Skip to content
This repository has been archived by the owner on Sep 14, 2021. It is now read-only.


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time

🚨 Note: this repo has been archived and its contents are now in the sourcegraph/sourcegraph repo.

Syntect Server

This is an HTTP server that exposes the Rust Syntect syntax highlighting library for use by other services. Send it some code, and it'll send you syntax-highlighted code in response.


  • Syntect -> Syntax highlighting of code.
  • -> Web framework.
  • Serde -> JSON serialization / deserialization .
  • Rayon -> data parallelism for SyntaxSet across Rocket server threads.
  • lazy_static -> lazily evaluated static ThemeSet (like a global).


docker run --detach --name=syntect_server -p 9238:9238 sourcegraph/syntect_server

You can then e.g. GET http://localhost:9238/health or http://host.docker.internal:9238/health to confirm it is working.


  • POST to / with Content-Type: application/json. The following fields are required:
    • filepath string, e.g. the/file.go or file.go or Dockerfile, see "Supported file extensions" section below.
    • theme string, e.g. Solarized (dark), see "Embedded themes" section below.
    • code string, i.e. the literal code to highlight.
  • The response is a JSON object of either:
    • A successful response (data field):
      • data string with syntax highlighted response. The input code string is properly escaped and as such can be directly rendered in the browser safely.
      • plaintext boolean indicating whether a syntax could not be found for the file and instead it was rendered as plain text.
    • An error response (error field), one of:
      • {"error": "invalid theme", "code": "invalid_theme"}
      • {"error": "resource not found", "code": "resource_not_found"}
  • GET to /health to receive an OK health check response / ensure the service is alive.


gosyntect is a Go package + CLI program to make requests against syntect_server.


By default on startup, syntect_server will list all features (themes + file types) it supports. This can be disabled by setting QUIET=true in the environment.


  1. Install Rust nightly.
  2. git clone this repository anywhere on your filesystem.
  3. Use cargo run to download dependencies + compile + run the server.


Invoke cargo build --release and an optimized binary will be built (e.g. to ./target/release/syntect_server).

Building docker image

./ will build your current repository checkout into a final Docker image.

Publishing docker image

Run ./ after merging your changes.

Updating Sourcegraph

Once published, the image version will need to be updated in the following locations to make Sourcegraph use it:

Additionally, it's worth doing a search for other uses in case this list is stale.

Code hygiene

  • Use cargo fmt or an editor extension to format code.

Adding themes

  • Copy a .tmTheme file anywhere under ./syntect/testdata (make a new dir if needed) in our fork.
  • cd syntect && make assets
  • In this repo, cargo update -p syntect.
  • Build a new binary.

Adding languages:

1) Find an open-source .tmLanguage or .sublime-syntax file and send a PR to our package registry is the package registry we use which holds all of the syntax definitions we use in syntect_server and Sourcegraph. Send a PR there by following these steps

2) Update our temporary fork of syntect

We use a temporary fork of syntect as a hack to get our Packages registry into the binary. Update it by creating a PR with two commits like:

3) Update syntect_server to use the new version of syntect

Send a PR to this repository with the result of running cargo update -p syntect.

4) Publish a new image, use it in Sourcegraph

Run ./ to build and release a new image of syntect_server, and then send a PR to the main Sourcegraph repository like this. Once merged, it will automatically rollout to and go in the next Sourcegraph release.

