diff --git a/Cargo.lock b/Cargo.lock
index 9fcd021f..95f5482d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -103,7 +103,7 @@ dependencies = [
  "futures-core",
  "futures-util",
  "mio",
- "socket2",
+ "socket2 0.5.5",
  "tokio",
  "tracing",
 ]
@@ -164,7 +164,7 @@ dependencies = [
  "serde_json",
  "serde_urlencoded",
  "smallvec",
- "socket2",
+ "socket2 0.5.5",
  "time",
  "url",
 ]
@@ -255,9 +255,9 @@ dependencies = [
 
 [[package]]
 name = "annonars"
-version = "0.24.2"
+version = "0.24.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "264ef5bcefef042e0c4e39fa5b6a30aebaceca9876917915974823a54668d426"
+checksum = "13c333725a9ab813623f9a9a2ccfdf7f957617f5197b55c469ec183a5b618f2e"
 dependencies = [
  "actix-web",
  "anyhow",
@@ -358,6 +358,131 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "async-attributes"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a3203e79f4dd9bdda415ed03cf14dae5a2bf775c683a00f94e9cd1faf0f596e5"
+dependencies = [
+ "quote",
+ "syn 1.0.109",
+]
+
+[[package]]
+name = "async-channel"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81953c529336010edd6d8e358f886d9581267795c61b19475b71314bffa46d35"
+dependencies = [
+ "concurrent-queue",
+ "event-listener",
+ "futures-core",
+]
+
+[[package]]
+name = "async-compression"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f658e2baef915ba0f26f1f7c42bfb8e12f532a01f449a090ded75ae7a07e9ba2"
+dependencies = [
+ "flate2",
+ "futures-core",
+ "memchr",
+ "pin-project-lite",
+ "tokio",
+]
+
+[[package]]
+name = "async-executor"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b0c4a4f319e45986f347ee47fef8bf5e81c9abc3f6f58dc2391439f30df65f0"
+dependencies = [
+ "async-lock",
+ "async-task",
+ "concurrent-queue",
+ "fastrand 2.0.1",
+ "futures-lite",
+ "slab",
+]
+
+[[package]]
+name = "async-global-executor"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1b6f5d7df27bd294849f8eec66ecfc63d11814df7a4f5d74168a2394467b776"
+dependencies = [
+ "async-channel",
+ "async-executor",
+ "async-io",
+ "async-lock",
+ "blocking",
+ "futures-lite",
+ "once_cell",
+]
+
+[[package]]
+name = "async-io"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fc5b45d93ef0529756f812ca52e44c221b35341892d3dcc34132ac02f3dd2af"
+dependencies = [
+ "async-lock",
+ "autocfg",
+ "cfg-if",
+ "concurrent-queue",
+ "futures-lite",
+ "log",
+ "parking",
+ "polling",
+ "rustix 0.37.26",
+ "slab",
+ "socket2 0.4.10",
+ "waker-fn",
+]
+
+[[package]]
+name = "async-lock"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "287272293e9d8c41773cec55e365490fe034813a2f172f502d6ddcf75b2f582b"
+dependencies = [
+ "event-listener",
+]
+
+[[package]]
+name = "async-std"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62565bb4402e926b29953c785397c6dc0391b7b446e45008b0049eb43cec6f5d"
+dependencies = [
+ "async-attributes",
+ "async-channel",
+ "async-global-executor",
+ "async-io",
+ "async-lock",
+ "crossbeam-utils",
+ "futures-channel",
+ "futures-core",
+ "futures-io",
+ "futures-lite",
+ "gloo-timers",
+ "kv-log-macro",
+ "log",
+ "memchr",
+ "once_cell",
+ "pin-project-lite",
+ "pin-utils",
+ "slab",
+ "wasm-bindgen-futures",
+]
+
+[[package]]
+name = "async-task"
+version = "4.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4eb2cdb97421e01129ccb49169d8279ed21e829929144f4a22a6e54ac549ca1"
+
 [[package]]
 name = "async-trait"
 version = "0.1.74"
@@ -369,6 +494,12 @@ dependencies = [
  "syn 2.0.38",
 ]
 
+[[package]]
+name = "atomic-waker"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -538,6 +669,22 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "blocking"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8c36a4d0d48574b3dd360b4b7d95cc651d2b6557b6402848a27d4b228a473e2a"
+dependencies = [
+ "async-channel",
+ "async-lock",
+ "async-task",
+ "fastrand 2.0.1",
+ "futures-io",
+ "futures-lite",
+ "piper",
+ "tracing",
+]
+
 [[package]]
 name = "boolvec"
 version = "0.2.6"
@@ -742,6 +889,15 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
 
+[[package]]
+name = "concurrent-queue"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f057a694a54f12365049b0958a1685bb52d567f5593b355fbf685838e873d400"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "console"
 version = "0.15.7"
@@ -1070,6 +1226,12 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "event-listener"
+version = "2.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0206175f82b8d6bf6652ff7d71a1e27fd2e4efde587fd368662814d6ec1d9ce0"
+
 [[package]]
 name = "fallible-iterator"
 version = "0.2.0"
@@ -1082,6 +1244,15 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7360491ce676a36bf9bb3c56c1aa791658183a54d2744120f27285738d90465a"
 
+[[package]]
+name = "fastrand"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e51093e27b0797c359783294ca4f0a911c270184cb10f85783b118614a1501be"
+dependencies = [
+ "instant",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.0.1"
@@ -1179,6 +1350,21 @@ version = "0.3.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4fff74096e71ed47f8e023204cfd0aa1289cd54ae5430a9523be060cdb849964"
 
+[[package]]
+name = "futures-lite"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49a9d51ce47660b1e808d3c990b4709f2f415d928835a17dfd16991515c46bce"
+dependencies = [
+ "fastrand 1.9.0",
+ "futures-core",
+ "futures-io",
+ "memchr",
+ "parking",
+ "pin-project-lite",
+ "waker-fn",
+]
+
 [[package]]
 name = "futures-macro"
 version = "0.3.28"
@@ -1280,6 +1466,18 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
 
