diff --git a/builder/build.go b/builder/build.go
index 714a331a39..923af2dc40 100644
--- a/builder/build.go
+++ b/builder/build.go
@@ -189,7 +189,7 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 		defer unlock()
 		libcDependencies = append(libcDependencies, libcJob)
 		libcDependencies = append(libcDependencies, makeMinGWExtraLibs(tmpdir, config.GOARCH())...)
-	case "":
+	case "", "none":
 		// no library specified, so nothing to do
 	default:
 		return BuildResult{}, fmt.Errorf("unknown libc: %s", config.Target.Libc)
diff --git a/compileopts/config.go b/compileopts/config.go
index 1920d2b9cb..05ed0aff42 100644
--- a/compileopts/config.go
+++ b/compileopts/config.go
@@ -437,7 +437,7 @@ func (c *Config) LibcCFlags() []string {
 			)
 		}
 		return cflags
-	case "":
+	case "", "none":
 		// No libc specified, nothing to add.
 		return nil
 	default:
diff --git a/goenv/goenv.go b/goenv/goenv.go
index fe4c8bf63e..cecb5a85dd 100644
--- a/goenv/goenv.go
+++ b/goenv/goenv.go
@@ -151,6 +151,8 @@ func Get(name string) string {
 			panic("could not find cache dir: " + err.Error())
 		}
 		return filepath.Join(dir, "tinygo")
+	case "CGO_CFLAGS":
+		return os.Getenv("CGO_CFLAGS")
 	case "CGO_ENABLED":
 		// Always enable CGo. It is required by a number of targets, including
 		// macOS and the rp2040.
diff --git a/loader/loader.go b/loader/loader.go
index 1ca1b6679d..c323fb5193 100644
--- a/loader/loader.go
+++ b/loader/loader.go
@@ -485,6 +485,7 @@ func (p *Package) parseFiles() ([]*ast.File, error) {
 		var initialCFlags []string
 		initialCFlags = append(initialCFlags, p.program.config.CFlags(true)...)
 		initialCFlags = append(initialCFlags, "-I"+p.Dir)
+		initialCFlags = append(initialCFlags, goenv.Get("CGO_CFLAGS"))
 		generated, headerCode, cflags, ldflags, accessedFiles, errs := cgo.Process(files, p.program.workingDir, p.ImportPath, p.program.fset, initialCFlags, p.program.config.GOOS())
 		p.CFlags = append(initialCFlags, cflags...)
 		p.CGoHeaders = headerCode
diff --git a/src/crypto/rand/rand_espidf.go b/src/crypto/rand/rand_espidf.go
new file mode 100644
index 0000000000..bf18b4aa16
--- /dev/null
+++ b/src/crypto/rand/rand_espidf.go
@@ -0,0 +1,22 @@
+//go:build espidf
+
+package rand
+
+import "unsafe"
+
+func init() {
+	Reader = &reader{}
+}
+
+type reader struct{}
+
+//export esp_fill_random
+func esp_fill_random(buf unsafe.Pointer, len uintptr)
+
+func (r *reader) Read(b []byte) (n int, err error) {
+	if len(b) == 0 {
+		return
+	}
+	esp_fill_random(unsafe.Pointer(&b[0]), uintptr(len(b)))
+	return len(b), nil
+}
diff --git a/src/device/esp/esp32s3-stack.S b/src/device/esp/esp32s3-stack.S
new file mode 100644
index 0000000000..a4f54a5f9d
--- /dev/null
+++ b/src/device/esp/esp32s3-stack.S
@@ -0,0 +1,52 @@
+// -----------------------------------------------------------------------
+// tinygo_scanCurrentStack — Spill all Xtensa register windows to the
+// stack, then call tinygo_scanstack(sp) so the conservative GC can
+// discover live heap pointers that are currently in physical registers.
+//
+// On RISC-V / ARM the equivalent function pushes callee-saved registers
+// before the call.  On Xtensa windowed ABI the same effect is achieved
+// by forcing hardware window-overflow for every occupied pane: each
+// overflow saves the four registers in that pane to the stack frame
+// pointed to by the pane's a1 (sp).  After all panes are flushed, a
+// scan from the current sp to stackTop covers every live value.
+// -----------------------------------------------------------------------
+.section .text.tinygo_scanstack
+
+.global tinygo_scanCurrentStack
+tinygo_scanCurrentStack:
+    entry a1, 48
+
+    // Disable interrupts while flushing register windows.
+    rsr   a4, PS
+    s32i  a4, a1, 0         // save PS for later restore
+    rsil  a4, 3             // XCHAL_EXCM_LEVEL
+
+    // Flush all register windows using recursive call4.
+    // For NAREG=64 (16 panes), 15 recursive levels cover all panes
+    // except the current one (which is kept active).
+    movi a6, 15
+    call4 .Lscan_spill
+
+    // Restore interrupts.
+    l32i  a4, a1, 0
+    wsr.ps a4
+    rsync
+
+    // Pass current sp to tinygo_scanstack.
+    // call4 maps caller's a5→callee's a1 (stack ptr for callee's entry)
+    // and caller's a6→callee's a2 (first argument = sp).
+    mov  a5, a1             // callee's a1 = valid stack pointer
+    mov  a6, a1             // callee's a2 = sp argument
+    call4 tinygo_scanstack
+
+    retw
+
+    .balign 4
+.Lscan_spill:
+    entry a1, 16
+    beqz  a2, .Lscan_spill_done
+    addi  a2, a2, -1
+    mov   a6, a2
+    call4 .Lscan_spill
+.Lscan_spill_done:
+    retw
diff --git a/src/device/esp/esp32s3.S b/src/device/esp/esp32s3.S
index 6566e3f342..5572a3d484 100644
--- a/src/device/esp/esp32s3.S
+++ b/src/device/esp/esp32s3.S
@@ -342,56 +342,3 @@ call_start_cpu0:
 
