What is the IBKR TWS API rate limit?

Your market-data lines divided by 2 requests per second. Every account starts with 100 lines, so the default is 50 requests per second; 200 lines give 100 per second. Only the request that starts a data flow counts (IBKR TWS API docs, read 2026-10-11).

What happens if I exceed the TWS API pacing limit?

It depends on the TWS setting 'Reject messages above maximum allowed message rate vs applying pacing'. With reject on, TWS returns error 100 and terminates the API session after three violations. With it off, TWS queues and paces the requests.

How do I poll IBKR option chains without hitting rate limits?

Use reqSecDefOptParams, which returns expiries and strikes without the throttling that applies when reqContractDetails enumerates a chain from an incompletely defined contract.

How many market-data lines does IBKR give?

100 to start, never fewer. After the first month IBKR allocates the greater of monthly commissions divided by 8, equity times 100 divided by $1,000,000, or 100. Lines are shared between TWS and API connections.

IBKR TWS API Rate Limits 2026

Education, not investment advice. Past performance does not predict future results. How we check our numbers.

The IBKR TWS API allows your market-data lines divided by 2 requests per second, which is 50 requests per second on the default 100 lines, and it scales up as lines grow (200 lines give 100 per second). On top of that, historical bars of 30 seconds or less carry their own pacing rules: no identical request within 15 seconds, no 6 or more requests for the same contract, exchange and tick type within 2 seconds, and no more than 60 requests in any 10-minute window. Both rules come from IBKR's current TWS API documentation, read 2026-10-11¹². What happens on a breach depends on a TWS setting: reject with error 100 (three strikes end the session) or queue and pace automatically³. Compare brokers in the Broker API Comparator.

What is the TWS API request limit?

Rule	Value	Source
Requests per second	Market-data lines ÷ 2	IBKR pacing docs¹
Default lines	100, so 50 requests/second	IBKR pacing docs¹
Example with more lines	200 lines, 100 requests/second	IBKR pacing docs¹
FIX through IB Gateway	250 messages/second	IBKR pacing docs¹

Only the request that starts a data flow counts: a market-data subscription is one request, however many ticks it delivers afterwards¹. IBKR notes that above 50 requests per second "some orders may be queued and delayed" and points heavy users to the FIX API¹.

What happens when I exceed it?

TWS and IB Gateway have a Global Configuration setting under API > Settings: "Reject messages above maximum allowed message rate vs applying pacing"³.

Checked (reject): TWS returns error code 100 for each request over the limit. After three violations the API session terminates, which surfaces as WinError 10053 on Windows or a broken pipe on macOS and Linux³.
Unchecked (pace): TWS queues the excess and acknowledges requests in the EReader thread before moving on³.

For an unattended agent, pacing is the safer default, but it turns a burst into latency. A client-side token bucket at your limit keeps both behaviours out of the hot path.

What are the historical-data pacing rules?

IBKR's "Pacing Violations for Small Bars (30 secs or less)" page lists three restrictions²:

Restriction	Threshold
Identical historical requests	Not within 15 seconds
Same contract, exchange and tick type	Fewer than 6 requests within 2 seconds
Requests in any 10-minute period	No more than 60
BID_ASK requests	Count twice

IBKR states that "these limitations apply to all our clients and it is not possible to overcome them", and suggests a specialized data provider if they do not fit your needs². The current docs scope these rules to bars of 30 seconds or less. IBKR's older TWS reference, now marked deprecated, also listed a maximum of 50 simultaneous open historical requests⁴; the current page does not restate that number, so keep concurrency well below it.

How many instruments can I stream at once?

As many as your market-data lines. Every client starts with 100 concurrent lines and never falls below 100⁵. After the first month the allocation is the greater of monthly commissions divided by 8, equity × 100 / $1,000,000 (rounded down), or 100, so an account with $500 of monthly commissions and $1,245,000 of equity gets 124 lines⁵. Lines are shared between TWS watchlists and every API connection under the same username⁶. Because the request limit is lines ÷ 2, buying more lines through commissions or a quote booster also raises your requests per second¹.

How do I pull option chains without hitting limits?