+[[package]]
+name = "gloo-timers"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b995a66bb87bebce9a0f4a95aed01daca4872c050bfcb21653361c03bc35e5c"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "h2"
 version = "0.3.21"
@@ -1589,6 +1787,15 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "kv-log-macro"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0de8b303297635ad57c9f5059fd9cee7a47f8e8daa09df0fcd07dd39fb22977f"
+dependencies = [
+ "log",
+]
+
 [[package]]
 name = "language-tags"
 version = "0.3.2"
@@ -1678,6 +1885,12 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f051f77a7c8e6957c0696eac88f26b0117e54f52d3fc682ab19397a8812846a4"
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef53942eb7bf7ff43a617b3e2c1c4a5ecf5944a7c1bc12d7ee39bbb15e5c1519"
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.4.10"
@@ -1716,6 +1929,9 @@ name = "log"
 version = "0.4.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5e6163cb8c49088c2c36f57875e58ccd8c87c7427f7fbd50ea6710b2f3f2e8f"
+dependencies = [
+ "value-bag",
+]
 
 [[package]]
 name = "lz4-sys"
@@ -1754,6 +1970,8 @@ dependencies = [
  "actix-web",
  "annonars",
  "anyhow",
+ "async-compression",
+ "async-std",
  "bgzip",
  "bio",
  "biocommons-bioutils",
@@ -1766,6 +1984,7 @@ dependencies = [
  "derivative",
  "env_logger",
  "flate2",
+ "futures",
  "hgvs",
  "indexmap 2.0.2",
  "indicatif",
@@ -1799,6 +2018,7 @@ dependencies = [
  "temp_testdir",
  "tempfile",
  "thousands",
+ "tokio",
  "tracing",
  "tracing-subscriber",
  "uuid",
@@ -1954,6 +2174,10 @@ dependencies = [
  "bytes",
  "crossbeam-channel",
  "flate2",
+ "futures",
+ "pin-project-lite",
+ "tokio",
+ "tokio-util",
 ]
 
 [[package]]
@@ -2001,23 +2225,25 @@ dependencies = [
 
 [[package]]
 name = "noodles-tabix"
-version = "0.30.0"
+version = "0.31.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f69786c5eaa25460ae5ea61215f8869edd7eb1728c043f314420cea0bbe59ed3"
+checksum = "d12d6981ba752798cb03abc9604324ff6cbc1e5354252f95c372545d967a6daf"
 dependencies = [
  "bit-vec",
  "byteorder",
  "noodles-bgzf 0.25.0",
  "noodles-core",
  "noodles-csi",
+ "tokio",
 ]
 
 [[package]]
 name = "noodles-vcf"
-version = "0.41.0"
+version = "0.42.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a0c31d3f5fd3bef22fcca702e2a85ab93f1c076a9e34cb94bc0c21874d2f4e02"
+checksum = "f3400ba59844268d1f3e842ca4dd999c08cd04180db1b413d689bb7ea92ece08"
 dependencies = [
+ "futures",
  "indexmap 2.0.2",
  "memchr",
  "noodles-bgzf 0.25.0",
@@ -2025,6 +2251,7 @@ dependencies = [
  "noodles-csi",
  "noodles-tabix",
  "percent-encoding",
+ "tokio",
 ]
 
 [[package]]
@@ -2077,6 +2304,16 @@ dependencies = [
  "libm",
 ]
 
+[[package]]
+name = "num_cpus"
+version = "1.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4161fcb6d602d4d2081af7c3a45852d875a03dd337a6bfdd6e06407b61342a43"
+dependencies = [
+ "hermit-abi",
+ "libc",
+]
+
 [[package]]
 name = "number_prefix"
 version = "0.4.0"
@@ -2113,6 +2350,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
 
+[[package]]
+name = "parking"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb813b8af86854136c6922af0598d719255ecb2179515e6e7730d468f05c9cae"
+
 [[package]]
 name = "parking_lot"
 version = "0.12.1"
@@ -2220,12 +2463,39 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
+[[package]]
+name = "piper"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "668d31b1c4eba19242f2088b2bf3316b82ca31082a8335764db4e083db7485d4"
+dependencies = [
+ "atomic-waker",
+ "fastrand 2.0.1",
+ "futures-io",
+]
+
 [[package]]
 name = "pkg-config"
 version = "0.3.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "26072860ba924cbfa98ea39c8c19b4dd6a4a25423dbdf219c1eca91aa0cf6964"
 
+[[package]]
+name = "polling"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b2d323e8ca7996b3e23126511a523f7e62924d93ecd5ae73b333815b0eb3dce"
+dependencies = [
+ "autocfg",
+ "bitflags 1.3.2",
+ "cfg-if",
+ "concurrent-queue",
+ "libc",
+ "log",
+ "pin-project-lite",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "portable-atomic"
 version = "1.4.3"
@@ -2664,6 +2934,20 @@ dependencies = [
  "windows-sys 0.45.0",
 ]
 
+[[package]]
+name = "rustix"
+version = "0.37.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "84f3f8f960ed3b5a59055428714943298bf3fa2d4a1d53135084e0544829d995"
+dependencies = [
+ "bitflags 1.3.2",
+ "errno",
+ "io-lifetimes",
+ "libc",
+ "linux-raw-sys 0.3.8",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "rustix"
 version = "0.38.20"
@@ -2890,6 +3174,16 @@ version = "1.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "942b4a808e05215192e39f4ab80813e599068285906cc91aa64f923db842bd5a"
 
