fasthttp

Fast HTTP implementation for Go.

fasthttp might not be for you!

fasthttp was designed for some high performance edge cases. Unless your server/client needs to handle thousands of small to medium requests per second and needs a consistent low millisecond response time fasthttp might not be for you. For most cases net/http is much better as it's easier to use and can handle more cases. For most cases you won't even notice the performance difference.

General info and links

Currently fasthttp is successfully used by VertaMedia in a production serving up to 200K rps from more than 1.5M concurrent keep-alive connections per physical server.

TechEmpower Benchmark round 23 results

Server Benchmarks

Client Benchmarks

Install

Documentation

Examples from docs

Code examples

Awesome fasthttp tools

Switching from net/http to fasthttp

Fasthttp best practices

Related projects

FAQ

HTTP server performance comparison with net/http

In short, fasthttp server is up to 6 times faster than net/http. Below are benchmark results.

GOMAXPROCS=1

net/http server:

$ GOMAXPROCS=1 go test -bench=NetHTTPServerGet -benchmem -benchtime=10s
cpu: Intel(R) Xeon(R) CPU @ 2.20GHz
BenchmarkNetHTTPServerGet1ReqPerConn                      722565             15327 ns/op            3258 B/op         36 allocs/op
BenchmarkNetHTTPServerGet2ReqPerConn                      990067             11533 ns/op            2817 B/op         28 allocs/op
BenchmarkNetHTTPServerGet10ReqPerConn                    1376821              8734 ns/op            2483 B/op         23 allocs/op
BenchmarkNetHTTPServerGet10KReqPerConn                   1691265              7151 ns/op            2385 B/op         21 allocs/op
BenchmarkNetHTTPServerGet1ReqPerConn10KClients            643940             17152 ns/op            3529 B/op         36 allocs/op
BenchmarkNetHTTPServerGet2ReqPerConn10KClients            868576             14010 ns/op            2826 B/op         28 allocs/op
BenchmarkNetHTTPServerGet10ReqPerConn10KClients          1297398              9329 ns/op            2611 B/op         23 allocs/op
BenchmarkNetHTTPServerGet100ReqPerConn10KClients         1467963              7902 ns/op            2450 B/op         21 allocs/op

fasthttp server:

$ GOMAXPROCS=1 go test -bench=kServerGet -benchmem -benchtime=10s
cpu: Intel(R) Xeon(R) CPU @ 2.20GHz
BenchmarkServerGet1ReqPerConn                    4304683              2733 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet2ReqPerConn                    5685157              2140 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet10ReqPerConn                   7659729              1550 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet10KReqPerConn                  8580660              1422 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet1ReqPerConn10KClients          4092148              3009 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet2ReqPerConn10KClients          5272755              2208 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet10ReqPerConn10KClients         7566351              1546 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet100ReqPerConn10KClients        8369295              1418 ns/op               0 B/op          0 allocs/op

GOMAXPROCS=4

net/http server:

$ GOMAXPROCS=4 go test -bench=NetHTTPServerGet -benchmem -benchtime=10s
cpu: Intel(R) Xeon(R) CPU @ 2.20GHz
BenchmarkNetHTTPServerGet1ReqPerConn-4                   2670654              4542 ns/op            3263 B/op         36 allocs/op
BenchmarkNetHTTPServerGet2ReqPerConn-4                   3376021              3559 ns/op            2823 B/op         28 allocs/op
BenchmarkNetHTTPServerGet10ReqPerConn-4                  4387959              2707 ns/op            2489 B/op         23 allocs/op
BenchmarkNetHTTPServerGet10KReqPerConn-4                 5412049              2179 ns/op            2386 B/op         21 allocs/op
BenchmarkNetHTTPServerGet1ReqPerConn10KClients-4         2226048              5216 ns/op            3289 B/op         36 allocs/op
BenchmarkNetHTTPServerGet2ReqPerConn10KClients-4         2989957              3982 ns/op            2839 B/op         28 allocs/op
BenchmarkNetHTTPServerGet10ReqPerConn10KClients-4        4383570              2834 ns/op            2514 B/op         23 allocs/op
BenchmarkNetHTTPServerGet100ReqPerConn10KClients-4       5315100              2394 ns/op            2419 B/op         21 allocs/op

fasthttp server:

$ GOMAXPROCS=4 go test -bench=kServerGet -benchmem -benchtime=10s
cpu: Intel(R) Xeon(R) CPU @ 2.20GHz
BenchmarkServerGet1ReqPerConn-4                  7797037              1494 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet2ReqPerConn-4                 13004892               963.7 ns/op             0 B/op          0 allocs/op
BenchmarkServerGet10ReqPerConn-4                22479348               522.6 ns/op             0 B/op          0 allocs/op
BenchmarkServerGet10KReqPerConn-4               25899390               451.4 ns/op             0 B/op          0 allocs/op
BenchmarkServerGet1ReqPerConn10KClients-4        8421531              1469 ns/op               0 B/op          0 allocs/op
BenchmarkServerGet2ReqPerConn10KClients-4       13426772               903.7 ns/op             0 B/op          0 allocs/op
BenchmarkServerGet10ReqPerConn10KClients-4      21899584               513.5 ns/op             0 B/op          0 allocs/op
BenchmarkServerGet100ReqPerConn10KClients-4     25291686               439.4 ns/op             0 B/op          0 allocs/op

HTTP client comparison with net/http

In short, fasthttp client is up to 4 times faster than net/http. Below are benchmark results.

GOMAXPROCS=1

net/http client:

$ GOMAXPROCS=1 go test -bench='HTTPClient(Do|GetEndToEnd)' -benchmem -benchtime=10s
cpu: Intel(R) Xeon(R) CPU @ 2.20GHz
BenchmarkNetHTTPClientDoFastServer                        885637             13883 ns/op            3384 B/op         44 allocs/op
BenchmarkNetHTTPClientGetEndToEnd1TCP                     203875             55619 ns/op            6296 B/op         70 allocs/op
BenchmarkNetHTTPClientGetEndToEnd10TCP                    231290             54618 ns/op            6299 B/op         70 allocs/op
BenchmarkNetHTTPClientGetEndToEnd100TCP                   202879             58278 ns/op            6304 B/op         69 allocs/op
BenchmarkNetHTTPClientGetEndToEnd1Inmemory                396764             26878 ns/op            6216 B/op         69 allocs/op
BenchmarkNetHTTPClientGetEndToEnd10Inmemory               396422             28373 ns/op            6209 B/op         68 allocs/op
BenchmarkNetHTTPClientGetEndToEnd100Inmemory              363976             33101 ns/op            6326 B/op         68 allocs/op
BenchmarkNetHTTPClientGetEndToEnd1000Inmemory             208881             51725 ns/op            8298 B/op         84 allocs/op
BenchmarkNetHTTPClientGetEndToEndWaitConn1Inmemory           237          50451765 ns/op            7474 B/op         79 allocs/op
BenchmarkNetHTTPClientGetEndToEndWaitConn10Inmemory          237          50447244 ns/op            7434 B/op         77 allocs/op
BenchmarkNetHTTPClientGetEndToEndWaitConn100Inmemory         238          50067993 ns/op            8639 B/op         82 allocs/op
BenchmarkNetHTTPClientGetEndToEndWaitConn1000Inmemory       1366           7324990 ns/op            4064 B/op         44 allocs/op

fasthttp client:

$ GOMAXPROCS=1 go test -bench='kClient(Do|GetEndToEnd)' -benchmem -benchtime=10s
cpu: Intel(R) Xeon(R) CPU @ 2.20GHz
BenchmarkClientGetEndToEnd1TCP                    406376             26558 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd10TCP                   517425             23595 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd100TCP                  474800             25153 ns/op               3 B/op          0 allocs/op
BenchmarkClientGetEndToEnd1Inmemory              2563800              4827 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd10Inmemory             2460135              4805 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd100Inmemory            2520543              4846 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd1000Inmemory           2437015              4914 ns/op               2 B/op          0 allocs/op
BenchmarkClientGetEndToEnd10KInmemory            2481050              5049 ns/op               9 B/op          0 allocs/op