Use reqSecDefOptParams. IBKR's option-chain page says that enumerating chains through reqContractDetails with an incompletely defined contract is throttled and slows as the definition becomes more ambiguous, and that reqSecDefOptParams "was introduced that does not have the throttling limitation"⁷. It returns the expiries and strikes for an underlying; some strike-expiry combinations may not be valid contracts, so validate before subscribing.

How should a compliant client be built?

One token bucket at your lines ÷ 2 per second for every outbound request.
A historical queue with a rolling 10-minute counter (cap 60), a per-contract 2-second debounce, a 15-second identical-request guard, and BID_ASK counted twice.
Pacing mode on in TWS for unattended runs, so a burst queues instead of killing the session.
reqSecDefOptParams for chains, never reqContractDetails in a loop.
Subscription rotation through your line budget, shared with any TWS watchlists.

For the cost side (the API is free; commissions and market-data subscriptions are not), see Interactive Brokers API Pricing 2026.

Verified figures

The lines ÷ 2 rule, the 100-line default, the 200-line example and the FIX 250 messages/second figure, the reject-versus-pace setting and error 100, the small-bar historical pacing rules, the line-allocation formula and the option-chain guidance were read from IBKR's current TWS API and market-data documentation on 2026-10-11.

Connects to

Interactive Brokers API Pricing 2026: the cost side of the same API.
Alpaca vs Interactive Brokers API 2026: pacing versus a flat per-minute cap.
Choosing a Broker API in 2026: the five-broker pillar.
Broker API Comparator: rate models side by side.

References

Interactive Brokers. "TWS API: Pacing Limitations, Introduction" (maximum requests per second = market-data lines / 2; default 100 lines = 50/second; 200 lines = 100/second; FIX via IB Gateway 250 messages/second). Read 2026-10-11. https://www.interactivebrokers.com/docs/tws-api/doc/pacing-limitations/introduction ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸
Interactive Brokers. "TWS API: Pacing Violations for Small Bars (30 secs or less)" (15-second identical-request rule; 6 requests per contract/exchange/tick type in 2 seconds; 60 requests per 10 minutes; BID_ASK counted twice). Read 2026-10-11. https://www.interactivebrokers.com/docs/tws-api/doc/market-data-historical/historical-data-limitations/pacing-violations-for-small-bars-30-secs-or-less ↩ ↩² ↩³
Interactive Brokers. "TWS API: Pacing Behavior" (reject vs pace setting; error 100; session ends after three violations). Read 2026-10-11. https://www.interactivebrokers.com/docs/tws-api/doc/pacing-limitations/pacing-behavior ↩ ↩² ↩³ ↩⁴
Interactive Brokers. "TWS API v9.72+: Historical Data Limitations" (legacy reference, marked deprecated; maximum 50 simultaneous open historical requests). Read 2026-10-11. https://interactivebrokers.github.io/tws-api/historical_limitations.html ↩
Interactive Brokers. "Market Data Lines: How Market Data is Allocated" (100 lines minimum; commissions / 8 or equity × 100 / $1,000,000). Read 2026-10-11. https://www.interactivebrokers.com/docs/general/market-data-subscriptions/market-data-lines/how-market-data-is-allocated ↩ ↩²
Interactive Brokers. "Market Data Lines: Introduction" (lines shared between TWS and API connections). Read 2026-10-11. https://www.interactivebrokers.com/docs/general/market-data-subscriptions/market-data-lines/introduction ↩
Interactive Brokers. "TWS API: Option Chains" (reqContractDetails throttled for chains; reqSecDefOptParams without the throttling limitation). Read 2026-10-11. https://www.interactivebrokers.com/docs/tws-api/doc/contracts-financial-instruments/option-chains/introduction ↩