+[[package]]
+name = "socket2"
+version = "0.4.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f7916fc008ca5542385b89a3d3ce689953c143e9304a9bf8beec1de48994c0d"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "socket2"
 version = "0.5.5"
@@ -3016,7 +3310,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cb94d2f3cc536af71caac6b6fcebf65860b347e7ce0cc9ebe8f70d3e521054ef"
 dependencies = [
  "cfg-if",
- "fastrand",
+ "fastrand 2.0.1",
  "redox_syscall 0.3.5",
  "rustix 0.38.20",
  "windows-sys 0.48.0",
@@ -3121,13 +3415,26 @@ dependencies = [
  "bytes",
  "libc",
  "mio",
+ "num_cpus",
  "parking_lot",
  "pin-project-lite",
  "signal-hook-registry",
- "socket2",
+ "socket2 0.5.5",
+ "tokio-macros",
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "tokio-macros"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "630bdcf245f78637c13ec01ffae6187cca34625e8c63150d424b59e55af2675e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.38",
+]
+
 [[package]]
 name = "tokio-postgres"
 version = "0.7.10"
@@ -3148,7 +3455,7 @@ dependencies = [
  "postgres-protocol",
  "postgres-types",
  "rand",
- "socket2",
+ "socket2 0.5.5",
  "tokio",
  "tokio-util",
  "whoami",
@@ -3305,6 +3612,12 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
 
+[[package]]
+name = "value-bag"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a72e1902dde2bd6441347de2b70b7f5d59bf157c6c62f0c44572607a1d55bbe"
+
 [[package]]
 name = "vcpkg"
 version = "0.2.15"
@@ -3326,6 +3639,12 @@ version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "waker-fn"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3c4517f54858c779bbcbf228f4fca63d121bf85fbecb2dc578cdf4a39395690"
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
@@ -3357,6 +3676,18 @@ dependencies = [
  "wasm-bindgen-shared",
 ]
 
+[[package]]
+name = "wasm-bindgen-futures"
+version = "0.4.37"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c02dbc21516f9f1f04f187958890d7e6026df8d16540b7ad9492bc34a67cea03"
+dependencies = [
+ "cfg-if",
+ "js-sys",
+ "wasm-bindgen",
+ "web-sys",
+]
+
 [[package]]
 name = "wasm-bindgen-macro"
 version = "0.2.87"
diff --git a/Cargo.toml b/Cargo.toml
index 7478b4ee..091bd2d7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,6 +29,7 @@ path = "src/main.rs"
 actix-web = "4.4"
 annonars = "0.24"
 anyhow = "1.0"
+async-compression = { version = "0.4", features = ["tokio", "gzip"] }
 bgzip = "0.3"
 bio = "1.3"
 biocommons-bioutils = "0.1.4"
@@ -41,6 +42,7 @@ csv = "1.3"
 derivative = "2.2"
 env_logger = "0.10"
 flate2 = "1.0"
+futures = "0.3.28"
 hgvs = "0.12"
 indexmap = { version = "2.0", features = ["serde"] }
 indicatif = "0.17"
@@ -52,8 +54,8 @@ noodles-bgzf = "0.25"
 noodles-core = "0.12"
 noodles-csi = "0.25"
 noodles-fasta = "0.30"
-noodles-tabix = "0.30"
-noodles-vcf = "0.41"
+noodles-tabix = "0.31"
+noodles-vcf = { version = "0.42", features = ["async"] }
 parse-display = "0.8"
 procfs = "0.15"
 prost = "0.12"
@@ -69,6 +71,7 @@ serde_with = { version = "3.3", features = ["indexmap_2"] }
 strum = { version = "0.25", features = ["derive"] }
 tempfile = "3"
 thousands = "0.2"
+tokio = { version = "1.33", features = ["full"] }
 tracing = { version = "0.1", features = ["log"] }
 tracing-subscriber = "0.3"
 uuid = { version = "1.4", features = ["fast-rng", "serde"] }
@@ -78,6 +81,7 @@ zstd = "0.13"
 prost-build = "0.12"
 
 [dev-dependencies]
+async-std = { version = "1.12", features = ["attributes"] }
 csv = "1.3"
 insta = { version = "1.34", features = ["yaml"] }
 pretty_assertions = "1.4"
diff --git a/src/annotate/seqvars/csq.rs b/src/annotate/seqvars/csq.rs
index fc8b7a58..84d3c4df 100644
--- a/src/annotate/seqvars/csq.rs
+++ b/src/annotate/seqvars/csq.rs
@@ -738,13 +738,9 @@ mod test {
         #[case] spdi: &str,
         #[case] expected_dist: i32,
     ) -> Result<(), anyhow::Error> {
-        crate::common::set_snapshot_suffix!("{}", spdi.replace(":", "-"));
+        crate::common::set_snapshot_suffix!("{}", spdi.replace(':', "-"));
 
-        let spdi = spdi
-            .split(":")
-            .into_iter()
-            .map(|s| s.to_string())
-            .collect::<Vec<_>>();
+        let spdi = spdi.split(':').map(|s| s.to_string()).collect::<Vec<_>>();
 
         let tx_path = "tests/data/annotate/db/grch37/txs.bin.zst";
         let tx_db = load_tx_db(tx_path)?;
diff --git a/src/annotate/strucvars/mod.rs b/src/annotate/strucvars/mod.rs
index 9fab7d6e..6d9b1d0b 100644
--- a/src/annotate/strucvars/mod.rs
+++ b/src/annotate/strucvars/mod.rs
@@ -10,7 +10,8 @@ use std::path::Path;
 use std::str::FromStr;
 use std::{fs::File, io::BufWriter};
 
-use crate::common::{open_read_maybe_gz, GenomeRelease};
+use crate::common::noodles::{open_vcf_reader, AsyncVcfReader};
+use crate::common::GenomeRelease;
 use crate::ped::PedigreeByName;
 use annonars::common::cli::CANONICAL;
 use annonars::freqs::cli::import::reading::guess_assembly;
@@ -20,6 +21,7 @@ use chrono::Utc;
 use clap::{Args as ClapArgs, Parser};
 use flate2::write::GzEncoder;
 use flate2::Compression;
+use futures::TryStreamExt;
 use noodles_bgzf::Writer as BgzfWriter;
 use noodles_vcf::reader::Builder as VariantReaderBuilder;
 use noodles_vcf::record::alternate_bases::Allele;
@@ -1626,13 +1628,14 @@ impl SvCaller {
 }
 
