Time to Stable

For a given set of browsers, what APIs are in all of them and how many days it take for the API to land in the first browser to the last.

Example Comparisons
Browsers
Features

Summary

A count of the number of APIs that landed in A first and B last.
Last in ChromeLast in Firefox
First in Chrome 34
First in Firefox 37

Average time for an API to become available across Chrome and Firefox

71 APIs took an average of 100.44 days to become available to use.

API breakdown:

Average time to landing by year of first landing

If a feature landed in the earliest browser in 20XX it took Y days on average to become available in the last browser (when considering Chrome and Firefox). TTA (time to available).
WebAssembly APIsWebAssembly TTA
2017 3014.00
2018 725.86
2019 3429.33
2020 3214.33
2021 10177.10
2023 7264.00
2024 8103.25
2025 351.33

The Tortoise and the Hare

There is a natural tension on the web with respect to browser engines. Every engine has their own set of priorities which define the level of investment that they choose to make and on which areas they choose to make it.

A developer naturally wants their experiences to be available to the widest audience possible and these differing priorities create an unevenness on the platform (a lumpiness) making it harder for developers to build experiences that work everywhere.

This section highlights where browsers are pushing and pulling on the platform.

Sprinters

This table is designed to show which browsers are pushing on the platform the most.

Adding features to quickly is not always desired because developers are unlikely to adopt those features in their sites or apps.

For a given year, if a feature landed in Browser X first, how many days it take on average to be available in Chrome and Firefox. TTA (time to available).
Year WebAssemblyWebAssembly TTA
2017
  Firefox 282.00
  Chrome 2182.00
2018
  Chrome 61.00
  Firefox 1175.00
2019
  Chrome 3429.33
2020
  Firefox 3214.33
2021
  Chrome 10177.10
2023
  Chrome 6299.83
  Firefox 149.00
2024
  Chrome 784.00
  Firefox 1238.00
2025
  Firefox 351.33

Plodders

This table is designed to show which browsers are pulling on the platform the most.

For a feature that first landed in year X, how many days did it take on average for the last browser to catch up across Chrome and Firefox. TTA (time to available).
Year WebAssembly countWebAssembly TTA
2017
  Chrome 282.00
  Firefox 2182.00
2018
  Firefox 61.00
  Chrome 1175.00
2019
  Firefox 3429.33
2020
  Chrome 3214.33
2021
  Firefox 10177.10
2023
  Firefox 6299.83
  Chrome 149.00
2024
  Firefox 784.00
  Chrome 1238.00
2025
  Chrome 351.33

Stable APIs

Below is a list of features that are in Chrome and Firefox

Raw Data

Quick Links:

WebAssembly Data

API First Browser Date Last Browser Date Days Notes
webassembly.BigInt-to-i64-integration 📋Firefox6/30/2020 Chrome8/25/202056
webassembly.api 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.CompileError 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.CompileError.CompileError 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Exception 📋Chrome10/19/2021 Firefox5/3/2022196
webassembly.api.Exception.Exception 📋Chrome10/19/2021 Firefox5/3/2022196
webassembly.api.Exception.Exception.options_parameter_traceStack Chrome10/19/2021 Firefox5/3/2022196
webassembly.api.Exception.getArg 📋Chrome10/19/2021 Firefox5/3/2022196
webassembly.api.Exception.is 📋Chrome10/19/2021 Firefox5/3/2022196
webassembly.api.Exception.stack Chrome10/19/2021 Firefox5/3/2022196
webassembly.api.Global 📋Chrome9/4/2018 Firefox9/5/20181
webassembly.api.Global.Global 📋Chrome9/4/2018 Firefox9/5/20181
Chrome: Constructing a Global with a value of v128 produces a TypeError.Chrome Android: Constructing a Global with a value of v128 produces a TypeError.Deno: Constructing a Global with a value of v128 produces a TypeError.Edge: Constructing a Global with a value of v128 produces a TypeError.Node.js: Constructing a Global with a value of v128 produces a TypeError.Quest Browser: Constructing a Global with a value of v128 produces a TypeError.Opera: Constructing a Global with a value of v128 produces a TypeError.Opera Android: Constructing a Global with a value of v128 produces a TypeError.Samsung Internet: Constructing a Global with a value of v128 produces a TypeError.WebView Android: Constructing a Global with a value of v128 produces a TypeError.
webassembly.api.Global.value 📋Chrome9/4/2018 Firefox9/5/20181
webassembly.api.Global.valueOf 📋Chrome9/4/2018 Firefox9/5/20181
webassembly.api.Instance 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Instance.Instance 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Instance.exports 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.JSTag_static 📋Chrome7/18/2023 Firefox10/1/2024441
webassembly.api.LinkError 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.LinkError.LinkError 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Memory 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Memory.Memory 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Memory.Memory.shared 📋Chrome4/23/2019 Firefox6/30/2020434
Safari: Shared WebAssembly.Memory is gated behind COOP/COEP. For more detail, read Making your website "cross-origin isolated" using COOP and COEP.Safari on iOS: Shared WebAssembly.Memory is gated behind COOP/COEP. For more detail, read Making your website "cross-origin isolated" using COOP and COEP.WebView on iOS: Shared WebAssembly.Memory is gated behind COOP/COEP. For more detail, read Making your website "cross-origin isolated" using COOP and COEP.
webassembly.api.Memory.buffer 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Memory.grow 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Memory.toFixedLengthBuffer 📋Firefox11/11/2025 Chrome1/13/202663
webassembly.api.Memory.toResizableBuffer 📋Firefox11/11/2025 Chrome1/13/202663
webassembly.api.Module 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Module.Module 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Module.Module.compile_options 📋Chrome10/15/2024 Firefox1/7/202584
webassembly.api.Module.customSections_static 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Module.exports_static 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Module.imports_static 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.RuntimeError 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.RuntimeError.RuntimeError 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Table 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Table.Table 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Table.get 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Table.grow 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Table.length 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Table.set 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.Tag 📋Chrome10/19/2021 Firefox5/3/2022196
webassembly.api.Tag.Tag 📋Chrome10/19/2021 Firefox5/3/2022196
webassembly.api.compileStreaming_static 📋Chrome7/25/2017 Firefox1/23/2018182
webassembly.api.compileStreaming_static.compile_options 📋Chrome10/15/2024 Firefox1/7/202584
webassembly.api.compile_static 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.compile_static.compile_options 📋Chrome10/15/2024 Firefox1/7/202584
webassembly.api.instantiateStreaming_static 📋Chrome7/25/2017 Firefox1/23/2018182
webassembly.api.instantiateStreaming_static.compile_options 📋Chrome10/15/2024 Firefox1/7/202584
webassembly.api.instantiate_static 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.instantiate_static.compile_options 📋Chrome10/15/2024 Firefox1/7/202584
webassembly.api.validate_static 📋Firefox3/7/2017 Chrome3/9/20172
webassembly.api.validate_static.compile_options 📋Chrome10/15/2024 Firefox1/7/202584
webassembly.bulk-memory-operations 📋Chrome6/4/2019 Firefox6/30/2020392
webassembly.exception-handling 📋Chrome10/19/2021 Firefox5/3/2022196
webassembly.exceptionsFinal 📋Firefox10/1/2024 Chrome5/27/2025238
webassembly.extended-constant-expressions 📋Firefox4/11/2023 Chrome5/30/202349
webassembly.fixed-width-SIMD 📋Chrome5/25/2021 Firefox6/1/20217
webassembly.garbage-collection 📋Chrome10/31/2023 Firefox11/21/202321
webassembly.jsStringBuiltins 📋Chrome10/15/2024 Firefox1/7/202584
webassembly.memory64 📋Firefox1/7/2025 Chrome2/4/202528
webassembly.multi-value 📋Firefox6/30/2020 Chrome10/20/2020112
webassembly.multiMemory 📋Chrome12/5/2023 Firefox4/16/2024133
webassembly.mutable-globals 📋Chrome9/4/2018 Firefox9/5/20181
webassembly.non-trapping-float-to-int-conversions 📋Firefox12/11/2018 Chrome6/4/2019175
webassembly.reference-types 📋Firefox7/28/2020 Chrome11/15/2021475
webassembly.relaxed-SIMD 📋Chrome5/30/2023 Firefox12/9/2025924
webassembly.sign-extension-operations 📋Chrome9/4/2018 Firefox9/5/20181
webassembly.tail-calls 📋Chrome4/4/2023 Firefox12/19/2023259
webassembly.threads-and-atomics 📋Chrome4/23/2019 Firefox7/28/2020462
webassembly.typedFunctionReferences 📋Chrome10/31/2023 Firefox11/21/202321