Migrating from Sonar to the Agent API isn’t a simple model-string swap; endpoint paths, request bodies, and response parsing all change, creating potential breaking changes for UI citations and source attributions.

A structured 15-minute triage is available, with an optional full migration kit that includes checklists, code prompts, testing plans, rollback guidance, and FAQs to address misstatements in vendor announcements and pricing.

Migration details and vendor timelines are drawn from Perplexity and Appsmith documentation, plus related GitHub pull requests cited in the article.

Appsmith AI datasources and queries are deprecated with a migration path to OpenAI, Anthropic, or Google AI datasources, and managed Appsmith credentials will be revoked after go-live.

Perplexity will retire the Sonar API on September 27, 2026, shifting the main surface to the Agent API, while Appsmith will shut down its managed AI plugin by the end of September 2026.

The Sonar 200K input window applies to sonar-pro, but the Agent API’s context window isn’t publicly specified, so Perplexity must confirm large-input planning in writing.

The Agent API introduces a new cost model and rate limits, with per-tool invocation fees (web_search, fetch_url, finance_search, people_search) and tier-based quotas, plus cumulative spend caps that could affect throughput.

Two migration traps to watch: uploaded file context may not transfer and recent Appsmith plugin changes can expose raw messages-API bodies instead of completion-shaped bodies, impacting widget bindings and JS objects.