 /// Guess the `SvCaller` from the VCF file at the given path.
-pub fn guess_sv_caller(reader: Box<dyn std::io::BufRead>) -> Result<SvCaller, anyhow::Error> {
-    let mut reader = noodles_vcf::reader::Builder.build_from_reader(reader)?;
-    let header = reader.read_header()?;
+pub async fn guess_sv_caller(reader: &mut AsyncVcfReader) -> Result<SvCaller, anyhow::Error> {
+    let header = reader.read_header().await?;
     let mut records = reader.records(&header);
     let record = records
-        .next()
-        .ok_or(anyhow::anyhow!("No records found"))??;
+        .try_next()
+        .await
+        .map_err(|e| anyhow::anyhow!("Problem reading VCF records: {}", e))?
+        .ok_or(anyhow::anyhow!("No records found"))?;
 
     for caller in SvCaller::iter() {
         if caller.caller_compatible(&header) {
@@ -2854,7 +2857,7 @@ pub fn read_and_cluster_for_contig(
 /// * `args`: The command line arguments.
 /// * `pedigree`: The pedigree of case.
 /// * `header`: The input VCF header.
-fn run_with_writer(
+async fn run_with_writer(
     writer: &mut dyn AnnotatedVcfWriter,
     args: &Args,
     pedigree: &PedigreeByName,
@@ -2886,8 +2889,8 @@ fn run_with_writer(
     tracing::info!("Input VCF files to temporary files...");
     for path_input in args.path_input_vcf.iter() {
         tracing::debug!("processing VCF file {}", path_input);
-        let reader = open_read_maybe_gz(path_input)?;
-        let sv_caller = guess_sv_caller(reader)?;
+        let mut reader = open_vcf_reader(path_input).await?;
+        let sv_caller = guess_sv_caller(&mut reader).await?;
         tracing::debug!("guessed caller/version to be {:?}", &sv_caller);
 
         let mut reader = noodles_vcf::reader::Builder.build_from_path(path_input)?;
@@ -2942,7 +2945,7 @@ fn run_with_writer(
 }
 
 /// Main entry point for `annotate strucvars` sub command.
-pub fn run(_common: &crate::common::Args, args: &Args) -> Result<(), anyhow::Error> {
+pub async fn run(_common: &crate::common::Args, args: &Args) -> Result<(), anyhow::Error> {
     tracing::info!("config = {:#?}", &args);
     // Load the pedigree.
     tracing::info!("Loading pedigree...");
@@ -2979,13 +2982,13 @@ pub fn run(_common: &crate::common::Args, args: &Args) -> Result<(), anyhow::Err
             );
             writer.set_assembly(assembly);
             writer.set_pedigree(&pedigree);
-            run_with_writer(&mut writer, &args, &pedigree, &header)?;
+            run_with_writer(&mut writer, &args, &pedigree, &header).await?;
         } else {
             let mut writer =
                 noodles_vcf::Writer::new(File::create(path_output_vcf).map(BufWriter::new)?);
             writer.set_assembly(assembly);
             writer.set_pedigree(&pedigree);
-            run_with_writer(&mut writer, &args, &pedigree, &header)?;
+            run_with_writer(&mut writer, &args, &pedigree, &header).await?;
         }
     } else {
         let path_output_tsv = args
@@ -2997,7 +3000,7 @@ pub fn run(_common: &crate::common::Args, args: &Args) -> Result<(), anyhow::Err
         writer.set_assembly(assembly);
         writer.set_pedigree(&pedigree);
 
-        run_with_writer(&mut writer, &args, &pedigree, &header)?;
+        run_with_writer(&mut writer, &args, &pedigree, &header).await?;
     }
 
     Ok(())
@@ -3150,7 +3153,7 @@ mod test {
                 VarFishStrucvarTsvRecord,
             },
         },
-        common::{open_read_maybe_gz, GenomeRelease},
+        common::{noodles::open_vcf_reader, GenomeRelease},
         ped::{Disease, Individual, PedigreeByName, Sex},
     };
 
@@ -3375,8 +3378,8 @@ mod test {
         )
     }
 
-    #[test]
-    fn vcf_to_jsonl_with_detection() -> Result<(), anyhow::Error> {
+    #[tokio::test]
+    async fn vcf_to_jsonl_with_detection() -> Result<(), anyhow::Error> {
         let keys = &[
             "delly2",
             "dragen-cnv",
@@ -3391,7 +3394,8 @@ mod test {
             let path_expected_txt = format!("tests/data/annotate/strucvars/{}-min.out.jsonl", key);
             let samples = vcf_samples(&path_input_vcf)?;
             let pedigree: PedigreeByName = sample_ped(&samples);
-            let sv_caller = guess_sv_caller(open_read_maybe_gz(&path_input_vcf)?)?;
+            let mut reader = open_vcf_reader(&path_input_vcf).await?;
+            let sv_caller = guess_sv_caller(&mut reader).await?;
             let converter = build_vcf_record_converter(&sv_caller, &samples);
 
             run_test_vcf_to_jsonl(
@@ -3405,71 +3409,65 @@ mod test {
         Ok(())
     }
 
-    #[test]
-    fn guess_sv_caller_delly() -> Result<(), anyhow::Error> {
-        let sv_caller = guess_sv_caller(open_read_maybe_gz(
-            "tests/data/annotate/strucvars/delly2-min.vcf",
-        )?)?;
+    #[tokio::test]
+    async fn guess_sv_caller_delly() -> Result<(), anyhow::Error> {
+        let mut reader = open_vcf_reader("tests/data/annotate/strucvars/delly2-min.vcf").await?;
+        let sv_caller = guess_sv_caller(&mut reader).await?;
         insta::assert_debug_snapshot!(sv_caller);
 