     // If main returns, loop forever.
 1:  j 1b
-
-// -----------------------------------------------------------------------
-// tinygo_scanCurrentStack — Spill all Xtensa register windows to the
-// stack, then call tinygo_scanstack(sp) so the conservative GC can
-// discover live heap pointers that are currently in physical registers.
-//
-// On RISC-V / ARM the equivalent function pushes callee-saved registers
-// before the call.  On Xtensa windowed ABI the same effect is achieved
-// by forcing hardware window-overflow for every occupied pane: each
-// overflow saves the four registers in that pane to the stack frame
-// pointed to by the pane's a1 (sp).  After all panes are flushed, a
-// scan from the current sp to stackTop covers every live value.
-// -----------------------------------------------------------------------
-.section .text.tinygo_scanCurrentStack
-
-.global tinygo_scanCurrentStack
-tinygo_scanCurrentStack:
-    entry a1, 48
-
-    // Disable interrupts while flushing register windows.
-    rsr   a4, PS
-    s32i  a4, a1, 0         // save PS for later restore
-    rsil  a4, 3             // XCHAL_EXCM_LEVEL
-
-    // Flush all register windows using recursive call4.
-    // For NAREG=64 (16 panes), 15 recursive levels cover all panes
-    // except the current one (which is kept active).
-    movi a6, 15
-    call4 .Lscan_spill
-
-    // Restore interrupts.
-    l32i  a4, a1, 0
-    wsr.ps a4
-    rsync
-
-    // Pass current sp to tinygo_scanstack.
-    // call4 maps caller's a5→callee's a1 (stack ptr for callee's entry)
-    // and caller's a6→callee's a2 (first argument = sp).
-    mov  a5, a1             // callee's a1 = valid stack pointer
-    mov  a6, a1             // callee's a2 = sp argument
-    call4 tinygo_scanstack
-
-    retw
-
-    .balign 4
-.Lscan_spill:
-    entry a1, 16
-    beqz  a2, .Lscan_spill_done
-    addi  a2, a2, -1
-    mov   a6, a2
-    call4 .Lscan_spill
-.Lscan_spill_done:
-    retw
diff --git a/src/runtime/atomics_critical.go b/src/runtime/atomics_critical.go
index 74ce321f10..33173c7901 100644
--- a/src/runtime/atomics_critical.go
+++ b/src/runtime/atomics_critical.go
@@ -1,4 +1,4 @@
-//go:build baremetal && !tinygo.wasm
+//go:build baremetal && !tinygo.wasm && !espidf
 
