diff --git a/rhp/v4/rhp.go b/rhp/v4/rhp.go
index 379ef03b..f5814278 100644
--- a/rhp/v4/rhp.go
+++ b/rhp/v4/rhp.go
@@ -3,7 +3,6 @@ package rhp
 import (
 	"bytes"
 	"encoding/hex"
-	"errors"
 	"fmt"
 	"io"
 	"time"
@@ -549,52 +548,6 @@ func MinRenterAllowance(hp HostPrices, duration uint64, collateral types.Currenc
 	return hp.StoragePrice.Mul64(duration).Mul(maxCollateralBytes).Mul64(9).Div64(10) // 10% buffer
 }
 
-// ValidateFormContractParams checks the given contract parameters for validity.
-func ValidateFormContractParams(hs HostSettings, tip types.ChainIndex, req RPCFormContractParams) error {
-	hp := hs.Prices
-	expirationHeight := req.ProofHeight + proofWindow
-	duration := expirationHeight - hp.TipHeight
-	minRenterAllowance := MinRenterAllowance(hp, duration, req.Collateral)
-
-	switch {
-	case expirationHeight <= hp.TipHeight: // must be validated against tip instead of prices
-		return errors.New("contract expiration height is in the past")
-	case req.Allowance.IsZero():
-		return errors.New("allowance is zero")
-	case req.Collateral.Cmp(hs.MaxCollateral) > 0:
-		return fmt.Errorf("collateral %v exceeds max collateral %v", req.Collateral, hs.MaxCollateral)
-	case duration > hs.MaxContractDuration:
-		return fmt.Errorf("contract duration %v exceeds max duration %v", duration, hs.MaxContractDuration)
-	case req.Allowance.Cmp(minRenterAllowance) < 0:
-		return fmt.Errorf("allowance %v is less than minimum %v for collateral", req.Allowance, minRenterAllowance)
-	default:
-		return nil
-	}
-}
-
-// ValidateRenewContractParams checks the given renew parameters for validity.
-func ValidateRenewContractParams(hs HostSettings, tip types.ChainIndex, req RPCRenewContractParams) error {
-	hp := hs.Prices
-	expirationHeight := req.ProofHeight + proofWindow
-	duration := expirationHeight - hp.TipHeight
-	minRenterAllowance := MinRenterAllowance(hp, duration, req.Collateral)
-
-	switch {
-	case expirationHeight <= tip.Height: // must be validated against tip instead of prices
-		return errors.New("contract expiration height is in the past")
-	case req.Allowance.IsZero():
-		return errors.New("allowance is zero")
-	case req.Collateral.Cmp(hs.MaxCollateral) > 0:
-		return fmt.Errorf("collateral %v exceeds max collateral %v", req.Collateral, hs.MaxCollateral)
-	case duration > hs.MaxContractDuration:
-		return fmt.Errorf("contract duration %v exceeds max duration %v", duration, hs.MaxContractDuration)
-	case req.Allowance.Cmp(minRenterAllowance) < 0:
-		return fmt.Errorf("allowance %v is less than minimum %v for collateral", req.Allowance, minRenterAllowance)
-	default:
-		return nil
-	}
-}
-
 // NewRenewal creates a contract renewal from an existing contract revision
 func NewRenewal(fc types.V2FileContract, prices HostPrices, rp RPCRenewContractParams) (renewal types.V2FileContractRenewal) {
 	expirationHeight := rp.ProofHeight + proofWindow
diff --git a/rhp/v4/validation.go b/rhp/v4/validation.go
new file mode 100644
index 00000000..a0b7d3e0
--- /dev/null
+++ b/rhp/v4/validation.go
@@ -0,0 +1,119 @@
+package rhp
+
+import (
+	"errors"
+	"fmt"
+
+	"go.sia.tech/core/types"
+)
+
+// Validate validates a read sector request.
+func (req *RPCReadSectorRequest) Validate() error {
+	switch {
+	case req.Length == 0:
+		return errors.New("length must be greater than 0")
+	case req.Offset+req.Length > SectorSize:
+		return errors.New("read request exceeds sector bounds")
+	case (req.Offset+req.Length)%LeafSize != 0:
+		return errors.New("read request must be segment aligned")
+	}
+	return nil
+}
+
+// Validate validates a write sector request.