         Ok(())
     }
 
-    #[test]
-    fn guess_sv_caller_dragen_sv() -> Result<(), anyhow::Error> {
-        let sv_caller = guess_sv_caller(open_read_maybe_gz(
-            "tests/data/annotate/strucvars/dragen-sv-min.vcf",
-        )?)?;
+    #[tokio::test]
+    async fn guess_sv_caller_dragen_sv() -> Result<(), anyhow::Error> {
+        let mut reader = open_vcf_reader("tests/data/annotate/strucvars/dragen-sv-min.vcf").await?;
+        let sv_caller = guess_sv_caller(&mut reader).await?;
         insta::assert_debug_snapshot!(sv_caller);
 
         Ok(())
     }
 
-    #[test]
-    fn guess_sv_caller_dragen_cnv() -> Result<(), anyhow::Error> {
-        let sv_caller = guess_sv_caller(open_read_maybe_gz(
-            "tests/data/annotate/strucvars/dragen-cnv-min.vcf",
-        )?)?;
+    #[tokio::test]
+    async fn guess_sv_caller_dragen_cnv() -> Result<(), anyhow::Error> {
+        let mut reader =
+            open_vcf_reader("tests/data/annotate/strucvars/dragen-cnv-min.vcf").await?;
+        let sv_caller = guess_sv_caller(&mut reader).await?;
         insta::assert_debug_snapshot!(sv_caller);
 
         Ok(())
     }
 
-    #[test]
-    fn guess_sv_caller_gcnv() -> Result<(), anyhow::Error> {
-        let sv_caller = guess_sv_caller(open_read_maybe_gz(
-            "tests/data/annotate/strucvars/gcnv-min.vcf",
-        )?)?;
+    #[tokio::test]
+    async fn guess_sv_caller_gcnv() -> Result<(), anyhow::Error> {
+        let mut reader = open_vcf_reader("tests/data/annotate/strucvars/gcnv-min.vcf").await?;
+        let sv_caller = guess_sv_caller(&mut reader).await?;
         insta::assert_debug_snapshot!(sv_caller);
 
         Ok(())
     }
 
-    #[test]
-    fn guess_sv_caller_manta() -> Result<(), anyhow::Error> {
-        let sv_caller = guess_sv_caller(open_read_maybe_gz(
-            "tests/data/annotate/strucvars/manta-min.vcf",
-        )?)?;
+    #[tokio::test]
+    async fn guess_sv_caller_manta() -> Result<(), anyhow::Error> {
+        let mut reader = open_vcf_reader("tests/data/annotate/strucvars/manta-min.vcf").await?;
+        let sv_caller = guess_sv_caller(&mut reader).await?;
         insta::assert_debug_snapshot!(sv_caller);
 
         Ok(())
     }
 
-    #[test]
-    fn guess_sv_caller_melt() -> Result<(), anyhow::Error> {
-        let sv_caller = guess_sv_caller(open_read_maybe_gz(
-            "tests/data/annotate/strucvars/melt-min.vcf",
-        )?)?;
+    #[tokio::test]
+    async fn guess_sv_caller_melt() -> Result<(), anyhow::Error> {
+        let mut reader = open_vcf_reader("tests/data/annotate/strucvars/melt-min.vcf").await?;
+        let sv_caller = guess_sv_caller(&mut reader).await?;
         insta::assert_debug_snapshot!(sv_caller);
 
         Ok(())
     }
 
-    #[test]
-    fn guess_sv_caller_popdel() -> Result<(), anyhow::Error> {
-        let sv_caller = guess_sv_caller(open_read_maybe_gz(
-            "tests/data/annotate/strucvars/popdel-min.vcf",
-        )?)?;
+    #[tokio::test]
+    async fn guess_sv_caller_popdel() -> Result<(), anyhow::Error> {
+        let mut reader = open_vcf_reader("tests/data/annotate/strucvars/popdel-min.vcf").await?;
+        let sv_caller = guess_sv_caller(&mut reader).await?;
         insta::assert_debug_snapshot!(sv_caller);
 
         Ok(())
@@ -3814,7 +3812,8 @@ mod test {
     #[rstest]
     #[case(true)]
     #[case(false)]
-    fn test_with_maelstrom_reader(#[case] is_tsv: bool) -> Result<(), anyhow::Error> {
+    #[tokio::test]
+    async fn test_with_maelstrom_reader(#[case] is_tsv: bool) -> Result<(), anyhow::Error> {
         let temp = TempDir::default();
 
         let args_common = crate::common::Args {
@@ -3853,7 +3852,7 @@ mod test {
             rng_seed: Some(42),
         };
 
-        run(&args_common, &args)?;
+        run(&args_common, &args).await?;
 
