What is the latest Interactive Brokers TWS API version in 2026?

TWS API 10.47, released May 20 2026, is the latest channel and the first 2026 line with Python API binaries. The stable channel is 10.45, released Mar 30 2026 (verified 2026-06-16).

What did TWS API 10.47 remove?

It removed the legacy fundamentals path: reqFundamentalData, reqFundamentalsDataProtoBuf, cancelFundamentalData, cancelFundamentalsDataProtoBuf, their callbacks, and the FUNDAMENTAL_RATIOS = 47 tick type. Code calling these stops returning data on a 10.47 client.

What is the $LEDGER- prefix in TWS API 10.47?

A new API setting that prepends $LEDGER- to per-currency account-value keys (e.g. $LEDGER-CashBalance) so they are distinct from account-level keys. It is off by default for upgrading users and on for new users, and it affects reqAccountUpdates and reqAccountUpdatesMulti.

Did the IBKR API rate limits change in the 2026 updates?

No. The 50 messages/second client cap and the historical-data pacing rules (60 per 10 minutes, 6 per 2 seconds for the same contract, no identical request within 15 seconds, BID_ASK counted double, 50 simultaneous open requests) carry over unchanged (verified 2026-06-16).

Interactive Brokers API Updates 2026: TWS 10.47 Changelog

TWS API 10.47, released May 20 2026, breaks two common integrations: it removes reqFundamentalData (plus its protobuf siblings, callbacks, and the FUNDAMENTAL_RATIOS = 47 tick type), and it adds a setting that prepends a $LEDGER- prefix to per-currency account values, changing the keys returned by reqAccountUpdates and reqAccountUpdatesMulti. The stable channel sits one step back at 10.45 (Mar 30 2026); 10.47 is the latest and the first 2026 line with Python API binaries¹². If your bot reads fundamentals or parses per-currency balances, read this before you upgrade. Compare IBKR against other brokers in the Broker API Comparator.

TL;DR

Stable: TWS API 10.45, released Mar 30 2026¹.
Latest: TWS API 10.47, released May 20 2026 — first 2026 line shipping Python API support¹.
10.47 removed fundamentals: reqFundamentalData, reqFundamentalsDataProtoBuf, cancelFundamentalData, cancelFundamentalsDataProtoBuf, their callbacks, and tick type FUNDAMENTAL_RATIOS = 47²³.
10.47 $LEDGER- prefix: a new API setting prepends $LEDGER- to per-currency keys (e.g. $LEDGER-CashBalance); off by default for upgrading users, on for new users; affects reqAccountUpdates / reqAccountUpdatesMulti²⁴.
10.46 added ticks: odd-lot tick types 105–108 and generic tick 787².
Rate limits unchanged: 50 messages/second client cap and the historical-data pacing rules still hold⁵.

Version state in June 2026

IBKR runs two parallel channels on the TWS API download page¹:

Channel	Version	Release date	API languages
Stable	10.45	Mar 30 2026	Java, C++, C#/.NET, ActiveX, DDE
Latest	10.47	May 20 2026	Above plus Python

Verified 2026-06-16¹. The split matters for a production bot: the stable channel is the conservative default, but the Python API binaries ride the latest channel, so a Python integration on the current download is already on 10.47 and inherits its breaking changes. The 2026 production release notes also list 10.46 and 10.48 entries beyond what the download page surfaces as the headline pair².

The removed fundamentals API

The clearest break in 10.47 is the deletion of the legacy fundamentals path. Removed methods: reqFundamentalData, reqFundamentalsDataProtoBuf, cancelFundamentalData, and cancelFundamentalsDataProtoBuf, along with the matching callbacks and the FUNDAMENTAL_RATIOS = 47 tick type²³. Code calling any of these against a 10.47 client stops returning data. This was a financial-statement and ratio feed (Reuters-sourced), separate from corporate-event data. IBKR's current path for corporate events is the Wall Street Horizon methods reqWshMetaData and reqWshEventData, which cover earnings dates, dividends, splits, and conferences⁶. A bot that depended on reqFundamentalData for ratios needs an external fundamentals source after upgrading.

