Add configurable rate limit option

[sethconvex]

Summary

• Allow users to configure a custom rate limit via the new rateLimitMs option
• Default remains 600ms (uses existing rate limiter for most users)
• Custom rates use timestamp-based rate limiting for accounts with higher limits approved by Resend

Test plan

• All existing tests pass (27/27)
• Build succeeds
• Lint passes with no warnings
• Manual testing with default rate limit (should use existing rate limiter)
• Manual testing with custom rate limit (should use timestamp-based limiting)

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features
  • Added an optional rateLimitMs parameter to allow customizing API call rate limits.
  • Improved rate-limiting behavior to support both the default and custom rates for more flexible request throttling.

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[coderabbitai]

📝 Walkthrough

Walkthrough

A new runtime option rateLimitMs was added and threaded from ResendOptions through runtime config into the component rate-limiting logic; getDelay now supports default fixed-window behavior or a timestamp-based custom rate with jitter and last-call tracking.

Changes

Cohort / File(s)	Summary
Client & Public Types src/client/index.ts	Exposed optional rateLimitMs?: number on ResendOptions and wired it into runtime config conversion and the Resend constructor.
Runtime Options src/component/shared.ts	Added rateLimitMs to vOptions, updating the inferred RuntimeConfig to include the new numeric option.
Schema src/component/schema.ts	Added lastApiCallTime: v.optional(v.number()) to the lastOptions table to store timestamp of the last API call for custom-rate logic.
Rate-limiting Logic src/component/lib.ts	getDelay(ctx, rateLimitMs) refactor: preserves default fixed-window limiter when using default rate, otherwise uses timestamp-based delay with jitter and reserves a slot by updating lastApiCallTime. Callers updated to pass rateLimitMs.
Tests / Test Config src/component/lib.test.ts, src/component/setup.test.ts	Added rateLimitMs: 600 to test option blocks and test runtime config to exercise custom-rate paths in tests.

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant Resend
  participant Component as "Component.makeBatch"
  participant Store as "lastOptions Store"
  participant API as "External API"

  Client->>Resend: sendEmail(options with rateLimitMs)
  Resend->>Component: makeBatch(options, runtimeConfig)
  Component->>Store: read lastApiCallTime (if custom rate)
  alt default rate (fixed-window)
    Component->>Component: use fixed-window rate limiter -> may delay
  else custom rate
    Component->>Component: compute elapsed, jitter, delay
    Component->>Store: update lastApiCallTime (reserve slot)
  end
  Component->>API: perform API call(s) after delay
  API-->>Component: response
  Component-->>Resend: result
  Resend-->>Client: deliver response

Loading

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Poem

🐰 I hopped through timestamps, jitter in tow,
A tiny delay makes the calls flow,
I nudged the clock, reserved a slot,
Faster or gentler—I've got the plot! 🎩✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Add configurable rate limit option' accurately and concisely summarizes the main change: introducing a new configurable rateLimitMs option. It aligns with all file changes and the PR objectives.

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✨ Finishing touches

• 📝 Generate docstrings

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[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/get-convex/resend/@convex-dev/resend@67

commit: eee2480

[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@src/component/lib.ts`:
- Around line 445-447: Guard against undefined rateLimitMs by defaulting
options.rateLimitMs (or lastOptions.options.rateLimitMs) to a safe number before
calling getDelay so it never receives undefined and returns NaN; also when
updating lastApiCallTime after computing delay, include the reserved jitter (the
same jitter used by getDelay) so the stored lastApiCallTime = now +
reservedDelay (delay including jitter) to avoid under‑reservation—update
references to getDelay(ctx, options.rateLimitMs), lastOptions.options, and
lastApiCallTime accordingly to apply the default and add the jitter when saving
the timestamp.