Verified engine output

Show the recompute-verified inputs and outputs

Multi-asset brokers including futures coverage

Inputs
require_futures	1
max_auth_complexity	5

Result
filters › require options	false
filters › require futures	true
filters › require crypto	false
filters › require mcp	false
filters › require free tier	false
filters › max auth complexity	5
results › row 1 › broker › id	ibkr
results › row 1 › broker › name	Interactive Brokers
results › row 1 › broker › url	https://www.interactivebrokers.com/
results › row 1 › broker › docs url	https://www.interactivebrokers.com/en/trading/ib-api.php
results › row 1 › broker › auth	OAuth + TWS/IB Gateway
results › row 1 › broker › auth complexity	5
results › row 1 › broker › order types (10 items)	[...]
results › row 1 › broker › rate limits	Market-data lines / 2 requests per second (50 on the default 100 lines); small-bar history 60 requests per 10 min
results › row 1 › broker › market data › row 1	Global equities via subscription bundles
results › row 1 › broker › market data › row 2	Level-2 depth on most exchanges
results › row 1 › broker › market data › row 3	Historical depth across asset classes
results › row 1 › broker › mcp	official
results › row 1 › broker › mcp note	Official IBKR Connector: remote MCP at api.ibkr.com, IBKR sign-in, one account; drafts trade instructions that you submit as orders yourself
results › row 1 › broker › assets › stocks	true
results › row 1 › broker › assets › options	true
results › row 1 › broker › assets › futures	true
results › row 1 › broker › assets › crypto	true
results › row 1 › broker › assets › forex	true
results › row 1 › broker › assets › bonds	true
results › row 1 › broker › account minimum	0
results › row 1 › broker › commission	Tiered per-share or fixed; ~$0.0035/sh tiered
results › row 1 › broker › good for	Multi-asset-class, international, scale
results › row 1 › broker › has free tier	false
results › row 1 › broker › notes › row 1	Requires TWS or IB Gateway running locally
results › row 1 › broker › notes › row 2	Idempotency via client-supplied orderId
results › row 1 › broker › notes › row 3	Fully headless gateway is possible but under-documented
results › row 1 › score	2
results › row 1 › max score	2
results › row 1 › fits	true
results › row 2 › broker › id	alpaca
results › row 2 › broker › name	Alpaca
results › row 2 › broker › url	https://alpaca.markets/
results › row 2 › broker › docs url	https://alpaca.markets/docs/
results › row 2 › broker › auth	API Key + Secret
results › row 2 › broker › auth complexity	1
results › row 2 › broker › order types (10 items)	[...]
results › row 2 › broker › rate limits	Trading API 200 req/min; market data 200/min free, 10,000/min on Algo Trader Plus
results › row 2 › broker › market data › row 1	IEX real-time (free)
results › row 2 › broker › market data › row 2	Full SIP on Algo Trader Plus ($99/mo)
results › row 2 › broker › market data › row 3	Historical bars + trades + quotes
results › row 2 › broker › mcp	official
results › row 2 › broker › mcp note	Official open-source MCP server (V2 rewrite on FastMCP/OpenAPI); data, paper and live trading
results › row 2 › broker › assets › stocks	true
results › row 2 › broker › assets › options	true
results › row 2 › broker › assets › futures	false
results › row 2 › broker › assets › crypto	true
results › row 2 › broker › assets › forex	false
results › row 2 › broker › assets › bonds	false
results › row 2 › broker › account minimum	0
results › row 2 › broker › commission	$0 (PFOF on equities)
results › row 2 › broker › good for	Solo AI operator, paper-to-live parity
results › row 2 › broker › has free tier	true
results › row 2 › broker › notes › row 1	Free paper trading with same API surface as live
results › row 2 › broker › notes › row 2	Real-time OPRA options data needs Algo Trader Plus; Basic gets the indicative feed
results › row 2 › broker › notes › row 3	Python/Go SDKs mature; rate-limit backoff documented
results › row 2 › score	1
results › row 2 › max score	2
results › row 2 › fits	false
results › row 2 › fail reasons › row 1	Futures
results › row 3 › broker › id	tradier
results › row 3 › broker › name	Tradier
results › row 3 › broker › url	https://tradier.com/
results › row 3 › broker › docs url	https://developer.tradier.com/
results › row 3 › broker › auth	OAuth 2.0
results › row 3 › broker › auth complexity	3
results › row 3 › broker › order types (8 items)	[...]
results › row 3 › broker › rate limits	120 req/min standard and market data, 60 req/min trading (production)
results › row 3 › broker › market data › row 1	Real-time equities + options (streaming)
results › row 3 › broker › market data › row 2	Historical OHLC back ~5 years
results › row 3 › broker › market data › row 3	No Level-2 depth
results › row 3 › broker › mcp	official
results › row 3 › broker › mcp note	Official hosted MCP server (Streamable HTTP, personal API token); market data, accounts and order placement
results › row 3 › broker › assets › stocks	true
results › row 3 › broker › assets › options	true
results › row 3 › broker › assets › futures	false
results › row 3 › broker › assets › crypto	false
results › row 3 › broker › assets › forex	false
results › row 3 › broker › assets › bonds	false
results › row 3 › broker › account minimum	0
results › row 3 › broker › commission	$0 equities (PFOF), $0.35/contract options Pro
results › row 3 › broker › good for	Options-first retail, multi-leg strategies
results › row 3 › broker › has free tier	true
results › row 3 › broker › notes › row 1	Free sandbox with delayed data
results › row 3 › broker › notes › row 2	Strong options chain + multi-leg order API
results › row 3 › broker › notes › row 3	US-only account eligibility
results › row 3 › score	1
results › row 3 › max score	2
results › row 3 › fits	false
results › row 3 › fail reasons › row 1	Futures
results › row 4 › broker › id	robinhood
results › row 4 › broker › name	Robinhood
results › row 4 › broker › url	https://robinhood.com/
results › row 4 › broker › docs url	https://docs.robinhood.com/