The `$LEDGER-` per-currency prefix

The second behavior change is opt-in but easy to trip over. 10.47 adds an API setting, "Prepend '$LEDGER-' prefix to per-currency account values"²⁴. It fixes a long-standing ambiguity: a key like CashBalance appeared both at the overall-account level and inside each currency ledger, with no way to tell them apart. With the setting on, per-currency keys become $LEDGER-CashBalance and so on, while account-level keys stay bare²⁴. The default is what bites you: off for upgrading users, on for new users²⁴. Two installs of the same bot can therefore parse different account-value keys depending on install age. Affected calls are reqAccountUpdates and reqAccountUpdatesMulti².

What changed in 10.46

Between the 10.45 stable and 10.47 latest, 10.46 added market-data ticks rather than breaking anything²:

Odd-lot tick types: oddLotBid = 105, oddLotAsk = 106, oddLotBidSize = 107, oddLotAskSize = 108².
Support for requesting generic tick 787².

These are additive: existing tick handling keeps working, and the new ticks are available if you subscribe to them. The production notes also record a 10.48 entry — reqOpenOrders now includes de-activated orders — beyond the 10.47 latest-channel headline².

Rate limits in 2026: no change

A frequent question around any API bump is whether the pacing rules moved. For TWS API in 2026 they did not. The client-to-TWS ceiling is still 50 messages per second, and a sustained breach still ends in TWS closing the connection⁵. Historical-data pacing is also unchanged: at most 60 requests per 10-minute window, no 6+ requests for the same contract/exchange/tick type within 2 seconds, no identical request repeated within 15 seconds, BID_ASK counted double, and 50 simultaneous open historical requests⁵. For the full pacing playbook see IBKR TWS API Rate Limits 2026; for the cost side see Interactive Brokers API Pricing 2026.

Upgrade checklist

Audit for reqFundamentalData and its cancel/protobuf variants and the FUNDAMENTAL_RATIOS tick; route those to an external fundamentals feed before moving to 10.47²³.
Pin the $LEDGER- setting explicitly in your build runbook so every install parses the same keys, rather than relying on the upgrade-vs-new default²⁴.
Stay on 10.45 stable for non-Python clients that read fundamentals until the migration is done; the Python download is already on 10.47¹.
Re-test account-value parsing against both prefixed and bare keys.
No throttle changes to re-tune — the 50/second and historical pacing rules carry over from the prior line⁵.

Verified figures

The 10.45 stable (Mar 30 2026) and 10.47 latest (May 20 2026) versions, the Python-on-latest channel split, the 10.47 fundamentals removal (reqFundamentalData and variants plus the FUNDAMENTAL_RATIOS = 47 tick), the $LEDGER- prefix setting and its upgrade-vs-new default, the 10.46 odd-lot ticks (105–108) and generic tick 787, and the unchanged 50/second and historical pacing limits were all verified against IBKR's own pages on 2026-06-17. The IBKR Campus changelog page returned 403 in-session; the version table is taken from the public TWS API download page and the public 2026 production release notes instead. Prices and per-exchange data subscriptions are not restated here; see the pricing article.

Connects to

IBKR TWS API Rate Limits 2026: the full pacing rules these updates leave intact.
Interactive Brokers API Pricing 2026: the cost side of the same API.
Alpaca vs Interactive Brokers API 2026: pacing model versus a flat per-minute cap.
Broker API Comparator: IBKR's surface against other brokers.

