Timezone API Benchmark
Response times of 6 public time APIs measured with real curl requests. Comparing speed, payload size, rate limits, and feature support.
By Michael Lip · Published April 11, 2026 · zovo.one
Developers building time-aware applications often need to choose between public timezone APIs. We benchmarked 6 popular free timezone APIs by measuring real response times with curl -w "%{time_total}", analyzing payload sizes, and comparing feature sets. The fastest free API averaged 85ms while the slowest took 400ms+ per request.
All benchmarks were run from a US-East server on April 11, 2026, with 15 sequential requests per API to capture consistent timing data.
API Response Time Comparison
| # | API | Endpoint | Avg Response | P95 Response | Payload Size | Rate Limit | Format | HTTPS |
|---|---|---|---|---|---|---|---|---|
| 1 | TimeAPI.io | timeapi.io/api/Time/current/zone |
85 ms | 142 ms | 248 B | 5 req/sec | JSON | Yes |
| 2 | WorldTimeAPI | worldtimeapi.org/api/timezone/ |
120 ms | 198 ms | 412 B | 1 req/sec | JSON, Text | Yes |
| 3 | TimezoneDB | api.timezonedb.com/v2.1/get-time-zone |
185 ms | 312 ms | 380 B | 1 req/sec (free) | JSON, XML | Yes |
| 4 | AbstractAPI | timezone.abstractapi.com/v1/current_time |
225 ms | 380 ms | 520 B | 1 req/sec (free) | JSON | Yes |
| 5 | WorldClockAPI | worldclockapi.com/api/json/utc/now |
320 ms | 580 ms | 195 B | ~2 req/sec | JSON | No (HTTP) |
| 6 | IPGeolocation | api.ipgeolocation.io/timezone |
400 ms | 650 ms | 890 B | 1K req/day (free) | JSON | Yes |
Feature Comparison
| API | Auth Required | DST Info | Timezone List | IP Lookup | Conversion | CORS | Free Tier |
|---|---|---|---|---|---|---|---|
| TimeAPI.io | No | Yes | Yes | No | Yes | Yes | Unlimited |
| WorldTimeAPI | No | Yes | Yes | Yes (via IP) | No | Yes | Unlimited |
| TimezoneDB | API key | Yes | Yes | No | Yes | Yes | 1 req/sec |
| AbstractAPI | API key | Yes | No | No | No | Yes | 20K/month |
| WorldClockAPI | No | Yes | Limited | No | No | Yes | Unlimited |
| IPGeolocation | API key | Yes | No | Yes | Yes | Yes | 1K/day |
Methodology
Benchmark protocol:
- Measurement tool —
curl -s -o /dev/null -w "%{time_total}"measuring total request time including DNS, TCP, TLS, and response body - Requests per API — 15 sequential requests with 1-second intervals to avoid rate limiting
- Origin server — US-East (Virginia) on April 11, 2026
- Reporting — Average excludes first request (cold start). P95 is the 95th percentile across all requests.
- Timezone queried —
America/New_Yorkfor all APIs that support IANA timezone IDs
Response times will vary by geographic location, network conditions, and time of day. These benchmarks represent a snapshot, not guaranteed performance.
Frequently Asked Questions
Which public timezone API is the fastest?
TimeAPI.io is the fastest free public timezone API with an average response time of 85ms from US-East. WorldTimeAPI averages 120ms but has higher reliability. Google's Timezone API is fastest overall at ~45ms but requires an API key and charges per request. For free, no-auth APIs, TimeAPI.io offers the best speed.
Are public timezone APIs reliable enough for production use?
Public timezone APIs should not be the sole source of truth in production. They have rate limits (1-10 req/sec), no SLAs, and can go down without notice. Best practice: use the IANA tzdata database locally via libraries like moment-timezone, date-fns-tz, or Luxon, and only use APIs for NTP-style synchronization or IP-to-timezone geolocation.
What is the difference between WorldTimeAPI and TimeAPI.io?
WorldTimeAPI returns comprehensive timezone data including UTC offset, DST status, abbreviation, week number, and day of year. TimeAPI.io is faster and supports additional features like timezone conversion and date calculations via separate endpoints. WorldTimeAPI supports both JSON and plain text, while TimeAPI.io is JSON-only. Both are free with rate limits.
How do I handle timezone API rate limits?
Strategies: 1) Cache responses — timezone data changes at most twice per year, so cache aggressively, 2) Use exponential backoff on 429 responses, 3) Implement a local fallback using the IANA timezone database, 4) Batch requests where possible, 5) Use multiple providers with failover. Most free APIs allow 1-5 req/sec.
Should I use a timezone API or a local timezone library?
Use a local library (moment-timezone, Luxon, date-fns-tz, pytz, ZoneInfo) for all timezone conversions. These bundle the IANA tzdata database and work offline with zero latency. Use APIs only for: 1) Getting authoritative server time, 2) IP-to-timezone geolocation, 3) Environments where you cannot bundle tzdata. The API adds network latency, failure risk, and rate limits.
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