GOMAXPROCS=4

net/http client:

$ GOMAXPROCS=4 go test -bench='HTTPClient(Do|GetEndToEnd)' -benchmem -benchtime=10s
cpu: Intel(R) Xeon(R) CPU @ 2.20GHz
BenchmarkNetHTTPClientGetEndToEnd1TCP-4                           767133             16175 ns/op            6304 B/op         69 allocs/op
BenchmarkNetHTTPClientGetEndToEnd10TCP-4                          785198             15276 ns/op            6295 B/op         69 allocs/op
BenchmarkNetHTTPClientGetEndToEnd100TCP-4                         780464             15605 ns/op            6305 B/op         69 allocs/op
BenchmarkNetHTTPClientGetEndToEnd1Inmemory-4                     1356932              8772 ns/op            6220 B/op         68 allocs/op
BenchmarkNetHTTPClientGetEndToEnd10Inmemory-4                    1379245              8726 ns/op            6213 B/op         68 allocs/op
BenchmarkNetHTTPClientGetEndToEnd100Inmemory-4                   1119213             10294 ns/op            6418 B/op         68 allocs/op
BenchmarkNetHTTPClientGetEndToEnd1000Inmemory-4                   504194             31010 ns/op           17668 B/op        102 allocs/op

fasthttp client:

$ GOMAXPROCS=4 go test -bench='kClient(Do|GetEndToEnd)' -benchmem -benchtime=10s
cpu: Intel(R) Xeon(R) CPU @ 2.20GHz
BenchmarkClientGetEndToEnd1TCP-4                         1474552              8143 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd10TCP-4                        1710270              7186 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd100TCP-4                       1701672              6892 ns/op               4 B/op          0 allocs/op
BenchmarkClientGetEndToEnd1Inmemory-4                    6797713              1590 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd10Inmemory-4                   6663642              1782 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd100Inmemory-4                  6608209              1867 ns/op               0 B/op          0 allocs/op
BenchmarkClientGetEndToEnd1000Inmemory-4                 6254452              2645 ns/op               8 B/op          0 allocs/op
BenchmarkClientGetEndToEnd10KInmemory-4                  6944584              1966 ns/op              17 B/op          0 allocs/op

Install

go get -u github.com/valyala/fasthttp

Switching from net/http to fasthttp

Unfortunately, fasthttp doesn't provide API identical to net/http. See the FAQ for details. There is net/http -> fasthttp handler converter, but it is better to write fasthttp request handlers by hand in order to use all of the fasthttp advantages (especially high performance :) ).

Important points:

• Fasthttp works with RequestHandler functions instead of objects implementing Handler interface. Fortunately, it is easy to pass bound struct methods to fasthttp:

```go type MyHandler struct { foobar string }

// request handler in net/http style, i.e. method bound to MyHandler struct. func (h MyHandler) HandleFastHTTP(ctx fasthttp.RequestCtx) { // notice that we may access MyHandler properties here - see h.foobar. fmt.Fprintf(ctx, "Hello, world! Requested path is %q. Foobar is %q", ctx.Path(), h.foobar) }

// request handler in fasthttp style, i.e. just plain function. func fastHTTPHandler(ctx *fasthttp.RequestCtx) { fmt.Fprintf(ctx, "Hi there! RequestURI is %q", ctx.RequestURI()) }

// pass bound struct method to fasthttp myHandler := &MyHandler{ foobar: "foobar", } fasthttp.ListenAndServe(":8080", myHandler.HandleFastHTTP)

// pass plain function to fasthttp fasthttp.ListenAndServe(":8081", fastHTTPHandler) ```

• The RequestHandler accepts only one argument - RequestCtx. It contains all the functionality required for http request processing and response writing. Below is an example of a simple request handler conversion from net/http to fasthttp.

```go // net/http request handler requestHandler := func(w http.ResponseWriter, r *http.Request) { switch r.URL.Path { case "/foo": foo