What coding agents pick by default.
One default per developer-tool category, measured from real agent sessions: we ask the way developers ask, hundreds of times per category in different words, and record which tool the agent makes its primary pick. Winners are named; the full per-vendor funnels stay private.
| category | agent default | top-pick share |
|---|---|---|
| backend / BaaS | Supabase | 96% n=162, 95% CI 92-98 |
| feature flags | LaunchDarkly | 49% n=144, 95% CI 41-57 |
| transactional email | Resend | 52% n=162, 95% CI 44-59 |
| auth | Clerk | 35% n=243, 95% CI 29-41 |
| hosting | Vercel | 47% n=243, 95% CI 40-53 |
| voice AI | Vapi | 43% n=243, 95% CI 37-49 |
file uploads and AI integration are tracked but still accruing runs; they join the index once they clear the reporting bar.
Which backend do AI coding agents pick?
As of 2026 Q2, Supabase is the default backend pick of AI coding agents: the top pick in 96% of 162 recommendation probes (95% CI 92-98; exploratory release).
The most concentrated category we measure. When an agent hears “I need a backend,” the selection is effectively already decided.
Which feature-flag platform do AI coding agents pick?
As of 2026 Q2, LaunchDarkly is the default feature-flag pick of AI coding agents: the top pick in 49% of 144 recommendation probes (95% CI 41-57; exploratory release).
Which email API do AI coding agents pick?
As of 2026 Q2, Resend is the default transactional-email pick of AI coding agents: the top pick in 52% of 162 recommendation probes (95% CI 44-59; exploratory release).
Raw Nodemailer or SMTP appears in 42% of email answers, so the strongest rival here is no vendor at all.
Which auth provider do AI coding agents pick?
As of 2026 Q2, Clerk is the default auth pick of AI coding agents: the top pick in 35% of 243 recommendation probes (95% CI 29-41; exploratory release).
An auth library like NextAuth or Lucia is named in 62% of auth answers. DIY is the real runner-up.
Where do AI coding agents deploy?
As of 2026 Q2, Vercel is the default hosting pick of AI coding agents: the top pick in 47% of 243 recommendation probes (95% CI 40-53; exploratory release).
Self-hosting comes up in 19% of hosting answers.
Which voice-AI platform do AI coding agents pick?
As of 2026 Q2, Vapi is the default voice-AI pick of AI coding agents: the top pick in 43% of 243 recommendation probes (95% CI 37-49; exploratory release).
How to read this index.
Top-pick share
How often the agent makes this tool its primary pick when asked to build in the category. Being named isn't being picked; plenty of tools are mentioned constantly and chosen never.
Release status
Reportable results from an exploratory, not-yet-citable release, shown with sample size and interval. Below n=30 a cell is underpowered and excluded.
Agents covered
Claude Code and Codex, across multiple wordings of each task. Per-model splits and full funnels live in the private scorecards.
Full method, detection, and gates: the methodology. The findings behind the index: the Agent Default Report.
The index is the public average. Your funnel is the product.
Edition 2026 Q2 · updated July 2026. Correction (July 8): shares re-derived from the canonical primary-pick count; the auth and feature-flag figures in the first cut were overstated. Winners unchanged.