 // Automatically generated file. DO NOT EDIT.
 // This file implements standins for non-native atomics using critical sections.
diff --git a/src/runtime/baremetal.go b/src/runtime/baremetal.go
index 9915f191b2..04b931e664 100644
--- a/src/runtime/baremetal.go
+++ b/src/runtime/baremetal.go
@@ -1,4 +1,4 @@
-//go:build baremetal
+//go:build baremetal && !espidf
 
 package runtime
 
diff --git a/src/runtime/interrupt/interrupt_none.go b/src/runtime/interrupt/interrupt_none.go
index ea8bdb68c6..b8e009e142 100644
--- a/src/runtime/interrupt/interrupt_none.go
+++ b/src/runtime/interrupt/interrupt_none.go
@@ -1,4 +1,4 @@
-//go:build !baremetal || tkey
+//go:build !baremetal || tkey || espidf
 
 package interrupt
 
diff --git a/src/runtime/interrupt/interrupt_tinygoriscv.go b/src/runtime/interrupt/interrupt_tinygoriscv.go
index 558e67150c..4e897eaa73 100644
--- a/src/runtime/interrupt/interrupt_tinygoriscv.go
+++ b/src/runtime/interrupt/interrupt_tinygoriscv.go
@@ -1,4 +1,4 @@
-//go:build tinygo.riscv && !tkey
+//go:build tinygo.riscv && !tkey && !espidf
 
 package interrupt
 
diff --git a/src/runtime/interrupt/interrupt_xtensa.go b/src/runtime/interrupt/interrupt_xtensa.go
index bbe70afb6f..67206d139d 100644
--- a/src/runtime/interrupt/interrupt_xtensa.go
+++ b/src/runtime/interrupt/interrupt_xtensa.go
@@ -1,4 +1,4 @@
-//go:build xtensa && !esp32s3
+//go:build xtensa && !esp32s3 && !espidf
 
 package interrupt
 
diff --git a/src/runtime/rand_norng.go b/src/runtime/rand_norng.go
index b9ab475c76..53de54f328 100644
--- a/src/runtime/rand_norng.go
+++ b/src/runtime/rand_norng.go
@@ -1,4 +1,4 @@
-//go:build baremetal && !(nrf || (stm32 && !(stm32f103 || stm32l0x1 || stm32g0)) || (sam && atsamd51) || (sam && atsame5x) || esp32c3 || esp32s3 || tkey || (tinygo.riscv32 && virt) || rp2040 || rp2350)
+//go:build baremetal && !(nrf || (stm32 && !(stm32f103 || stm32l0x1 || stm32g0)) || (sam && atsamd51) || (sam && atsame5x) || esp32c3 || esp32s3 || espidf || tkey || (tinygo.riscv32 && virt) || rp2040 || rp2350)
 
