Is the B123 MQL source code library free?

Yes. The source-code product pages are public and the source packages can be claimed through a registered B123 account with private zero-total order delivery and daily claim limits.

Do I receive editable MQ4 or MQ5 files?

The free-source products provide editable MQL derivatives when available, with page-level notes for platform, source format, dependencies, compile status, and detected code structure.

Why do some files show compile_failed or dependency_missing?

Some legacy MQL files require missing include files, unavailable custom indicators, older MetaEditor syntax, or manual platform-specific changes. Diagnostic labels are shown before download.

Can B123 fix, convert, or review a source file?

B123 can use the diagnostic label and dependency notes as a starting point for a support conversation, but no repair, conversion, trading result, or live-account outcome is guaranteed.

Free MQL4 & MQL5 Source Code Downloads

Q: What if I need a ready-to-use EA instead of source code?

Use the paid BBTrading paths when you want packaged tools, setup notes, private delivery, and available backtest evidence instead of editing or compiling raw source code yourself.

Browse free MQL source code for MetaTrader 4 and MetaTrader 5 through the B123 Quant library. The collections separate Expert Advisors from indicators and general download intent from editable MQ4 or MQ5 source-code intent, so traders can reach the most relevant platform and resource type quickly.

Source-code analysis only. No backtest or live-performance claim is provided.

Free MetaTrader source libraries

Use the general download collections to compare available resources, installation steps, platform compatibility, account access, and private delivery. Use the source-code collections when you want editable files, detected inputs, event handlers, dependencies, diagnostic status, and code-specific risk notes.

Free MT4 EA downloads for MetaTrader 4 Expert Advisor discovery and installation.
Free MT5 EA downloads for MetaTrader 5 Expert Advisor discovery and installation.
Free MT4 indicator downloads for editable MT4 indicator resources.
Free MT5 indicator downloads for MetaTrader 5 indicator resources.
Free MT4 EA source code with MQ4 structure and diagnostic evidence.
Free MT5 EA source code with MQ5 structure and diagnostic evidence.
Free MT4 indicator source code with buffers, inputs, and dependency notes.
Free MT5 indicator source code with MQ5 event and plot analysis.

How resources qualify for the public library

Original files remain immutable. A published derivative is created separately, non-runtime author URLs and contact details are replaced with the B123 site URL, and functional WebRequest or runtime API endpoints are preserved when changing them would alter behavior. Exact duplicates consolidate into one canonical family rather than creating repeated search pages.

Diagnostic status is shown so users know what may need work. A source can be marked compile passed, compile failed, dependency missing, legacy source, or compile not run. Compilation confirms only syntax and available dependencies in one isolated environment; it never proves trading performance or live-account suitability.

What each product page documents

Each family page identifies the platform, resource type, source format, detected handlers and components, exposed inputs, dependencies, sanitization status, compilation result, installation workflow, and operational risks supported by static evidence. Pages do not invent profit, drawdown, win rate, broker, symbol, timeframe, prop-firm, or non-repainting claims.

Private download access

Product pages and collection pages are public, while source packages use registered WooCommerce accounts and private download permissions. Each account may claim three distinct free-source products per site day. Each granted permission allows three download attempts and expires after 30 days. Raw ZIP paths, account pages, and private delivery endpoints are not search landing pages.

Need a ready-to-use EA instead of source code?

Free source is useful for study and testing, but it may require compilation, missing includes, syntax changes, broker-specific setup, or risk review. Traders who do not want to edit code can compare paid BBTrading products with clearer setup notes, private delivery, and available backtest evidence. Paid products are separate from this free library and should be evaluated on their own product evidence and risk notes.

Want this source checked or fixed?

If a file does not compile or you are unsure how to install it, use the diagnostic label and dependency list when contacting B123. A support conversation can identify whether the problem is a missing include, old MQL syntax, platform mismatch, or configuration issue. No repair or live-trading outcome is guaranteed.

Questions

Are these MQL files free to download?

Yes. A registered account is required so WooCommerce can grant a private zero-total order permission and enforce the daily quota.

Does a compile pass mean an EA is profitable?

No. Compilation checks code and dependencies only. It is not a backtest, live result, or profitability verification.

Why might a source file fail to compile?

Common causes include missing MQH dependencies, old language syntax, unavailable custom indicators, or differences between MetaEditor builds. The product page shows the known diagnostic status before download.

Can the source code be modified?

The downloadable MQ4 and MQ5 derivatives are editable, but every modification requires independent review, compilation, and demo testing.

Are functional API addresses removed?

No. Detected runtime endpoints are preserved when replacement could break WebRequest, licensing, news, or other executable network behavior.

179 matching source pages
Claim limit: 3 distinct free resources per account day
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