References

Interactive Brokers. "TWS API" download page (Stable: API 10.45, Release Date Mar 30 2026; Latest: API 10.47, Release Date May 20 2026; Python included on the latest channel). interactivebrokers.github.io, verified 2026-06-16. https://interactivebrokers.github.io/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
Interactive Brokers. "Trader Workstation (TWS) 2026 API Production Release Notes" (10.47 removes reqFundamentalData/reqFundamentalsDataProtoBuf/cancelFundamentalData/cancelFundamentalsDataProtoBuf and the related callbacks/tick types; adds the "$LEDGER-" per-currency prefix setting affecting reqAccountUpdates/reqAccountUpdatesMulti, disabled by default for upgrading users and enabled for new users; 10.46 adds odd-lot ticks 105–108 and generic tick 787; 10.48 reqOpenOrders includes de-activated orders). ibkrguides.com, verified 2026-06-16. https://www.ibkrguides.com/releasenotes/prod-2026.htm ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶
Interactive Brokers / industry coverage. "TWS API 10.47" (removed reqFundamentalData, reqFundamentalsDataProtoBuf, cancelFundamentalData, cancelFundamentalsDataProtoBuf, the fundamentalData callbacks, and tick type FUNDAMENTAL_RATIOS = 47). reelfinancial.com, verified 2026-06-16. https://www.reelfinancial.com/archives/98837 ↩ ↩² ↩³
FX News Group. "Interactive Brokers updates TWS API" (10.47: new "Prepend '$LEDGER-' prefix to per-currency account values" setting; keys become e.g. "$LEDGER-CashBalance"; disabled by default for existing users, enabled for new ones). fxnewsgroup.com, verified 2026-06-16. https://fxnewsgroup.com/forex-news/retail-forex/interactive-brokers-updates-tws-api-2/ ↩ ↩² ↩³ ↩⁴ ↩⁵
Interactive Brokers. "TWS API - Historical Data Limitations" (60 requests / 10 minutes, 6 same-contract requests / 2 seconds, identical request within 15 seconds, BID_ASK counts double, 50 max simultaneous open requests; the 50 messages/second client cap is documented in the TWS API introduction). interactivebrokers.github.io, verified 2026-06-16. https://interactivebrokers.github.io/tws-api/historical_limitations.html ↩ ↩² ↩³ ↩⁴
Interactive Brokers. "TWS API - Fundamental Data" (current corporate-event path uses reqWshMetaData and reqWshEventData for earnings, dividends, splits, spinoffs, and conferences). interactivebrokers.github.io, verified 2026-06-16. https://interactivebrokers.github.io/tws-api/fundamentals.html ↩

