Slack is a cloud-based workplace messaging and collaboration platform founded in 2009 and headquartered in San Francisco.
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Slack has no independent sustainability reporting; all environmental data is buried in parent Salesforce's consolidated metrics. The company recently dropped absolute Scope 3 reduction targets in favor of intensity metrics—a hallmark greenwashing move. No Slack-specific emissions, waste, water, or nature data exists; renewable energy claims rest on market instruments, not additionality.
Slack scores 37/100 (Below expectations) on SINK's independent climate assessment, scored from public data only. Fees pay for the review, never the result. Last verified May 2026.
That places Slack joint 435th of 847 companies scored, and joint 41st of 76 in SaaS / Digital Services.
Where Slack sits among saas / digital services peers.
Among the 76 major saas / digital services brands we've scored, Slack is tied =41st of 76, with 5 others.
Its three lowest-scoring questions, and what the evidence didn't show.
Slack has no reported trajectory.
Slack has no nature or biodiversity policy.
No manufacturing or physical product lifecycle.
A score changes when the evidence does. We use new published evidence at the next rescore. Evidence that isn't public can count through an evidence review.
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Get in touch →Strongest on Energy Source and Carbon Footprint — Operations (6/10, 4/10). Weakest on Emissions Trajectory and Nature & Biodiversity Impact (3/10, 3/10).
The 3 companies in the sector scoring nearest above Slack.
Stripe publishes almost no corporate environmental data despite $5.1B revenue and 8,000 employees.
See the breakdown →Microsoft's emissions rose 25% in FY2025 to 21.1 Mt CO2e, driven by data-centre construction: capital-goods emissions rose from 5.6 Mt to 9.0 Mt and Scope 3 is 86% of the total.
See the breakdown →The formula and all 10 sources.
Same ten questions for every company. No private weighting.
SINK = (0.3 × Base + 0.7 × Performance) × Scale10 sources used in this assessment. All publicly available. Each row shows which of the ten questions it informed.
If you believe a source has been misread or a newer version exists, submit a challenge.
Slack is a cloud-based workplace messaging and collaboration platform founded in 2009 and headquartered in San Francisco. Acquired by Salesforce in July 2021, it serves millions of users globally. As a SaaS business, Slack has minimal direct environmental impact but lacks independent sustainability disclosure and operates under its parent's consolidated reporting.
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