 package runtime
 
diff --git a/src/runtime/runtime_espidf.go b/src/runtime/runtime_espidf.go
new file mode 100644
index 0000000000..63f188d032
--- /dev/null
+++ b/src/runtime/runtime_espidf.go
@@ -0,0 +1,128 @@
+//go:build espidf
+
+package runtime
+
+import "unsafe"
+
+var (
+	heapStart    uintptr
+	heapEnd      uintptr
+	globalsStart uintptr
+	globalsEnd   uintptr
+	stackTop     uintptr
+)
+
+// Allows C consumers of the library to set the GC variables.
+//
+//export tinygo_init
+func tinygo_init(heap, heapSize, glob, globEnd, stack uintptr) {
+	heapStart, heapEnd = heap, heap+heapSize
+	globalsStart, globalsEnd = glob, globEnd
+	stackTop = stack
+	initRand()
+	initHeap()
+	initAll()
+}
+
+func growHeap() bool {
+	return false
+}
+
+//export abort
+func abort()
+
+//export exit
+func exit(code int)
+
+//export putchar
+func libc_putchar(c byte)
+
+func putchar(c byte) {
+	libc_putchar(c)
+}
+
+//export getchar
+func libc_getchar() byte
+
+func getchar() byte {
+	return libc_getchar()
+}
+
+func buffered() int {
+	return 0
+}
+
+const (
+	clock_REALTIME  = 1
+	clock_MONOTONIC = 4
+)
+
+type timespec struct {
+	tv_sec  int64
+	tv_nsec int32
+}
+
+//export clock_gettime
+func clock_gettime(clock int32, ts *timespec)
+
+func getTime(clock int32) uint64 {
+	var ts timespec
+	clock_gettime(clock, &ts)
+	return uint64(ts.tv_sec)*1e9 + uint64(ts.tv_nsec)
+}
+
+func monotime() uint64 {
+	return getTime(clock_MONOTONIC)
+}
+
+func ticks() timeUnit {
+	return timeUnit(monotime())
+}
+
+func ticksToNanoseconds(ticks timeUnit) int64 {
+	return int64(ticks)
+}
+
+func nanosecondsToTicks(ns int64) timeUnit {
+	return timeUnit(ns)
+}
+
+//export usleep
+func usleep(usec uint) int
+
+func sleepTicks(d timeUnit) {
+	usleep(uint(d / 1e3))
+}
+
+const baremetal = true
+
+//go:linkname now time.now
+func now() (sec int64, nsec int32, mono int64) {
+	var ts timespec
+	clock_gettime(clock_REALTIME, &ts)
+	sec = ts.tv_sec
+	nsec = ts.tv_nsec
+	mono = nanotime()
+	return
+}
+
+// Picolibc is not configured to define its own errno value, instead it calls
+// __errno_location.
+// TODO: a global works well enough for now (same as errno on Linux with
+// -scheduler=tasks), but this should ideally be a thread-local variable stored
+// in task.Task.
+// Especially when we add multicore support for microcontrollers.
+var errno int32
+
+//export __errno_location
+func libc_errno_location() *int32 {
+	return &errno
+}
+
+//export esp_fill_random
+func esp_fill_random(buf unsafe.Pointer, len uintptr)
+
+func hardwareRand() (n uint64, ok bool) {
+	esp_fill_random(unsafe.Pointer(&n), 8)
+	return n, true
+}
diff --git a/targets/esp32c3-idf.json b/targets/esp32c3-idf.json
new file mode 100644
index 0000000000..540e9842e3
--- /dev/null
+++ b/targets/esp32c3-idf.json
@@ -0,0 +1,15 @@
+{
+	"inherits": ["riscv32"],