Embedded themes:

  • InspiredGitHub
  • Monokai
  • Solarized (dark)
  • Solarized (light)
  • Sourcegraph
  • Sourcegraph (light)
  • TypeScript
  • TypeScriptReact
  • Visual Studio
  • Visual Studio Dark
  • base16-eighties.dark
  • base16-mocha.dark
  • base16-ocean.dark
  • base16-ocean.light

Supported file extensions:

  • Plain Text (txt)
  • ASP (asa)
  • HTML (ASP) (asp)
  • ASP vb.NET (vb)
  • HTML ( (aspx, ascx, master)
  • ActionScript (as)
  • AppleScript (applescript, script editor)
  • Batch File (bat, cmd)
  • NAnt Build File (build)
  • C# (cs, csx)
  • C++ (cpp, cc, cp, cxx, c++, C, h, hh, hpp, hxx, h++, inl, ipp)
  • C (c, h)
  • CMake Cache (CMakeCache.txt)
  • CMake Listfile (CMakeLists.txt, cmake)
  • ACUCOBOL (``)
  • COBOL (cbl, cpy, cob, dds, ss, wks, pco)
  • OpenCOBOL (``)
  • jcl (jcl)
  • CSS (css, css.erb, css.liquid)
  • Cap’n Proto (capnp)
  • Cg (cg)
  • Clojure (clj, cljc, cljs, cljx, edn)
  • Coq (v)
  • Crontab (crontab)
  • CUDA C++ (cu, cuh)
  • D (d, di)
  • DMD Output (``)
  • Dart Doc Comments (``)
  • Dart (dart)
  • Diff (diff, patch)
  • Dockerfile (Dockerfile)
  • DM (dm, dme)
  • Elixir (EEx) (ex.eex, exs.eex)
  • Elixir (ex, exs)
  • HTML (EEx) (html.eex, html.leex)
  • Regular Expressions (Elixir) (
  • SQL (Elixir) (ex.sql)
  • Elm (elm)
  • Erlang (erl, hrl, Emakefile, emakefile, escript)
  • HTML (Erlang) (yaws)
  • Solidity (sol)
  • Vyper (vy)
  • F Sharp (fs)
  • friendly interactive shell (fish) (fish)
  • Forth (frt, fs)
  • ESSL (essl, f.essl, v.essl, _v.essl, _f.essl, _vs.essl, _fs.essl)
  • GLSL (vs, fs, gs, vsh, fsh, gsh, vshader, fshader, gshader, vert, frag, geom, tesc, tese, comp, glsl)
  • Git Attributes (attributes, gitattributes, .gitattributes)
  • Git Common (``)
  • Git Config (gitconfig, .gitconfig, .gitmodules)
  • Git Ignore (exclude, gitignore, .gitignore)
  • Git Link (.git)
  • Git Log (gitlog)
  • Git Mailmap (.mailmap, mailmap)
  • Git Rebase Todo (git-rebase-todo)
  • Go (go)
  • GraphQL (graphql, graphqls, gql, graphcool)
  • Graphviz (DOT) (dot, DOT, gv)
  • Groovy (groovy, gvy, gradle, Jenkinsfile)
  • HLSL (fx, fxh, hlsl, hlsli, usf)
  • HTML (html, htm, shtml, xhtml)
  • Haskell (hs)
  • Literate Haskell (lhs)
  • INI (cfg, conf, ini, lng, url, .buckconfig, .flowconfig, .hgrc)
  • REG (reg)
  • JSON (json, sublime-settings, sublime-menu, sublime-keymap, sublime-mousemap, sublime-theme, sublime-build, sublime-project, sublime-completions, sublime-commands, sublime-macro, sublime-color-scheme, ipynb, Pipfile.lock)
  • Java Server Page (JSP) (jsp)
  • Java (java, bsh)
  • Javadoc (``)
  • Java Properties (properties)
  • JS Custom - Default (js, htc)
  • JS Custom - React (js, jsx)
  • Regular Expressions (Javascript) (``)
  • JS Custom (Embedded) (``)
  • Julia (jl)
