Time To First Byte (TTFB) Checker
Measure server processing time—how long until the server starts responding. Isolate backend performance from network latency.
About Latency Test
Test network latency and round-trip time from 6 global probe locations. Measure connection latency, TCP handshake time, and network path efficiency.
Key Features
Multi-region latency testing
Time to First Byte (TTFB)
Connection time measurement
DNS lookup time
Historical comparison
Time To First Byte (TTFB) measures specifically how long the server takes to START sending a response after receiving a request. This isolates server-side processing time—database queries, application logic, caching—from network latency and data transfer. TTFB under 200ms is good; under 100ms is excellent.
Unlike full response time tests, TTFB focuses purely on backend performance. High TTFB with low network latency points to server optimization opportunities: slow database queries, missing cache layers, inefficient code, or undersized hosting. Our multi-region TTFB test reveals if backend slowness affects all users or varies by geography.
For complete performance diagnosis, compare TTFB results with network latency to separate network delays from server processing. Check DNS performance as slow DNS adds to total wait time before TTFB even starts.
**Methodology:** HTTP request with precise TTFB isolation from 6 regions, measuring time from request sent to first response byte received.
Common Errors & How to Fix Them
4 relevant issuesThe server responded but took too long. This affects user experience and may indicate server performance issues.
1) Identify bottleneck: check DNS time, connect time, TTFB separately. 2) If DNS slow: switch to faster DNS provider. 3) If TTFB slow: optimize server-side code, add caching, check database queries. 4) If transfer slow: enable compression (gzip), optimize assets. 5) Consider CDN for geographic distribution.
The gateway server didn't receive a timely response from the upstream server. The upstream server is too slow or unresponsive.
1) For site owners: increase timeout values (proxy_read_timeout in nginx). 2) Optimize slow backend code/queries. 3) Check database performance. 4) Add caching layers. 5) Test: curl -I -m 30 https://example.com to check response time.
The server is temporarily unable to handle the request due to maintenance or overload. Usually temporary.
1) For users: wait and retry—often means scheduled maintenance. 2) For site owners: check server resources (htop, free -m). 3) Scale up if overloaded. 4) Check if maintenance mode is accidentally enabled. 5) Review rate limiting settings.
The server didn't respond within the expected time. Could be server overload, network issues, or firewall blocking.
1) Check if server is reachable: ping example.com. 2) Test specific port: nc -vz example.com 443 -w 5. 3) Check from different location (VPN/proxy). 4) For owners: verify firewall allows traffic (ufw status), check server resources, ensure service is running.
Frequently Asked Questions
4 relevant questionsTTFB measures the time from when you request a page to when you receive the first byte of the response. It includes DNS lookup, TCP connection, SSL handshake, and server processing time. A good TTFB is under 200ms; acceptable is under 500ms. High TTFB usually indicates server-side issues like slow databases, inefficient code, or distant servers.
SSL handshakes can add 100-300ms. Speed it up by: enabling TLS 1.3 (faster handshake), using OCSP stapling (avoids certificate validation delays), enabling session resumption, using smaller certificate chains, and deploying on servers with modern CPU support for cryptographic operations.
Slow DNS can add 50-200ms to every request. Causes include: slow DNS provider, too many DNS lookups (external resources), and no DNS prefetching. Fix by: using fast DNS providers (Cloudflare 1.1.1.1, Google 8.8.8.8), reducing external resources, implementing DNS prefetching (<link rel="dns-prefetch">), and using longer TTLs.
Key strategies: 1) Use a CDN to serve content from edge locations, 2) Enable HTTP/2 or HTTP/3 for faster connections, 3) Optimize server response time with caching, 4) Reduce DNS lookup time by using fast DNS providers, 5) Enable keep-alive connections, 6) Minimize redirects, 7) Use connection preloading and prefetching.
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