results › row 4 › broker › auth	API key (Crypto Trading API); Robinhood sign-in (Trading MCP)
results › row 4 › broker › auth complexity	3
results › row 4 › broker › order types › row 1	market
results › row 4 › broker › order types › row 2	limit
results › row 4 › broker › order types › row 3	stop
results › row 4 › broker › order types › row 4	stop-limit
results › row 4 › broker › rate limits	Not publicly documented
results › row 4 › broker › market data › row 1	Delayed quotes in public tier
results › row 4 › broker › market data › row 2	Limited historical depth
results › row 4 › broker › market data › row 3	No public Level-2
results › row 4 › broker › mcp	official
results › row 4 › broker › mcp note	Official Robinhood Trading MCP (Agentic Trading): long equities, options and crypto, only in a dedicated agentic account; no multi-leg options
results › row 4 › broker › assets › stocks	true
results › row 4 › broker › assets › options	true
results › row 4 › broker › assets › futures	false
results › row 4 › broker › assets › crypto	true
results › row 4 › broker › assets › forex	false
results › row 4 › broker › assets › bonds	false
results › row 4 › broker › account minimum	0
results › row 4 › broker › commission	$0 (PFOF), $5/mo Gold for margin + extras
results › row 4 › broker › good for	Agent-driven trading from an existing Robinhood account; no REST API for stocks or options
results › row 4 › broker › has free tier	true
results › row 4 › broker › notes › row 1	Official REST API covers crypto only; stocks and options are reachable only through the Trading MCP
results › row 4 › broker › notes › row 2	Trade approvals are off by default for external MCP agents
results › row 4 › broker › notes › row 3	Paper trading unavailable
results › row 4 › score	1
results › row 4 › max score	2
results › row 4 › fits	false
results › row 4 › fail reasons › row 1	Futures
results › row 5 › broker › id	schwab
results › row 5 › broker › name	Schwab
results › row 5 › broker › url	https://www.schwab.com/
results › row 5 › broker › docs url	https://developer.schwab.com/
results › row 5 › broker › auth	OAuth 2.0 (3-legged)
results › row 5 › broker › auth complexity	4
results › row 5 › broker › order types (9 items)	[...]
results › row 5 › broker › rate limits	120 req/min for non-order calls per app; order writes 0-120/min per account, set at app registration
results › row 5 › broker › market data › row 1	Real-time equities + options quotes
results › row 5 › broker › market data › row 2	Historical bars (1m to daily)
results › row 5 › broker › market data › row 3	No exchange depth via API
results › row 5 › broker › mcp	community
results › row 5 › broker › mcp note	No official MCP; community servers wrap the Trader API (self-hosted, re-authorize when the 7-day refresh token expires)
results › row 5 › broker › assets › stocks	true
results › row 5 › broker › assets › options	true
results › row 5 › broker › assets › futures	false
results › row 5 › broker › assets › crypto	false
results › row 5 › broker › assets › forex	false
results › row 5 › broker › assets › bonds	false
results › row 5 › broker › account minimum	0
results › row 5 › broker › commission	$0 equities, $0.65/contract options
results › row 5 › broker › good for	Established retail, post-TDA API migration
results › row 5 › broker › has free tier	true
results › row 5 › broker › notes › row 1	API rebuilt after TD Ameritrade integration; still maturing
results › row 5 › broker › notes › row 2	Orders cover stocks, ETFs and options; futures and forex trade on thinkorswim, not through the API
results › row 5 › broker › notes › row 3	Requires individual developer registration and app review
results › row 5 › broker › notes › row 4	Token refresh flow is finicky vs Alpaca/Tradier
results › row 5 › score	1
results › row 5 › max score	2
results › row 5 › fits	false
results › row 5 › fail reasons › row 1	Futures
fitting brokers › row 1 › broker › id	ibkr
fitting brokers › row 1 › broker › name	Interactive Brokers
fitting brokers › row 1 › broker › url	https://www.interactivebrokers.com/
fitting brokers › row 1 › broker › docs url	https://www.interactivebrokers.com/en/trading/ib-api.php
fitting brokers › row 1 › broker › auth	OAuth + TWS/IB Gateway
fitting brokers › row 1 › broker › auth complexity	5
fitting brokers › row 1 › broker › order types (10 items)	[...]
fitting brokers › row 1 › broker › rate limits	Market-data lines / 2 requests per second (50 on the default 100 lines); small-bar history 60 requests per 10 min
fitting brokers › row 1 › broker › market data › row 1	Global equities via subscription bundles
fitting brokers › row 1 › broker › market data › row 2	Level-2 depth on most exchanges
fitting brokers › row 1 › broker › market data › row 3	Historical depth across asset classes
fitting brokers › row 1 › broker › mcp	official
fitting brokers › row 1 › broker › mcp note	Official IBKR Connector: remote MCP at api.ibkr.com, IBKR sign-in, one account; drafts trade instructions that you submit as orders yourself
fitting brokers › row 1 › broker › assets › stocks	true
fitting brokers › row 1 › broker › assets › options	true
fitting brokers › row 1 › broker › assets › futures	true
fitting brokers › row 1 › broker › assets › crypto	true
fitting brokers › row 1 › broker › assets › forex	true
fitting brokers › row 1 › broker › assets › bonds	true
fitting brokers › row 1 › broker › account minimum	0
fitting brokers › row 1 › broker › commission	Tiered per-share or fixed; ~$0.0035/sh tiered
fitting brokers › row 1 › broker › good for	Multi-asset-class, international, scale
fitting brokers › row 1 › broker › has free tier	false
fitting brokers › row 1 › broker › notes › row 1	Requires TWS or IB Gateway running locally
fitting brokers › row 1 › broker › notes › row 2	Idempotency via client-supplied orderId
fitting brokers › row 1 › broker › notes › row 3	Fully headless gateway is possible but under-documented
fitting brokers › row 1 › score	2
fitting brokers › row 1 › max score	2
fitting brokers › row 1 › fits	true

