nafyi.

Customer testimonials published by Anthropic for Claude Sonnet 5.5

Anthropic News ·

Anthropic’s Claude Sonnet 5.5 announcement includes named customer testimonials from Epic Games, Base44, Slack and Zendesk. These customers describe their own engineering, app-building, assistant and support tests. The accounts are selected and published by Anthropic; their reported results have not been independently verified by nafyi. Read 4 viewpoints with supporting evidence and source links.

Daniel VogelGabriel GrinbergCurtis AllenAbhinay Kathuria
Read key viewpointsOpen Publisher (opens in a new tab)

Understand this piece

4 key points

Synthesis

  1. Epic reports higher-tier quality on engineering tasks

    In a customer testimonial published by Anthropic, Epic Games’ Daniel Vogel says Sonnet 5.5 met the quality bar he expected from a higher-tier model in early system-design and data-flow reviews, while handling long engineering tasks with less prescriptive prompting.

    Supporting evidence 1

    Original excerpt

    “In Epic’s early testing, Claude Sonnet 5.5 cleared the same quality bar you’d expect from a higher-tier model, holding up on a system design audit and a data flow review. The new model managed tens of thousands of lines of code for gameplay system architecture, kept responses snappy, handled multi-hour tasks, and delivered with less prescriptive prompting.”

    Daniel Vogel · Source text block 30 · customer quotation

    Customer testimonials published by Anthropic for Claude Sonnet 5.5 · Sep 28, 2026

    Read in source context →

    Continue exploring

    Coding task quality →

  2. Base44 reports fewer iterations across 118 app builds

    In a customer testimonial published by Anthropic, Base44’s Gabriel Grinberg reports that Sonnet 5.5 matched Opus 5’s scores across 118 app builds, averaging 3.6 iterations per build versus 7.7 for Opus 5.

    Supporting evidence 1

    Original excerpt

    “Across 118 real app builds, Claude Sonnet 5.5 produced apps that scored level with Opus 5. It got there in 3.6 iterations per build on average, where Opus 5 took 7.7. It had the fewest failed tool calls of any model we compared. It also rarely stopped mid-build to ask the user a question, so fewer builds stall waiting on someone to answer.”

    Gabriel Grinberg · Source text block 34 · customer quotation

    Customer testimonials published by Anthropic for Claude Sonnet 5.5 · Sep 28, 2026

    Read in source context →

    Continue exploring

    Application building iterations →

  3. Slack reports better offline results with fewer tokens

    In a customer testimonial published by Anthropic, Slack’s Curtis Allen reports that Sonnet 5.5 outperformed Sonnet 5 on almost all of their offline Slackbot evaluations without prompt changes, using fewer steps and about 14% fewer output tokens.

    Supporting evidence 1

    Original excerpt

    “Without changing any of our prompts, Claude Sonnet 5.5 did better than Sonnet 5 on almost all of our offline Slackbot evals, in fewer steps and with about 14% fewer output tokens. When someone gives Slackbot a task, quality and speed are what matter most, and Sonnet 5.5 allows Slackbot to deliver better outcomes for users, faster.”

    Curtis Allen · Source text block 41 · customer quotation

    Customer testimonials published by Anthropic for Claude Sonnet 5.5 · Sep 28, 2026

    Read in source context →

    Continue exploring

    Assistant evaluation efficiency →

  4. Zendesk reports fewer wrong decisions and faster processing

    In a customer testimonial published by Anthropic, Zendesk’s Abhinay Kathuria says Sonnet 5.5 made fewer wrong decisions on hundreds of support use cases and processed tickets 20% faster than the Claude models Zendesk was using at the time.

    Supporting evidence 1

    Original excerpt

    “We fed Claude Sonnet 5.5 hundreds of real support use cases across replies and escalation requests. It made fewer wrong decisions and resolved tickets faster than the Claude models we use in production today. Tickets were processed 20% faster, getting our customers the help they need without the wait.”

    Abhinay Kathuria · Source text block 42 · customer quotation

    Customer testimonials published by Anthropic for Claude Sonnet 5.5 · Sep 28, 2026

    Read in source context →

    Continue exploring

    Customer support workflows →

Key passages4

Attributed passages with the context to verify them. Open the original text to check the source.

Source text block 34 · customer quotation (opens in a new tab)
Application building iterations

Base44 reports fewer iterations across 118 app builds

Original excerpt

“Across 118 real app builds, Claude Sonnet 5.5 produced apps that scored level with Opus 5. It got there in 3.6 iterations per build on average, where Opus 5 took 7.7. It had the fewest failed tool calls of any model we compared. It also rarely stopped mid-build to ask the user a question, so fewer builds stall waiting on someone to answer.”
Gabriel Grinberg·
Source text block 41 · customer quotation (opens in a new tab)
Assistant evaluation efficiency

Slack reports better offline results with fewer tokens

Original excerpt

“Without changing any of our prompts, Claude Sonnet 5.5 did better than Sonnet 5 on almost all of our offline Slackbot evals, in fewer steps and with about 14% fewer output tokens. When someone gives Slackbot a task, quality and speed are what matter most, and Sonnet 5.5 allows Slackbot to deliver better outcomes for users, faster.”
Curtis Allen·
Source text block 42 · customer quotation (opens in a new tab)
Customer support workflows

Zendesk reports fewer wrong decisions and faster processing

Original excerpt

“We fed Claude Sonnet 5.5 hundreds of real support use cases across replies and escalation requests. It made fewer wrong decisions and resolved tickets faster than the Claude models we use in production today. Tickets were processed 20% faster, getting our customers the help they need without the wait.”
Abhinay Kathuria·
Source text block 30 · customer quotation (opens in a new tab)
Coding task quality

Epic reports higher-tier quality on engineering tasks

Original excerpt

“In Epic’s early testing, Claude Sonnet 5.5 cleared the same quality bar you’d expect from a higher-tier model, holding up on a system design audit and a data flow review. The new model managed tens of thousands of lines of code for gameplay system architecture, kept responses snappy, handled multi-hour tasks, and delivered with less prescriptive prompting.”
Daniel Vogel·

Mentioned here

All mentioned things

Claude Sonnet 5.5

Supports

Gabriel Grinberg of Base44 reports that Claude Sonnet 5.5 matched Opus 5’s scores across 118 app builds, achieving them in fewer iterations (3.6 vs. 7.7) and with fewer failed tool calls and mid-build interruptions.

Read supporting evidence · Gabriel Grinberg
Supports

Daniel Vogel of Epic Games reports that Claude Sonnet 5.5 met the quality bar expected from a higher-tier model in early system-design and data-flow reviews, while handling long engineering tasks with less prescriptive prompting.

Read supporting evidence · Daniel Vogel
Supports

Curtis Allen of Slack reports that Claude Sonnet 5.5 outperformed Sonnet 5 on most offline Slackbot evaluations without prompt changes, using fewer steps and about 14% fewer output tokens.

Read supporting evidence · Curtis Allen
Supports

Abhinay Kathuria of Zendesk reports that Claude Sonnet 5.5 made fewer wrong decisions on hundreds of support use cases and processed tickets 20% faster than Zendesk’s previously deployed Claude models.

Read supporting evidence · Abhinay Kathuria

Source & methodology

These viewpoints are linked to their original sources. Paraphrases are labeled and are not verbatim quotes.

Open transcript or source material (opens in a new tab)Report an issue

Explore these viewpoints by person