blog.mozilla.org/addons

https://blog.mozilla.org/addons

Ranks Overall #979 Built Awesome #704

Data from Oct 3, 2026, 1:46 AM UTC 5d old Measured once a week · 7 runs since Aug 20, 2026

Elsewhere: PageSpeed Insights · Calibre · Treo · CrUX Vis · Tame the Bots · Scoring Calculator · Wayback Machine

This URL redirects to https://blog.mozilla.org/addons/.

The same URL in a different form — a trailing slash — so both are treated as one site rather than two: one history, measured once. Lighthouse follows the redirect, so the numbers below describe the page actually served; the only cost is an extra hop on each run.

Lab data is measured using Lighthouse, Mobile mode unless otherwise specified. Field data is reported from Chrome UX Report (using p75 measurements).

Stack

Hosted by Cloudflare

Lighthouse Scores LAB Simulated

Performance

↓ -3 (-3.1%)

Accessibility

no change

100

Best Practices

no change

SEO

no change

Metrics LAB FIELD

Core Web Vitals: passing 3 of 3 assessed from real Chrome users.

Field figures are the p75 across real Chrome users over a 28-day trailing window (2026-09-02 → 2026-09-29), origin-level.

Metric	Lab Simulated	Field
LCP CWV Largest Contentful Paint	2.85 s needs work	↑ +1181 ms (+70.6%) 1.67 s – 3.74 s	1.62 s good	88.7% 5.7% 5.5%
INP CWV Interaction to Next Paint — field only, no lab run can measure it	n/a	—	122 ms good	87% 9.7% 3.3%
CLS CWV Cumulative Layout Shift	0.026 good	↑ +0.001 (+4%) 0.025 – 0.026	0 good	95% 3.4% 1.6%
TBT Total Blocking Time	132 ms good	↓ -23 ms (-14.8%) 75 ms – 155 ms	n/a	—
FCP First Contentful Paint	1.35 s good	↓ -259 ms (-16.1%) 1.31 s – 2.37 s	1.57 s good	80.7% 11.4% 7.9%
Speed Index	1.36 s good	↓ -245 ms (-15.2%) 1.31 s – 2.37 s	n/a	—
TTFB Time to First Byte	484 ms good	↑ +11 ms (+2.3%) 465 ms – 484 ms	1.10 s needs work	61.6% 27.4% 11%

Metric

Lab Simulated

Field

Value

Change / range

Trend

p75

Distribution

LCP CWV Largest Contentful Paint

2.85 s needs work

↑ +1181 ms (+70.6%) 1.67 s – 3.74 s

1.62 s good

88.7% 5.7% 5.5%

INP CWV Interaction to Next Paint — field only, no lab run can measure it

n/a

—

122 ms good

87% 9.7% 3.3%

CLS CWV Cumulative Layout Shift

0.026 good

↑ +0.001 (+4%) 0.025 – 0.026

0 good

95% 3.4% 1.6%

TBT Total Blocking Time

132 ms good

↓ -23 ms (-14.8%) 75 ms – 155 ms

n/a

—

FCP First Contentful Paint

1.35 s good

↓ -259 ms (-16.1%) 1.31 s – 2.37 s

1.57 s good

80.7% 11.4% 7.9%

Speed Index

1.36 s good

↓ -245 ms (-15.2%) 1.31 s – 2.37 s

n/a

—

TTFB Time to First Byte

484 ms good

↑ +11 ms (+2.3%) 465 ms – 484 ms

1.10 s needs work

61.6% 27.4% 11%

LCP Subparts LAB Unthrottled

The subparts attribute LCP to your server, resource discovery, download, or rendering. Note that the Lab LCP shown above is a simulated throttled estimate.

time to first byte 362 ms

resource load delay 73 ms

element render delay 36 ms

resource load duration 32 ms

LCP LAB Simulated vs LCP FIELD

Lab 2.85 s

Field p75 1.62 s

The lab LCP is 1.76× the field p75 — real users likely have above-average hardware or network connectivity.