  • Kotlin (kt, kts)
  • LESS (less)
  • BibTeX (bib)
  • LaTeX Log (``)
  • LaTeX (tex, ltx)
  • TeX (sty, cls)
  • Lisp (lisp, cl, clisp, l, mud, el, scm, ss, lsp, fasl)
  • Lua (lua)
  • MSBuild (proj, targets, msbuild, csproj, vbproj, fsproj, vcxproj)
  • Make Output (``)
  • Makefile (make, GNUmakefile, makefile, Makefile,,,,, OCamlMakefile, mak, mk)
  • Man (man)
  • Markdown (md, mdown, markdown, markdn)
  • MultiMarkdown (``)
  • MATLAB (matlab)
  • Maven POM (pom.xml)
  • Mediawiki (mediawiki, wikipedia, wiki)
  • Move (move)
  • Ninja (ninja)
  • Nix (nix)
  • OCaml (ml, mli)
  • OCamllex (mll)
  • OCamlyacc (mly)
  • camlp4 (``)
  • Objective-C++ (mm, M, h)
  • Objective-C (m, h)
  • PHP Source (``)
  • PHP (php, php3, php4, php5, php7, phps, phpt, phtml)
  • Regular Expressions (PHP) (``)
  • Pascal (pas, p, dpr)
  • Perl (pl, pc, pm, pmc, pod, t)
  • Property List (XML) (``)
  • Postscript (ps, eps)
  • PowerShell (ps1, psm1, psd1)
  • Protocol Buffer (proto)
  • Puppet (pp, epp)
  • Python (py, py3, pyw, pyi, pyx,, pxd,, pxi,, rpy, cpy, SConstruct, Sconstruct, sconstruct, SConscript, pyst, pyst-include, gyp, gypi, Snakefile, vpy, wscript, bazel, bzl)
  • Regular Expressions (Python) (``)
  • R Console (``)
  • R (R, r, Rprofile)
  • Rd (R Documentation) (rd)
  • HTML (Rails) (rails, rhtml, erb, html.erb)
  • JavaScript (Rails) (js.erb)
  • Ruby Haml (haml)
  • Ruby on Rails (rxml, builder)
  • SQL (Rails) (erbsql, sql.erb)
  • Regular Expression (re)
  • reStructuredText (rst, rest)
  • Ruby (rb, Appfile, Appraisals, Berksfile, Brewfile, capfile, cgi, Cheffile,, Deliverfile, Fastfile, fcgi, Gemfile, gemspec, Guardfile, irbrc, jbuilder, Podfile, podspec, prawn, rabl, rake, Rakefile, Rantfile, rbx, rjs, ruby.rail, Scanfile, simplecov, Snapfile, thor, Thorfile, Vagrantfile)
  • Cargo Build Results (``)
  • Rust Enhanced (rs)
  • Sass (sass, scss)
  • SQL (sql, ddl, dml)
  • Scala (scala, sbt, sc)
  • Bourne Again Shell (bash) (sh, bash, zsh, ash, .bash_aliases, .bash_completions, .bash_functions, .bash_login, .bash_logout, .bash_profile, .bash_variables, .bashrc, .profile, .textmate_init, .zlogin, .zlogout, .zprofile, .zshenv, .zshrc, PKGBUILD, .ebuild, .eclass)
  • Shell-Unix-Generic (``)
  • commands-builtin-shell-bash (``)
  • Smalltalk (st)
  • Smarty (tpl)
  • Starlark (build_defs,, BUILD, WORKSPACE, bzl, sky, star, BUILD.bazel, WORKSPACE, WORKSPACE.bazel)
  • Stylus (styl, stylus)
  • Swift (swift)
  • HTML (Tcl) (adp)
  • Tcl (tcl)
  • TOML (toml)
  • Terraform (tf, tfvars, hcl)
  • Textile (textile)
  • Thrift (thrift, frugal)
  • TypeScript (ts)
  • TypeScriptReact (tsx)
  • VimL (vim, .vimrc, .gvimrc)
  • Vue Component (vue)
  • XML (xml, xsd, xslt, tld, dtml, rng, rss, opml, svg)
  • YAML (yaml, yml, sublime-syntax)
  • Zig (zig)