diff --git a/cli/src/main.rs b/cli/src/main.rs
index e88c0e7..f78bb9b 100644
--- a/cli/src/main.rs
+++ b/cli/src/main.rs
@@ -40,7 +40,7 @@ impl Input {
 
 #[derive(Debug, Parser)]
 struct Args {
-    #[arg(long, default_value_t = fuk::output::Format::JSONPretty)]
+    #[arg(long, default_value_t = fuk::output::Format::JSON)]
     format: fuk::output::Format,
     /// File containing list of keys to be fetched
     #[arg(value_hint = clap::ValueHint::FilePath)]
@@ -54,7 +54,9 @@ fn main() -> Result<()> {
 
     let output = fuk::fuk(config);
 
-    println!("{}", args.format.render(&output));
+    let out = std::io::stdout();
+    let mut out = out.lock();
+    args.format.render(&output, &mut out)?;
 
     Ok(())
 }
diff --git a/cli/src/output/mod.rs b/cli/src/output/mod.rs
index 70ae75a..96daff6 100644
--- a/cli/src/output/mod.rs
+++ b/cli/src/output/mod.rs
@@ -3,22 +3,24 @@
 // SPDX-License-Identifier: EUPL-1.2
 
 use std::collections::HashMap;
+use std::io::{self, prelude::*};
 
 #[derive(PartialEq, Eq, Debug, Copy, Clone)]
 pub enum Format {
     JSON,
-    JSONPretty,
     TOML,
-    TOMLPretty,
+    CSV,
 }
 
 impl Format {
-    pub fn render(self, output: &Output) -> String {
+    pub fn render<W: Write>(self, output: &Output, w: &mut W) -> io::Result<()> {
         match self {
-            Format::JSON => serde_json::to_string(&output.keys).unwrap(),
-            Format::JSONPretty => serde_json::to_string_pretty(&output.keys).unwrap(),
-            Format::TOML => toml::to_string(&output.keys).unwrap(),
-            Format::TOMLPretty => toml::to_string_pretty(&output.keys).unwrap(),
+            Format::JSON => {
+                serde_json::to_writer_pretty(&mut *w, &output.keys).map_err(io::Error::other)?;
+                writeln!(w, "")
+            }
+            Format::TOML => write!(w, "{}", toml::to_string_pretty(&output.keys).unwrap()),
+            Format::CSV => as_csv(w, &output),
         }
     }
 }
@@ -27,9 +29,8 @@ impl std::fmt::Display for Format {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match *self {
             Format::JSON => f.write_str("json"),
-            Format::JSONPretty => f.write_str("json-pretty"),
             Format::TOML => f.write_str("toml"),
-            Format::TOMLPretty => f.write_str("toml-pretty"),
+            Format::CSV => f.write_str("csv"),
         }
     }
 }
@@ -38,10 +39,8 @@ impl<'a> From<&'a str> for Format {
     fn from(s: &'a str) -> Format {
         match s {
             "json" => Format::JSON,
-            "pretty" => Format::JSONPretty,
-            "json-pretty" => Format::JSONPretty,
             "toml" => Format::TOML,
-            "toml-pretty" => Format::TOMLPretty,
+            "csv" => Format::CSV,
             _ => unreachable!(),
         }
     }
@@ -51,3 +50,14 @@ impl<'a> From<&'a str> for Format {
 pub struct Output {
     pub keys: HashMap<String, Vec<ssh_key::PublicKey>>,
 }
+
+// TODO: proper escaping
+fn as_csv<W: Write>(w: &mut W, output: &Output) -> io::Result<()> {
+    for (name, keys) in &output.keys {
+        for key in keys {
+            writeln!(w, "{name},{}", key.to_string())?;
+        }
+    }
+
+    Ok(())
+}
diff --git a/docs/fuk.1.scd b/docs/fuk.1.scd
index ea1a878..d9998fb 100644
--- a/docs/fuk.1.scd
+++ b/docs/fuk.1.scd
@@ -7,7 +7,8 @@ fuk - Fetch User Keys
 # SYNOPSIS
 
 *fuk* -h++
-*fuk* [--format (json|json-pretty|toml|toml-pretty)] _config.toml_
+*fuk* --help++
+*fuk* [--format (json|toml|csv)] _config.toml_
 
 # DESCRIPTION
 
@@ -68,11 +69,13 @@ keys = [
 
 # OUTPUT
 
-_fuk_ prints result to stdout in JSON format. Keys will be deduplicated by
+_fuk_ prints result to stdout in selected format. Keys will be deduplicated by
 algorithm and key, but the comment *will* be ignored when comparing for
 equality. If comments for duplicated keys are different, then there is no
 guarantee about comment content.
 
+Possible formats - JSON, TOML, CSV.
+
 Example output:
 
 ```