Computed live at build time.

Frequently asked questions

What is the IBKR TWS API rate limit?: Your market-data lines divided by 2 requests per second. Every account starts with 100 lines, so the default is 50 requests per second; 200 lines give 100 per second. Only the request that starts a data flow counts (IBKR TWS API docs, read 2026-10-11).
What happens if I exceed the TWS API pacing limit?: It depends on the TWS setting 'Reject messages above maximum allowed message rate vs applying pacing'. With reject on, TWS returns error 100 and terminates the API session after three violations. With it off, TWS queues and paces the requests.
What triggers an IBKR historical-data pacing violation?: For bars of 30 seconds or less: an identical request within 15 seconds, 6 or more requests for the same contract, exchange and tick type within 2 seconds, or more than 60 requests in any 10-minute period. BID_ASK requests count twice.
How do I poll IBKR option chains without hitting rate limits?: Use reqSecDefOptParams, which returns expiries and strikes without the throttling that applies when reqContractDetails enumerates a chain from an incompletely defined contract.
How many market-data lines does IBKR give?: 100 to start, never fewer. After the first month IBKR allocates the greater of monthly commissions divided by 8, equity times 100 divided by $1,000,000, or 100. Lines are shared between TWS and API connections.

The 12 vendor figures on this page, each with its source and the date it was checked, are also in the vendor price reference, where every figure has its own link.