Page weight

Metric	Value	Change / range
Page Weight	352 kB	↑ +1.7 kB (+0.5%) 345 kB – 352 kB
Requests	22	→ no change 22 – 22
Third-party Weight	171 kB	↑ +1.7 kB (+1%) 164 kB – 171 kB
Third-party CPU	54 ms	↓ -3 ms (-5.8%) 51 ms – 57 ms
Unused JS	74.5 kB	↑ +3.4 kB (+5%) significant 71.0 kB – 74.5 kB
Unused CSS	14.2 kB	→ no change 14.2 kB – 14.2 kB

Metric

Value

Change / range

Trend

Page Weight

352 kB

↑ +1.7 kB (+0.5%) 345 kB – 352 kB

Requests

→ no change 22 – 22

Third-party Weight

171 kB

↑ +1.7 kB (+1%) 164 kB – 171 kB

Third-party CPU

54 ms

↓ -3 ms (-5.8%) 51 ms – 57 ms

Unused JS

74.5 kB

↑ +3.4 kB (+5%) significant 71.0 kB – 74.5 kB

Unused CSS

14.2 kB

→ no change 14.2 kB – 14.2 kB

By resource type

Type	Share	Size	Requests
script	60.5%	213 kB	6
font	19.9%	70.2 kB	3
image	8.2%	28.7 kB	7
stylesheet	7.9%	27.8 kB	3
document	3.2%	11.4 kB	1
other	0.3%	893 B	2
Total		352 kB	22

Third parties 1 entities

Entity	Transfer	Size	Main thread Simulated
Google Tag Manager	script	171 kB	54 ms
Total		171 kB	54 ms

Entity

Transfer

Size

Main thread Simulated

Google Tag Manager

script

171 kB

54 ms

Total

171 kB

54 ms

Page health

Metric	Value	Change / range
Main Thread Work	721 ms	↓ -4 ms (-0.6%) 638 ms – 756 ms
Long Tasks	3	→ no change 3 – 3
DOM Elements	575	→ no change 575 – 575
Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports)	5	→ no change 5 – 5
A11y Failures	2	→ no change 2 – 2
A11y Failing Nodes	3	→ no change 3 – 3

Metric

Value

Change / range

Trend

Main Thread Work

721 ms

↓ -4 ms (-0.6%) 638 ms – 756 ms

Long Tasks

→ no change 3 – 3

DOM Elements

575

→ no change 575 – 575

Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports)

→ no change 5 – 5

A11y Failures

→ no change 2 – 2

A11y Failing Nodes

→ no change 3 – 3

Main thread work

Task	Share	Duration Simulated
script evaluation	34%	249 ms
other	27%	193 ms
style layout	21%	151 ms
script parse compile	8%	57 ms
parse HTML	4%	29 ms
paint composite render	4%	28 ms
garbage collection	2%	15 ms
Total		721 ms

Task

Time

Duration Simulated

script evaluation

34%

249 ms

other

27%

193 ms

style layout

21%

151 ms

script parse compile

57 ms

parse HTML

29 ms

paint composite render

28 ms

garbage collection

15 ms

Total

721 ms

Axe violations axe-core 4.13.0, full rule set

5 violating nodes across 3 rules, 544 passing. This is a standalone Axe CLI run and is stricter than the subset Lighthouse already includes.

moderate landmark-unique — Landmarks should have a unique role or role/label/title (i.e. accessible name) combination 2 nodes
Offending elements
1. #nav-global
```
<nav id="nav-global" class="nav-global can-stick">
```
2. #sidebar
```
<aside id="sidebar" class="section widgets can-stick is-active" style="display: block;">
```

serious link-in-text-block — Links must be distinguishable without relying on color 2 nodes

Offending elements

a[href$="foundation.mozilla.org"]

<a href="https://foundation.mozilla.org" data-link-type="footer" data-link-name="Mozilla Foundation">Mozilla Foundation</a>

a[rel="external license"]

<a href="https://www.mozilla.org/foundation/licensing/website-content/" rel="external license">Creative Commons license</a>

moderate heading-order — Heading levels should only increase by one 1 node

Offending element

.mozilla > h5

<h5><a href="https://www.mozilla.org/?utm_source=blog.mozilla.org&amp;utm_campaign=footer&amp;utm_medium=referral" data-link-type="footer" data-link-name="Mozilla">Mozilla</a></h5>

Accessibility failures 2 of 26 audits

link-in-text-block — Links rely on color to be distinguishable. 2 nodes
heading-order — Heading elements are not in a sequentially-descending order 1 node

SEO failures 2 of 9 audits

meta-description — Document does not have a meta description
link-text — Links do not have descriptive text 9 items

Hygiene

HTTPS HSTS CSP Clickjacking protection Origin isolation Trusted Types bfcache h2

Measurement log

Field history 25 weeks

Weekly p75 from the CrUX History API, backfilled in a single request.

