diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 000000000..e2e5fa90e
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,11 @@
+[env]
+# In unoptimised builds tokio tends to use a lot of stack space when
+# creating some complicated futures, tokio has an open issue for this:
+# https://github.com/tokio-rs/tokio/issues/2055.  Some of our tests
+# manage to not fit in the default 2MiB stack anymore due to this, so
+# while the issue is not resolved we want to work around this.
+# Because compiling optimised builds takes a very long time we prefer
+# to avoid that.  Setting this environment variable ensures that when
+# invoking `cargo test` threads are allowed to have a large enough
+# stack size without needing to use an optimised build.
+RUST_MIN_STACK = "8388608"
diff --git a/.github/workflows/jsonrpc.yml b/.github/workflows/jsonrpc.yml
index 082ddb569..5b1781a46 100644
--- a/.github/workflows/jsonrpc.yml
+++ b/.github/workflows/jsonrpc.yml
@@ -8,6 +8,7 @@ on:
 
 env:
   CARGO_TERM_COLOR: always
+  RUST_MIN_STACK: "8388608"
 
 jobs:
   build_and_test:
diff --git a/Cargo.toml b/Cargo.toml
index 871ad9dbb..dd7f55fbe 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,6 +11,9 @@ debug = 0
 panic = 'abort'
 opt-level = 1
 
+[profile.test]
+opt-level = 0
+
 [profile.release]
 lto = true
 panic = 'abort'
diff --git a/deltachat-jsonrpc/typescript/test/test_base.ts b/deltachat-jsonrpc/typescript/test/test_base.ts
index 71c79b235..3d6da6faa 100644
--- a/deltachat-jsonrpc/typescript/test/test_base.ts
+++ b/deltachat-jsonrpc/typescript/test/test_base.ts
@@ -30,7 +30,8 @@ export async function startServer(port: number = RPC_SERVER_PORT): Promise<RpcSe
     cwd: tmpDir,
     env: {
       RUST_LOG: process.env.RUST_LOG || "info",
-      DC_PORT: '' + port
+      DC_PORT: '' + port,
+      RUST_MIN_STACK: "8388608"
     },
   });
   let shouldClose = false;
diff --git a/python/tox.ini b/python/tox.ini
index 74cc1c554..eaa444646 100644
--- a/python/tox.ini
+++ b/python/tox.ini
@@ -10,6 +10,9 @@ envlist =
 commands = 
     pytest -n6 --extra-info --reruns 2 --reruns-delay 5 -v -rsXx --ignored --strict-tls {posargs: tests examples}
     pip wheel . -w {toxworkdir}/wheelhouse --no-deps
+setenv =
+# Avoid stack overflow when Rust core is built without optimizations.
+    RUST_MIN_STACK=8388608
 passenv = 
     DCC_RS_DEV
     DCC_RS_TARGET