+	"features": "+32bit,+c,+m,+zmmul,-a,-b,-d,-e,-experimental-sdext,-experimental-sdtrig,-experimental-smctr,-experimental-ssctr,-experimental-svukte,-experimental-xqcia,-experimental-xqciac,-experimental-xqcicli,-experimental-xqcicm,-experimental-xqcics,-experimental-xqcicsr,-experimental-xqciint,-experimental-xqcilo,-experimental-xqcilsm,-experimental-xqcisls,-experimental-zalasr,-experimental-zicfilp,-experimental-zicfiss,-experimental-zvbc32e,-experimental-zvkgs,-f,-h,-relax,-sha,-shcounterenw,-shgatpa,-shtvala,-shvsatpa,-shvstvala,-shvstvecd,-smaia,-smcdeleg,-smcsrind,-smdbltrp,-smepmp,-smmpm,-smnpm,-smrnmi,-smstateen,-ssaia,-ssccfg,-ssccptr,-sscofpmf,-sscounterenw,-sscsrind,-ssdbltrp,-ssnpm,-sspm,-ssqosid,-ssstateen,-ssstrict,-sstc,-sstvala,-sstvecd,-ssu64xl,-supm,-svade,-svadu,-svbare,-svinval,-svnapot,-svpbmt,-svvptc,-v,-xcvalu,-xcvbi,-xcvbitmanip,-xcvelw,-xcvmac,-xcvmem,-xcvsimd,-xesppie,-xmipscmove,-xmipslsp,-xsfcease,-xsfvcp,-xsfvfnrclipxfqf,-xsfvfwmaccqqq,-xsfvqmaccdod,-xsfvqmaccqoq,-xsifivecdiscarddlone,-xsifivecflushdlone,-xtheadba,-xtheadbb,-xtheadbs,-xtheadcmo,-xtheadcondmov,-xtheadfmemidx,-xtheadmac,-xtheadmemidx,-xtheadmempair,-xtheadsync,-xtheadvdot,-xventanacondops,-xwchc,-za128rs,-za64rs,-zaamo,-zabha,-zacas,-zalrsc,-zama16b,-zawrs,-zba,-zbb,-zbc,-zbkb,-zbkc,-zbkx,-zbs,-zca,-zcb,-zcd,-zce,-zcf,-zcmop,-zcmp,-zcmt,-zdinx,-zfa,-zfbfmin,-zfh,-zfhmin,-zfinx,-zhinx,-zhinxmin,-zic64b,-zicbom,-zicbop,-zicboz,-ziccamoa,-ziccif,-zicclsm,-ziccrse,-zicntr,-zicond,-zicsr,-zifencei,-zihintntl,-zihintpause,-zihpm,-zimop,-zk,-zkn,-zknd,-zkne,-zknh,-zkr,-zks,-zksed,-zksh,-zkt,-ztso,-zvbb,-zvbc,-zve32f,-zve32x,-zve64d,-zve64f,-zve64x,-zvfbfmin,-zvfbfwma,-zvfh,-zvfhmin,-zvkb,-zvkg,-zvkn,-zvknc,-zvkned,-zvkng,-zvknha,-zvknhb,-zvks,-zvksc,-zvksed,-zvksg,-zvksh,-zvkt,-zvl1024b,-zvl128b,-zvl16384b,-zvl2048b,-zvl256b,-zvl32768b,-zvl32b,-zvl4096b,-zvl512b,-zvl64b,-zvl65536b,-zvl8192b",
+	"build-tags": ["espidf", "esp"],
+	"scheduler": "none",
+	"rtlib": "none",
+	"libc": "none",
+	"cflags": [
+		"-march=rv32imc"
+	],
+	"ldflags": [
+		"-r",
+		"--no-gc-sections"
+	]
+}
diff --git a/targets/esp32s3-idf.json b/targets/esp32s3-idf.json
new file mode 100644
index 0000000000..3bf9dac8c1
--- /dev/null
+++ b/targets/esp32s3-idf.json
@@ -0,0 +1,14 @@
+{
+	"inherits": ["xtensa"],
+	"cpu": "esp32s3",
+	"features": "+atomctl,+bool,+clamps,+coprocessor,+debug,+density,+div32,+esp32s3,+exception,+fp,+highpriinterrupts,+interrupt,+loop,+mac16,+memctl,+minmax,+miscsr,+mul32,+mul32high,+nsa,+prid,+regprotect,+rvector,+s32c1i,+sext,+threadptr,+timerint,+windowed",
+	"build-tags": ["espidf", "esp"],
+	"linker": "ld.lld",
+	"ldflags": [
+		"-r",
+		"--no-gc-sections"
+	],
+	"extra-files": [
+		"src/device/esp/esp32s3-stack.S"
+	]
+}
diff --git a/targets/esp32s3.json b/targets/esp32s3.json
index ea6527d6d5..a1c3c28475 100644
--- a/targets/esp32s3.json
+++ b/targets/esp32s3.json
@@ -20,6 +20,7 @@
 	"linkerscript": "targets/esp32s3.ld",
 	"extra-files": [
 		"src/device/esp/esp32s3.S",
+		"src/device/esp/esp32s3-stack.S",
 		"targets/esp32s3-interrupts.S",
 		"src/internal/task/task_stack_esp32.S"
 	],
diff --git a/tools/gen-critical-atomics/gen-critical-atomics.go b/tools/gen-critical-atomics/gen-critical-atomics.go
index 98ceebb020..a8ce6f3819 100644
--- a/tools/gen-critical-atomics/gen-critical-atomics.go
+++ b/tools/gen-critical-atomics/gen-critical-atomics.go
@@ -17,7 +17,7 @@ var tmpl = template.Must(template.New("go").Funcs(template.FuncMap{
 		return v
 	},
 	"title": strings.Title,
-}).Parse(`//go:build baremetal && !tinygo.wasm
+}).Parse(`//go:build baremetal && !tinygo.wasm && !espidf
 
 // Automatically generated file. DO NOT EDIT.
 // This file implements standins for non-native atomics using critical sections.