         let expected = std::fs::read_to_string(format!(
             "tests/data/annotate/strucvars/maelstrom/delly2-min-with-maelstrom{}",
diff --git a/src/common/io/mod.rs b/src/common/io/mod.rs
new file mode 100644
index 00000000..3e064acb
--- /dev/null
+++ b/src/common/io/mod.rs
@@ -0,0 +1,4 @@
+//! Common, IO-related code.
+
+pub mod std;
+pub mod tokio;
diff --git a/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.bgz.snap b/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.bgz.snap
new file mode 100644
index 00000000..4c5fc901
--- /dev/null
+++ b/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.bgz.snap
@@ -0,0 +1,3005 @@
+---
+source: src/common/io/std.rs
+expression: "String::from_utf8(buf)?"
+---
+1
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diff --git a/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.gz.snap b/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.gz.snap
new file mode 100644
index 00000000..4c5fc901
--- /dev/null
+++ b/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.gz.snap
@@ -0,0 +1,3005 @@
+---
+source: src/common/io/std.rs
+expression: "String::from_utf8(buf)?"
+---
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diff --git a/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.snap b/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.snap
new file mode 100644
index 00000000..4c5fc901
--- /dev/null
+++ b/src/common/io/snapshots/mehari__common__io__std__test__open_read_maybe_gz@14kb.txt.snap
@@ -0,0 +1,3005 @@
+---
+source: src/common/io/std.rs
+expression: "String::from_utf8(buf)?"
+---
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diff --git a/src/common/io/snapshots/mehari__common__io__std__test__open_write_maybe_gz@false.snap b/src/common/io/snapshots/mehari__common__io__std__test__open_write_maybe_gz@false.snap
new file mode 100644
index 00000000..5a708147
--- /dev/null
+++ b/src/common/io/snapshots/mehari__common__io__std__test__open_write_maybe_gz@false.snap
@@ -0,0 +1,5 @@
+---
+source: src/common/io/std.rs
+expression: "format!(\"{:x?}\", & buf)"
+---
+[1f, 8b, 8, 0, 0, 0, 0, 0, 0, ff, 2, 0, 0, 0, ff, ff, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0]
diff --git a/src/common/io/snapshots/mehari__common__io__std__test__open_write_maybe_gz@true.snap b/src/common/io/snapshots/mehari__common__io__std__test__open_write_maybe_gz@true.snap
new file mode 100644
index 00000000..b6b85aba
--- /dev/null
+++ b/src/common/io/snapshots/mehari__common__io__std__test__open_write_maybe_gz@true.snap
@@ -0,0 +1,5 @@
+---
+source: src/common/io/std.rs
+expression: "format!(\"{:x?}\", & buf)"
+---
+[]
diff --git a/src/common/io/snapshots/mehari__common__io__std__test__read_lines.snap b/src/common/io/snapshots/mehari__common__io__std__test__read_lines.snap
new file mode 100644
index 00000000..31fc36f1
--- /dev/null
+++ b/src/common/io/snapshots/mehari__common__io__std__test__read_lines.snap
@@ -0,0 +1,8 @@
+---
+source: src/common/io/std.rs
+expression: lines
+---
+- one
+- two
+- three
+
diff --git a/src/common/io/std.rs b/src/common/io/std.rs
new file mode 100644
index 00000000..3051115f
--- /dev/null
+++ b/src/common/io/std.rs
@@ -0,0 +1,121 @@
+//! Common I/O code using sync I/O.
+
+use std::{
+    fs::File,
+    io::{BufRead, BufReader, BufWriter, Write},
+    path::Path,
+};
+
+use flate2::{bufread::MultiGzDecoder, write::GzEncoder, Compression};
+
+/// Returns whether the path looks like a gzip or bgzip file.
+pub fn is_gz<P>(path: P) -> bool
+where
+    P: AsRef<Path>,
+{
+    [Some(Some("gz")), Some(Some("bgz"))].contains(&path.as_ref().extension().map(|s| s.to_str()))
+}
+
+/// Transparently open a file with gzip decoder.
+pub fn open_read_maybe_gz<P>(path: P) -> Result<Box<dyn BufRead>, anyhow::Error>
+where
+    P: AsRef<Path>,
+{
+    if is_gz(path.as_ref()) {
+        tracing::trace!("Opening {:?} as gzip for reading", path.as_ref());
+        let file = File::open(path)?;
+        let bufreader = BufReader::new(file);
+        let decoder = MultiGzDecoder::new(bufreader);
+        Ok(Box::new(BufReader::new(decoder)))
+    } else {
+        tracing::trace!("Opening {:?} as plain text for reading", path.as_ref());
+        let file = File::open(path).map(BufReader::new)?;
+        Ok(Box::new(BufReader::new(file)))
+    }
+}
+
+/// Transparently open afile with gzip encoder.
+pub fn open_write_maybe_gz<P>(path: P) -> Result<Box<dyn Write>, anyhow::Error>
+where
+    P: AsRef<Path>,
+{
+    if path.as_ref().extension().map(|s| s.to_str()) == Some(Some("gz")) {
+        tracing::trace!("Opening {:?} as gzip for writing", path.as_ref());
+        let file = File::create(path)?;
+        let bufwriter = BufWriter::new(file);
+        let encoder = GzEncoder::new(bufwriter, Compression::default());
+        Ok(Box::new(encoder))
+    } else {
+        tracing::trace!("Opening {:?} as plain text for writing", path.as_ref());
+        let file = File::create(path)?;
+        Ok(Box::new(file))
+    }
+}
+
+// The output is wrapped in a Result to allow matching on errors
+// Returns an Iterator to the Reader of the lines of the file.
+pub fn read_lines<P: AsRef<Path>>(
+    filename: P,
+) -> std::io::Result<std::io::Lines<std::io::BufReader<File>>>
+where
+    P: AsRef<Path>,
+{
+    let file = File::open(filename)?;
+    Ok(std::io::BufReader::new(file).lines())
+}
+
+#[cfg(test)]
+mod test {
+    use std::io::Read;
+
+    #[rstest::rstest]
+    #[case(true)]
+    #[case(false)]
+    fn open_write_maybe_gz(#[case] is_gzip: bool) -> Result<(), anyhow::Error> {
+        crate::common::set_snapshot_suffix!("{:?}", is_gzip);
+
+        let filename = if is_gzip { "test.txt" } else { "test.txt.gz" };
+        let tmp_dir = temp_testdir::TempDir::default();
+
+        {
+            let mut f = super::open_write_maybe_gz(tmp_dir.join(filename))?;
+            f.flush()?;
+        }
+
+        let mut f = std::fs::File::open(tmp_dir.join(filename)).map(std::io::BufReader::new)?;
+        let mut buf = Vec::new();
+        f.read_to_end(&mut buf)?;
+
+        insta::assert_snapshot!(format!("{:x?}", &buf));
+
+        Ok(())
+    }
+
+    #[test]
+    fn read_lines() -> Result<(), anyhow::Error> {
+        let lines =
+            super::read_lines("tests/common/io/lines.txt")?.collect::<Result<Vec<_>, _>>()?;
+
+        insta::assert_yaml_snapshot!(lines);
+
+        Ok(())
+    }
+
+    #[rstest::rstest]
+    #[case("14kb.txt")]
+    #[case("14kb.txt.gz")]
+    #[case("14kb.txt.bgz")]
+    fn open_read_maybe_gz(#[case] path: &str) -> Result<(), anyhow::Error> {
+        crate::common::set_snapshot_suffix!("{}", path);
+        // Note that the 14kb.txt file contains about 14 KB of data so bgz will have multiple 4KB
+        // blocks.
+
+        let mut reader = super::open_read_maybe_gz(&format!("tests/common/io/{}", path))?;
+        let mut buf = Vec::new();
+        reader.read_to_end(&mut buf)?;
+
+        insta::assert_snapshot!(String::from_utf8(buf)?);
+
+        Ok(())
+    }
+}
diff --git a/src/common/io/tokio.rs b/src/common/io/tokio.rs
new file mode 100644
index 00000000..dcab6781
--- /dev/null
+++ b/src/common/io/tokio.rs
@@ -0,0 +1,36 @@
+//! Tokio-based async common I/O code.
+
+use async_compression::tokio::bufread::GzipDecoder;
+use std::path::Path;
+use std::pin::Pin;
+use tokio::fs::File;
+use tokio::io::{AsyncBufRead, BufReader};
+
+use crate::common::io::std::is_gz;
+
+/// Transparently open a file with gzip decoder.
+pub async fn open_read_maybe_gz<P>(path: P) -> Result<Pin<Box<dyn AsyncBufRead>>, anyhow::Error>
+where
+    P: AsRef<Path>,
+{
+    tracing::trace!(
+        "Opening {} as {} reading",
+        path.as_ref().display(),
+        "palin text"
+    );
+    let file = File::open(path.as_ref())
+        .await
+        .map_err(|e| anyhow::anyhow!("could not open file {}: {}", path.as_ref().display(), e))?;
+
+    if is_gz(path.as_ref()) {
+        let bufreader = BufReader::new(file);
+        let decoder = {
+            let mut decoder = GzipDecoder::new(bufreader);
+            decoder.multiple_members(true);
+            decoder
+        };
+        Ok(Box::pin(BufReader::new(decoder)))
+    } else {
+        Ok(Box::pin(BufReader::new(file)))
+    }
+}
diff --git a/src/common.rs b/src/common/mod.rs
similarity index 71%
rename from src/common.rs
rename to src/common/mod.rs
index 685452c7..69fc5d0a 100644
--- a/src/common.rs
+++ b/src/common/mod.rs
@@ -1,17 +1,14 @@
 //! Commonly used code.
 