+func (req *RPCWriteSectorRequest) Validate() error {
+	switch {
+	case req.Duration == 0:
+		return errors.New("duration must be greater than 0")
+	case len(req.Sector) == 0:
+		return errors.New("sector must not be empty")
+	case len(req.Sector)%LeafSize != 0:
+		return errors.New("sector must be segment aligned")
+	}
+	return nil
+}
+
+// Validate validates a sector roots request. Signatures are not validated.
+func (req *RPCSectorRootsRequest) Validate(fc types.V2FileContract) error {
+	contractSectors := fc.Filesize / SectorSize
+
+	switch {
+	case req.Length == 0:
+		return errors.New("length must be greater than 0")
+	case req.Length+req.Offset > contractSectors:
+		return fmt.Errorf("read request range exceeds contract sectors: %d > %d", req.Length+req.Offset, contractSectors)
+	}
+	return nil
+}
+
+// Validate validates a form contract request. Prices are not validated
+func (req *RPCFormContractRequest) Validate(hs HostSettings, tip types.ChainIndex) error {
+	// validate the request fields
+	switch {
+	case req.MinerFee.IsZero():
+		return errors.New("miner fee must be greater than 0")
+	case req.Basis != (types.ChainIndex{}):
+		return errors.New("basis must be set")
+	case len(req.RenterInputs) == 0:
+		return errors.New("renter inputs must not be empty")
+	}
+
+	// validate the contract fields
+	hp := hs.Prices
+	expirationHeight := req.Contract.ProofHeight + proofWindow
+	duration := expirationHeight - hp.TipHeight
+	// calculate the minimum allowance required for the contract based on the
+	// host's locked collateral and the contract duration
+	minRenterAllowance := MinRenterAllowance(hp, duration, req.Contract.Collateral)
+
+	switch {
+	case expirationHeight <= tip.Height: // must be validated against tip instead of prices
+		return errors.New("contract expiration height is in the past")
+	case req.Contract.Allowance.IsZero():
+		return errors.New("allowance is zero")
+	case req.Contract.Collateral.Cmp(hs.MaxCollateral) > 0:
+		return fmt.Errorf("collateral %v exceeds max collateral %v", req.Contract.Collateral, hs.MaxCollateral)
+	case duration > hs.MaxContractDuration:
+		return fmt.Errorf("contract duration %v exceeds max duration %v", duration, hs.MaxContractDuration)
+	case req.Contract.Allowance.Cmp(minRenterAllowance) < 0:
+		return fmt.Errorf("allowance %v is less than minimum %v for collateral", req.Contract.Allowance, minRenterAllowance)
+	default:
+		return nil
+	}
+}
+
+// Validate validates a renew contract request. Prices are not validated
+func (req *RPCRenewContractRequest) Validate(hs HostSettings, tip types.ChainIndex) error {
+	// validate the request fields
+	switch {
+	case req.MinerFee.IsZero():
+		return errors.New("miner fee must be greater than 0")
+	case req.Basis != (types.ChainIndex{}):
+		return errors.New("basis must be set")
+	case len(req.RenterInputs) == 0:
+		return errors.New("renter inputs must not be empty")
+	}
+
+	// validate the contract fields
+	hp := hs.Prices
+	expirationHeight := req.Renewal.ProofHeight + proofWindow
+	duration := expirationHeight - hp.TipHeight
+	// calculate the minimum allowance required for the contract based on the
+	// host's locked collateral and the contract duration
+	minRenterAllowance := MinRenterAllowance(hp, duration, req.Renewal.Collateral)
+
+	switch {
+	case expirationHeight <= tip.Height: // must be validated against tip instead of prices
+		return errors.New("contract expiration height is in the past")
+	case req.Renewal.Allowance.IsZero():
+		return errors.New("allowance is zero")
+	case req.Renewal.Collateral.Cmp(hs.MaxCollateral) > 0:
+		return fmt.Errorf("collateral %v exceeds max collateral %v", req.Renewal.Collateral, hs.MaxCollateral)
+	case duration > hs.MaxContractDuration:
+		return fmt.Errorf("contract duration %v exceeds max duration %v", duration, hs.MaxContractDuration)
+	case req.Renewal.Allowance.Cmp(minRenterAllowance) < 0:
+		return fmt.Errorf("allowance %v is less than minimum %v for collateral", req.Renewal.Allowance, minRenterAllowance)
+	default:
+		return nil
+	}
+}