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	schwab
results › row 1 › broker › name	Schwab
results › row 1 › broker › url	https://www.schwab.com/
results › row 1 › broker › docs url	https://developer.schwab.com/
results › row 1 › broker › auth	OAuth 2.0 (3-legged)
results › row 1 › broker › auth complexity	4
results › row 1 › broker › order types (9 items)	[...]
results › row 1 › broker › rate limits	120 req/min per endpoint (published tier)
results › row 1 › broker › market data › row 1	Real-time equities + options quotes
results › row 1 › broker › market data › row 2	Historical bars (1m to daily)
results › row 1 › broker › market data › row 3	No exchange depth via API
results › row 1 › broker › mcp	none
results › row 1 › broker › mcp note	No official or listed community MCP server
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	false
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	$0 equities, $0.65/contract options
results › row 1 › broker › good for	Established retail, post-TDA API migration
results › row 1 › broker › has free tier	true
results › row 1 › broker › notes › row 1	API rebuilt after TD Ameritrade integration; still maturing
results › row 1 › broker › notes › row 2	Requires individual developer registration and app review
results › row 1 › broker › notes › row 3	Token refresh flow is finicky vs Alpaca/Tradier
results › row 1 › score	2
results › row 1 › max score	2
results › row 1 › fits	true
results › row 2 › broker › id	ibkr
results › row 2 › broker › name	Interactive Brokers
results › row 2 › broker › url	https://www.interactivebrokers.com/
results › row 2 › broker › docs url	https://www.interactivebrokers.com/en/trading/ib-api.php
results › row 2 › broker › auth	OAuth + TWS/IB Gateway
results › row 2 › broker › auth complexity	5
results › row 2 › broker › order types (10 items)	[...]
results › row 2 › broker › rate limits	~50 msg/sec per connection; 50 orders/sec burst
results › row 2 › broker › market data › row 1	Global equities via subscription bundles
results › row 2 › broker › market data › row 2	Level-2 depth on most exchanges
results › row 2 › broker › market data › row 3	Historical depth across asset classes
results › row 2 › broker › mcp	community
results › row 2 › broker › mcp note	Community CLI MCP; audit before production
results › row 2 › broker › assets › stocks	true
results › row 2 › broker › assets › options	true
results › row 2 › broker › assets › futures	true
results › row 2 › broker › assets › crypto	true
results › row 2 › broker › assets › forex	true
results › row 2 › broker › assets › bonds	true
results › row 2 › broker › account minimum	0
results › row 2 › broker › commission	Tiered per-share or fixed; ~$0.0035/sh tiered
results › row 2 › broker › good for	Multi-asset-class, international, scale
results › row 2 › broker › has free tier	false
results › row 2 › broker › notes › row 1	Requires TWS or IB Gateway running locally
results › row 2 › broker › notes › row 2	Idempotency via client-supplied orderId
results › row 2 › broker › notes › row 3	Fully headless gateway is possible but under-documented
results › row 2 › score	2
results › row 2 › max score	2
results › row 2 › fits	true
results › row 3 › broker › id	alpaca
results › row 3 › broker › name	Alpaca
results › row 3 › broker › url	https://alpaca.markets/
results › row 3 › broker › docs url	https://alpaca.markets/docs/
results › row 3 › broker › auth	API Key + Secret
results › row 3 › broker › auth complexity	1
results › row 3 › broker › order types (10 items)	[...]
results › row 3 › broker › rate limits	200 req/min (free), higher on paid tiers
results › row 3 › broker › market data › row 1	IEX real-time (free)
results › row 3 › broker › market data › row 2	Full SIP on Algo Trader Plus ($99/mo)
results › row 3 › broker › market data › row 3	Historical bars + trades + quotes
results › row 3 › broker › mcp	official
results › row 3 › broker › mcp note	Official MCP V2, 61 actions, idempotent order submission
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	true
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 (PFOF on equities)
results › row 3 › broker › good for	Solo AI operator, paper-to-live parity
results › row 3 › broker › has free tier	true
results › row 3 › broker › notes › row 1	Free paper trading with same API surface as live
results › row 3 › broker › notes › row 2	Options require Algo Trader Plus tier
results › row 3 › broker › notes › row 3	Python/Go SDKs mature; rate-limit backoff documented
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	tradier
results › row 4 › broker › name	Tradier
results › row 4 › broker › url	https://tradier.com/
results › row 4 › broker › docs url	https://developer.tradier.com/
results › row 4 › broker › auth	OAuth 2.0
results › row 4 › broker › auth complexity	3
results › row 4 › broker › order types (8 items)	[...]
results › row 4 › broker › rate limits	120 req/min market data, 60 req/min trading
results › row 4 › broker › market data › row 1	Real-time equities + options (streaming)
results › row 4 › broker › market data › row 2	Historical OHLC back ~5 years
results › row 4 › broker › market data › row 3	No Level-2 depth
results › row 4 › broker › mcp	community
results › row 4 › broker › mcp note	Community MCP; idempotency is a manual patch
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	false
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 equities (PFOF), $0.35/contract options Pro
results › row 4 › broker › good for	Options-first retail, multi-leg strategies
results › row 4 › broker › has free tier	true
results › row 4 › broker › notes › row 1	Free sandbox with delayed data
results › row 4 › broker › notes › row 2	Strong options chain + multi-leg order API
results › row 4 › broker › notes › row 3	US-only account eligibility
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	robinhood
results › row 5 › broker › name	Robinhood
results › row 5 › broker › url	https://robinhood.com/
results › row 5 › broker › docs url	https://docs.robinhood.com/
results › row 5 › broker › auth	OAuth 2.0 (unofficial endpoints)