-use std::{
-    fs::File,
-    io::{BufRead, BufReader},
-    ops::Range,
-    path::Path,
-};
+use std::ops::Range;
 
 use biocommons_bioutils::assemblies::Assembly;
 use byte_unit::Byte;
 use clap::Parser;
 use clap_verbosity_flag::{InfoLevel, Verbosity};
-use flate2::bufread::MultiGzDecoder;
+
+pub mod io;
+pub mod noodles;
 
 /// Commonly used command line arguments.
 #[derive(Parser, Debug)]
@@ -98,24 +95,6 @@ pub fn version() -> &'static str {
     return VERSION;
 }
 
-/// Transparently open a file with gzip decoder.
-pub fn open_read_maybe_gz<P>(path: P) -> Result<Box<dyn BufRead>, anyhow::Error>
-where
-    P: AsRef<Path>,
-{
-    if path.as_ref().extension().map(|s| s.to_str()) == Some(Some("gz")) {
-        tracing::trace!("Opening {:?} as gzip for reading", path.as_ref());
-        let file = File::open(path)?;
-        let bufreader = BufReader::new(file);
-        let decoder = MultiGzDecoder::new(bufreader);
-        Ok(Box::new(BufReader::new(decoder)))
-    } else {
-        tracing::trace!("Opening {:?} as plain text for reading", path.as_ref());
-        let file = File::open(path).map(BufReader::new)?;
-        Ok(Box::new(BufReader::new(file)))
-    }
-}
-
 /// Version information that is returned by the HTTP server.
 #[derive(serde::Serialize, serde::Deserialize, Default, Debug, Clone)]
 #[serde_with::skip_serializing_none]
@@ -149,26 +128,3 @@ macro_rules! set_snapshot_suffix {
 }
 