Week ending	LCP	INP	FCP	TTFB
2026-09-26	1.61 s	121 ms	1.55 s	1.09 s
2026-09-19	1.58 s	124 ms	1.51 s	1.04 s
2026-09-12	1.36 s	110 ms	1.30 s	842 ms
2026-09-05	1.37 s	109 ms	1.30 s	846 ms
2026-08-29	1.40 s	111 ms	1.33 s	877 ms
2026-08-22	1.42 s	108 ms	1.35 s	902 ms
2026-08-15	1.56 s	120 ms	1.50 s	1.07 s
2026-08-08	1.56 s	118 ms	1.50 s	1.06 s
2026-08-01	1.54 s	115 ms	1.47 s	1.01 s
2026-07-25	1.57 s	115 ms	1.49 s	1.02 s
2026-07-18	1.68 s	115 ms	1.59 s	1.13 s
2026-07-11	1.63 s	107 ms	1.56 s	1.09 s

Week ending

LCP

INP

CLS

FCP

TTFB

2026-09-26

1.61 s

121 ms

1.55 s

1.09 s

2026-09-19

1.58 s

124 ms

1.51 s

1.04 s

2026-09-12

1.36 s

110 ms

1.30 s

842 ms

2026-09-05

1.37 s

109 ms

1.30 s

846 ms

2026-08-29

1.40 s

111 ms

1.33 s

877 ms

2026-08-22

1.42 s

108 ms

1.35 s

902 ms

2026-08-15

1.56 s

120 ms

1.50 s

1.07 s

2026-08-08

1.56 s

118 ms

1.50 s

1.06 s

2026-08-01

1.54 s

115 ms

1.47 s

1.01 s

2026-07-25

1.57 s

115 ms

1.49 s

1.02 s

2026-07-18

1.68 s

115 ms

1.59 s

1.13 s

2026-07-11

1.63 s

107 ms

1.56 s

1.09 s

Runs

Every stored run for this URL, newest first.

When	Perf	LCP	CLS	TBT	Weight	Runs	Spread	Bench	Took	Archive
Oct 3, 2026, 1:46 AM UTC	94	2.85 s	0.026	132 ms	352 kB	3/3	±14	2,764 +11%	24.3s	Wayback
Sep 25, 2026, 11:16 AM UTC	97	1.67 s	0.025	155 ms	351 kB	3/3	±5	2,491 0%	24.2s	Wayback
Sep 18, 2026, 8:48 AM UTC	86	3.73 s	0.025	75 ms	350 kB	3/3	±33	2,632 +6%	24.5s	Wayback
Sep 11, 2026, 8:37 AM UTC	92	3.17 s	0.025	139 ms	349 kB	3/3	±47	2,640 +6%	27.1s	Wayback
Sep 4, 2026, 5:37 AM UTC	86	3.74 s	0.025	79 ms	349 kB	3/3	±33	2,835 +14%	23.8s	Wayback
Aug 28, 2026, 1:17 AM UTC	86	3.63 s	0.025	122 ms	346 kB	3/3	±34	2,466 -1%	24.7s	Wayback
Aug 20, 2026, 3:52 PM UTC	98	1.67 s	0.025	136 ms	345 kB	3/3	±17	2,328 -6%	24.4s	Wayback

When

Scores

Perf

LCP

CLS

TBT

Weight

Runs

Spread

Bench

Took

Embed this score

Use this web component to show blog.mozilla.org/addons's scores on any website, updated whenever this instance re-measures. Don’t forget to bundle the speedlify2-score.js component code into your site!

<speedlify2-score speedlify-url="https://www.speedlify.dev/" url="https://blog.mozilla.org/addons"></speedlify2-score>

Stack

Lighthouse Scores LAB 🤖 Simulated

Metrics LAB FIELD

LCP Subparts LAB 🐇 Unthrottled

LCP LAB 🤖 Simulated vs LCP FIELD

Page weight

By resource type

Third parties 1 entities

Page health

Main thread work

Axe violations axe-core 4.13.0, full rule set

Accessibility failures 2 of 26 audits

SEO failures 2 of 9 audits

Hygiene

Measurement log

Field history 25 weeks

Runs

Embed this score

Lighthouse Scores LAB Simulated

LCP Subparts LAB Unthrottled

LCP LAB Simulated vs LCP FIELD