results › row 5 › broker › auth complexity	4
results › row 5 › broker › order types › row 1	market
results › row 5 › broker › order types › row 2	limit
results › row 5 › broker › order types › row 3	stop
results › row 5 › broker › order types › row 4	stop-limit
results › row 5 › broker › order types › row 5	gtc
results › row 5 › broker › order types › row 6	ioc
results › row 5 › broker › rate limits	Not publicly documented; low throughput
results › row 5 › broker › market data › row 1	Delayed quotes in public tier
results › row 5 › broker › market data › row 2	Limited historical depth
results › row 5 › broker › market data › row 3	No public Level-2
results › row 5 › broker › mcp	none
results › row 5 › broker › mcp note	No MCP; unofficial SDKs only
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	true
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 (PFOF), $5/mo Gold for margin + extras
results › row 5 › broker › good for	Casual retail; not recommended for agents
results › row 5 › broker › has free tier	true
results › row 5 › broker › notes › row 1	No officially supported public API in 2026
results › row 5 › broker › notes › row 2	Community SDKs break on auth changes without notice
results › row 5 › broker › notes › row 3	Paper trading unavailable
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	schwab
fitting brokers › row 1 › broker › name	Schwab
fitting brokers › row 1 › broker › url	https://www.schwab.com/
fitting brokers › row 1 › broker › docs url	https://developer.schwab.com/
fitting brokers › row 1 › broker › auth	OAuth 2.0 (3-legged)
fitting brokers › row 1 › broker › auth complexity	4
fitting brokers › row 1 › broker › order types (9 items)	[...]
fitting brokers › row 1 › broker › rate limits	120 req/min per endpoint (published tier)
fitting brokers › row 1 › broker › market data › row 1	Real-time equities + options quotes
fitting brokers › row 1 › broker › market data › row 2	Historical bars (1m to daily)
fitting brokers › row 1 › broker › market data › row 3	No exchange depth via API
fitting brokers › row 1 › broker › mcp	none
fitting brokers › row 1 › broker › mcp note	No official or listed community MCP server
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	false
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	$0 equities, $0.65/contract options
fitting brokers › row 1 › broker › good for	Established retail, post-TDA API migration
fitting brokers › row 1 › broker › has free tier	true
fitting brokers › row 1 › broker › notes › row 1	API rebuilt after TD Ameritrade integration; still maturing
fitting brokers › row 1 › broker › notes › row 2	Requires individual developer registration and app review
fitting brokers › row 1 › broker › notes › row 3	Token refresh flow is finicky vs Alpaca/Tradier
fitting brokers › row 1 › score	2
fitting brokers › row 1 › max score	2
fitting brokers › row 1 › fits	true
fitting brokers › row 2 › broker › id	ibkr
fitting brokers › row 2 › broker › name	Interactive Brokers
fitting brokers › row 2 › broker › url	https://www.interactivebrokers.com/
fitting brokers › row 2 › broker › docs url	https://www.interactivebrokers.com/en/trading/ib-api.php
fitting brokers › row 2 › broker › auth	OAuth + TWS/IB Gateway
fitting brokers › row 2 › broker › auth complexity	5
fitting brokers › row 2 › broker › order types (10 items)	[...]
fitting brokers › row 2 › broker › rate limits	~50 msg/sec per connection; 50 orders/sec burst
fitting brokers › row 2 › broker › market data › row 1	Global equities via subscription bundles
fitting brokers › row 2 › broker › market data › row 2	Level-2 depth on most exchanges
fitting brokers › row 2 › broker › market data › row 3	Historical depth across asset classes
fitting brokers › row 2 › broker › mcp	community
fitting brokers › row 2 › broker › mcp note	Community CLI MCP; audit before production
fitting brokers › row 2 › broker › assets › stocks	true
fitting brokers › row 2 › broker › assets › options	true
fitting brokers › row 2 › broker › assets › futures	true
fitting brokers › row 2 › broker › assets › crypto	true
fitting brokers › row 2 › broker › assets › forex	true
fitting brokers › row 2 › broker › assets › bonds	true
fitting brokers › row 2 › broker › account minimum	0
fitting brokers › row 2 › broker › commission	Tiered per-share or fixed; ~$0.0035/sh tiered
fitting brokers › row 2 › broker › good for	Multi-asset-class, international, scale
fitting brokers › row 2 › broker › has free tier	false
fitting brokers › row 2 › broker › notes › row 1	Requires TWS or IB Gateway running locally
fitting brokers › row 2 › broker › notes › row 2	Idempotency via client-supplied orderId
fitting brokers › row 2 › broker › notes › row 3	Fully headless gateway is possible but under-documented
fitting brokers › row 2 › score	2
fitting brokers › row 2 › max score	2
fitting brokers › row 2 › fits	true

Computed live at build time.

Frequently asked questions

What is the latest Interactive Brokers TWS API version in 2026?: TWS API 10.47, released May 20 2026, is the latest channel and the first 2026 line with Python API binaries. The stable channel is 10.45, released Mar 30 2026 (verified 2026-06-16).
What did TWS API 10.47 remove?: It removed the legacy fundamentals path: reqFundamentalData, reqFundamentalsDataProtoBuf, cancelFundamentalData, cancelFundamentalsDataProtoBuf, their callbacks, and the FUNDAMENTAL_RATIOS = 47 tick type. Code calling these stops returning data on a 10.47 client.
What is the $LEDGER- prefix in TWS API 10.47?: A new API setting that prepends $LEDGER- to per-currency account-value keys (e.g. $LEDGER-CashBalance) so they are distinct from account-level keys. It is off by default for upgrading users and on for new users, and it affects reqAccountUpdates and reqAccountUpdatesMulti.
Did the IBKR API rate limits change in the 2026 updates?: No. The 50 messages/second client cap and the historical-data pacing rules (60 per 10 minutes, 6 per 2 seconds for the same contract, no identical request within 15 seconds, BID_ASK counted double, 50 simultaneous open requests) carry over unchanged (verified 2026-06-16).