 pub use set_snapshot_suffix;
-
-#[cfg(test)]
-mod test {
-    #[rstest::rstest]
-    #[case(true)]
-    #[case(false)]
-    fn open_read_maybe_gz(#[case] is_gzip: bool) -> Result<(), anyhow::Error> {
-        crate::common::set_snapshot_suffix!("{:?}", is_gzip);
-
-        let mut f = super::open_read_maybe_gz(if is_gzip {
-            "tests/common/test.txt.gz"
-        } else {
-            "tests/common/test.txt"
-        })?;
-
-        let mut buf = String::new();
-        f.read_to_string(&mut buf)?;
-
-        insta::assert_snapshot!(&buf);
-
-        Ok(())
-    }
-}
diff --git a/src/common/noodles.rs b/src/common/noodles.rs
new file mode 100644
index 00000000..80dc7783
--- /dev/null
+++ b/src/common/noodles.rs
@@ -0,0 +1,31 @@
+//! Helper code for using noodles.
+
+use futures::future::join_all;
+use noodles_vcf as vcf;
+use tokio::io::AsyncBufRead;
+
+use super::io::tokio::open_read_maybe_gz;
+
+/// Alias for the async vcf reader that we will use.
+pub type AsyncVcfReader = vcf::AsyncReader<std::pin::Pin<Box<dyn AsyncBufRead>>>;
+
+/// Helper function that opens one VCF reader at the given path.
+pub async fn open_vcf_reader(path_in: &str) -> Result<AsyncVcfReader, anyhow::Error> {
+    Ok(vcf::AsyncReader::new(
+        open_read_maybe_gz(path_in)
+            .await
+            .map_err(|e| anyhow::anyhow!("could not build VCF reader: {}", e))?,
+    ))
+}
+
+/// Helper function that opens a list of paths as VCF readers.
+pub async fn open_vcf_readers(paths: &[String]) -> Result<Vec<AsyncVcfReader>, anyhow::Error> {
+    Ok(join_all(paths.iter().map(open_read_maybe_gz))
+        .await
+        .into_iter()
+        .collect::<Result<Vec<_>, _>>()
+        .map_err(|e| anyhow::anyhow!("could not build VCF reader: {}", e))?
+        .into_iter()
+        .map(vcf::AsyncReader::new)
+        .collect::<Vec<_>>())
+}
diff --git a/src/main.rs b/src/main.rs
index 09d92996..7262e2c9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -167,7 +167,8 @@ enum VerifyCommands {
     Seqvars(verify::seqvars::Args),
 }
 
-fn main() -> Result<(), anyhow::Error> {
+#[tokio::main]
+async fn main() -> Result<(), anyhow::Error> {
     let cli = Cli::parse();
 
     // Build a tracing subscriber according to the configuration in `cli.common`.
@@ -185,32 +186,31 @@ fn main() -> Result<(), anyhow::Error> {
         })
         .compact()
         .finish();
+    tracing::subscriber::set_global_default(collector)?;
 
     // Install collector and go into sub commands.
-    tracing::subscriber::with_default(collector, || {
-        tracing::info!("Mehari startup -- letting the dromedary off the leash...");
-
-        match &cli.command {
-            Commands::Db(db) => match &db.command {
-                DbCommands::Create(db_create) => match &db_create.command {
-                    DbCreateCommands::Txs(args) => db::create::txs::run(&cli.common, args)?,
-                },
-            },
-            Commands::Annotate(annotate) => match &annotate.command {
-                AnnotateCommands::Seqvars(args) => annotate::seqvars::run(&cli.common, args)?,
-                AnnotateCommands::Strucvars(args) => annotate::strucvars::run(&cli.common, args)?,
-            },
-            Commands::Verify(verify) => match &verify.command {
-                VerifyCommands::Seqvars(args) => verify::seqvars::run(&cli.common, args)?,
-            },
-            Commands::RunServer(args) => server::run(&cli.common, args)?,
-        }
+    tracing::info!("Mehari startup -- letting the dromedary off the leash...");
 
-        tracing::info!("... the dromedary is back in the stable.");
-        tracing::info!("All done. Have a nice day!");
-
-        Ok::<(), anyhow::Error>(())
-    })?;
+    match &cli.command {
+        Commands::Db(db) => match &db.command {
+            DbCommands::Create(db_create) => match &db_create.command {
+                DbCreateCommands::Txs(args) => db::create::txs::run(&cli.common, args)?,
+            },
+        },
+        Commands::Annotate(annotate) => match &annotate.command {
+            AnnotateCommands::Seqvars(args) => annotate::seqvars::run(&cli.common, args)?,
+            AnnotateCommands::Strucvars(args) => {
+                annotate::strucvars::run(&cli.common, args).await?
+            }
+        },
+        Commands::Verify(verify) => match &verify.command {
+            VerifyCommands::Seqvars(args) => verify::seqvars::run(&cli.common, args)?,
+        },
+        Commands::RunServer(args) => server::run(&cli.common, args)?,
+    }
+
+    tracing::info!("... the dromedary is back in the stable.");
+    tracing::info!("All done. Have a nice day!");
 
     Ok(())
 }
diff --git a/tests/common/io/14kb.txt b/tests/common/io/14kb.txt
new file mode 100644
index 00000000..1127304b
--- /dev/null
+++ b/tests/common/io/14kb.txt
@@ -0,0 +1,3000 @@
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diff --git a/tests/common/io/14kb.txt.bgz b/tests/common/io/14kb.txt.bgz
new file mode 120000
index 00000000..5debaa3e
--- /dev/null
+++ b/tests/common/io/14kb.txt.bgz
@@ -0,0 +1 @@
+14kb.txt.gz
\ No newline at end of file
diff --git a/tests/common/io/14kb.txt.gz b/tests/common/io/14kb.txt.gz
new file mode 100644
index 00000000..68c68967
Binary files /dev/null and b/tests/common/io/14kb.txt.gz differ
diff --git a/tests/common/io/bootstrap.sh b/tests/common/io/bootstrap.sh
new file mode 100644
index 00000000..e401ee7f
--- /dev/null
+++ b/tests/common/io/bootstrap.sh
@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+
+set -x
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+
+cd $SCRIPT_DIR
+
+rm -rf 14kb.txt 14kb.txt.gz 14kb.txt.bgz
+
+seq 3000 > 14kb.txt
+bgzip -c 14kb.txt >14kb.txt.gz
+ln -sr 14kb.txt.gz 14kb.txt.bgz
diff --git a/tests/common/io/lines.txt b/tests/common/io/lines.txt
new file mode 100644
index 00000000..4cb29ea3
--- /dev/null
+++ b/tests/common/io/lines.txt
@@ -0,0 +1,3 @@
+one
+two
+three
diff --git a/tests/common/test.txt b/tests/common/io/test.txt
similarity index 100%
rename from tests/common/test.txt
rename to tests/common/io/test.txt
diff --git a/tests/common/test.txt.gz b/tests/common/io/test.txt.gz
similarity index 100%
rename from tests/common/test.txt.gz
rename to tests/common/io/test.txt.gz