constructor signals on Kalshi, Fed FOMC dot-plot rate trades, and CPI bin trading. Agents start with 10,000 $SIM for paper trading and can be claimed by a human via a claim_url to unlock real-asset trading.
Pricing is freemium: free tier offers 60 API calls/minute, 10 daily market imports, 1 agent per account, and 1,000 trades/day. Pro tier is a 3x multiplier (180/min, 50 imports, 10 agents, 5,000 trades/day, no paper-trading cooldown). Beyond Pro, users can burst rate limits via x402 micropayments in USDC on Base at roughly $0.005/call. Simmer itself charges zero spread, commission, or markup.
Verification: confirmed via docs.simmer.markets, simmer.markets/faq.md, the SpartanLabsXyz GitHub org, and Spartan Labs' studio site (spartanlabs.studio) which explicitly lists Simmer as a live product.
Key features
- Single unified API across Polymarket, Kalshi, and Simmer LMSR
- Self-custody wallets with local signing for agents
- Configurable safety rails ($100/trade, $500/day, 50 trades/day defaults + kill switch)
- Paper trading in virtual $SIM with 10,000-unit starting balance
- Pre-built skills: Kalshi↔Polymarket arbitrage, ESPN price-lag, F1 constructors, Fed dot-plot, CPI bins
- x402 USDC-on-Base micropayments for rate-limit bursting
- MIT-licensed open-source SDK on GitHub
Founders & team
- Spartan Labs teamProduct team (venture studio of The Spartan Group)
Spartan Labs is the $100M venture-studio arm of The Spartan Group, a Singapore-based Web3 fund. Simmer is one of four shipped products alongside DD Arena, Supafund, and Oncore.
Funding & investors
- Stage
- Backed by The Spartan Group
- Investors
- The Spartan Group
- Announcement
- https://www.spartanlabs.studio/projects/simmer
What others have written about Simmer.Markets
- Introducing Spartan Labs: A $100M Venture-Building Studio Designed For Web3 — The Spartan Group (Medium)
- Simmer: Prediction Market Trading | openclaw/skills — DeepWiki
- simmer-sdk on PyPI — PyPI
Rank + volume over time
Daily snapshots from our scraper. Charts populate as history accumulates.
All-time rank
Lower is better. Inverted Y-axis.
All-time volume
Cumulative routed volume in USD.
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How to verify Simmer.Markets
- On-chain attribution — every Polymarket Builder routes via an order that includes their
builderCode. The hash above is checkable on Polygon against Polymarket's CTF Exchange. - Polymarket's own verification — $Simmer.Markets carries the official ✓ verified flag in the data API.
- Cross-check Polybot Arena — polybot.arena tracks wallet-level P&L for builder-tagged bots. If a builder claims specific performance, their wallet should be findable there.
- Tier-2 patterns to avoid — we flag builders that match the Tier-2 pattern (no public team, no verifiable claims, recurs across affiliate-SEO listicles). See our /methodology page for the full criteria.
About Simmer.Markets 08 answers
FAQ
01 What is Simmer.Markets?
Simmer.Markets is an API-first prediction-market platform built by Spartan Labs (the venture studio arm of The Spartan Group, a Singapore-based Web3 fund with $100M deployed capital). Simmer lets autonomous AI agents discover, simulate, and execute trades across three venues — Polymarket USDC, Kalshi USD, and Simmer's own LMSR sandbox in virtual $SIM tokens — through a single unified API. Agents get self-custody wallets with local signing, configurable safety rails (defaults: $100/trade, $500/day, 50 trades/day, kill switch), and installable trading skills covering Kalshi↔Polymarket arbitrage, ESPN price-lag exploits, crypto 5-minute fast markets, F1 constructor signals, Fed dot-plot rate trades, and CPI bin trades. On the Polymarket Builder leaderboard, Simmer ranks #66 by 30-day volume ($237.0k routed) and #32 all-time at $7.75M cumulative, with 105 monthly and 1,377 lifetime active users. Pricing is freemium: free tier (60 calls/min, 1,000 trades/day), Pro tier (3x multiplier), plus pay-per-call x402 micropayments in USDC on Base.
02 What is the official website of Simmer.Markets?
Simmer.Markets's official site is https://www.simmer.markets/. We verified the URL by visiting the homepage and confirming it references Polymarket or prediction markets directly. If you believe this URL is incorrect, email [email protected].
03 Is Simmer.Markets verified by Polymarket?
Yes — Simmer.Markets carries Polymarket's official ✓ verified flag (returned by their data API as `verified: true`). This indicates Polymarket has reviewed the builder; it's not a guarantee of product quality or financial outcomes.
04 Who founded Simmer.Markets?
Spartan Labs team (Product team (venture studio of The Spartan Group)). Sourced from the project's own materials and public profiles; we don't fabricate team identities and clearly mark builders whose team is publicly anonymous.
05 Has Simmer.Markets raised funding?
Backed by The Spartan Group; investors include The Spartan Group. Announcement: https://www.spartanlabs.studio/projects/simmer.
06 How much does Simmer.Markets cost?
pricing model: Freemium + x402 micropayments; free tier available; Free: 60 calls/min, 1,000 trades/day, 1 agent. Pro: 3x multiplier. Burst via x402 USDC on Base (~$0.005/call). Simmer charges zero spread/commission.. Sourced from the official site at the time of research; verify the current pricing on the builder's website before subscribing.
07 What are Simmer.Markets's key features?
Single unified API across Polymarket, Kalshi, and Simmer LMSR; Self-custody wallets with local signing for agents; Configurable safety rails ($100/trade, $500/day, 50 trades/day defaults + kill switch); Paper trading in virtual $SIM with 10,000-unit starting balance; Pre-built skills: Kalshi↔Polymarket arbitrage, ESPN price-lag, F1 constructors, Fed dot-plot, CPI bins; x402 USDC-on-Base micropayments for rate-limit bursting; MIT-licensed open-source SDK on GitHub. Sourced from the official site/homepage at the time of research.
08 How does Simmer.Markets compare to similar builders?
Simmer.Markets is ranked #32 all-time, with similar-category peers including UnifAI Network, Ask Gina, EVplusAI. The leaderboard reorders daily — see the history chart for Simmer.Markets's rank trajectory.