diff --git a/loglist/helpers.go b/loglist/helpers.go
new file mode 100644
index 0000000..8f1a0f6
--- /dev/null
+++ b/loglist/helpers.go
@@ -0,0 +1,37 @@
+// Copyright (C) 2020 Opsmate, Inc.
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License, v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+// This software is distributed WITHOUT A WARRANTY OF ANY KIND.
+// See the Mozilla Public License for details.
+
+package loglist
+
+import (
+	"encoding/base64"
+	"time"
+)
+
+func (list *List) AllLogs() []*Log {
+	logs := []*Log{}
+	for operator := range list.Operators {
+		for log := range list.Operators[operator].Logs {
+			logs = append(logs, &list.Operators[operator].Logs[log])
+		}
+	}
+	return logs
+}
+
+func (log *Log) LogIDString() string {
+	return base64.StdEncoding.EncodeToString(log.LogID)
+}
+
+func (log *Log) AcceptsExpiration(expiration time.Time) bool {
+	return log.TemporalInterval == nil || withinInterval(expiration, log.TemporalInterval.StartInclusive, log.TemporalInterval.EndExclusive)
+}
+
+func withinInterval(expiration, startInclusive, endExclusive time.Time) bool {
+	return !expiration.Before(startInclusive) && expiration.Before(endExclusive)
+}
diff --git a/loglist/load.go b/loglist/load.go
new file mode 100644
index 0000000..75b59dc
--- /dev/null
+++ b/loglist/load.go
@@ -0,0 +1,58 @@
+// Copyright (C) 2020 Opsmate, Inc.
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License, v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+// This software is distributed WITHOUT A WARRANTY OF ANY KIND.
+// See the Mozilla Public License for details.
+
+package loglist
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"io/ioutil"
+	"strings"
+)
+
+func Load(urlOrFile string) (*List, error) {
+	if strings.HasPrefix(urlOrFile, "https://") {
+		return Fetch(urlOrFile)
+	} else {
+		return ReadFile(urlOrFile)
+	}
+}
+
+func Fetch(url string) (*List, error) {
+	response, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	content, err := ioutil.ReadAll(response.Body)
+	response.Body.Close()
+	if err != nil {
+		return nil, err
+	}
+	if response.StatusCode != 200 {
+		return nil, fmt.Errorf("%s: %s", url, response.Status)
+	}
+	return unmarshal(content)
+}
+
+func ReadFile(filename string) (*List, error) {
+	content, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	return unmarshal(content)
+}
+
+func unmarshal(jsonBytes []byte) (*List, error) {
+	list := new(List)
+	if err := json.Unmarshal(jsonBytes, list); err != nil {
+		return nil, err
+	}
+	return list, nil
+}
diff --git a/loglist/schema.go b/loglist/schema.go
new file mode 100644
index 0000000..aa128ab
--- /dev/null
+++ b/loglist/schema.go
@@ -0,0 +1,77 @@
+// Copyright (C) 2020 Opsmate, Inc.
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License, v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+// This software is distributed WITHOUT A WARRANTY OF ANY KIND.
+// See the Mozilla Public License for details.
+
+package loglist
+
+import (
+	"time"
+)
+
+type List struct {
+	Version   string     `json:"version"`
+	Operators []Operator `json:"operators"`
+}
+
+type Operator struct {
+	Name  string   `json:"name"`
+	Email []string `json:"email"`
+	Logs  []Log    `json:"logs"`
+}
+
+type Log struct {
+	Key              []byte  `json:"key"`
+	LogID            []byte  `json:"log_id"`
+	MMD              int     `json:"mmd"`
+	URL              string  `json:"url"`
+	Description      string  `json:"description"`
+	State            State   `json:"state"`
+	DNS              string  `json:"dns"`
+	LogType          LogType `json:"log_type"`
+	TemporalInterval *struct {
+		StartInclusive time.Time `json:"start_inclusive"`
+		EndExclusive   time.Time `json:"end_exclusive"`
+	} `json:"temporal_interval"`
+}
+
+type State struct {
+	Pending *struct {
+		Timestamp time.Time `json:"timestamp"`
+	} `json:"pending"`
+
+	Qualified *struct {
+		Timestamp time.Time `json:"timestamp"`
+	} `json:"qualified"`
+
+	Usable *struct {
+		Timestamp time.Time `json:"timestamp"`
+	} `json:"usable"`
+
+	Readonly *struct {
+		Timestamp     time.Time `json:"timestamp"`
+		FinalTreeHead struct {
+			TreeSize       int64  `json:"tree_size"`
+			SHA256RootHash []byte `json:"sha256_root_hash"`
+		} `json:"final_tree_head"`
+	} `json:"readonly"`
+
+	Retired *struct {
+		Timestamp time.Time `json:"timestamp"`
+	} `json:"retired"`
+
+	Rejected *struct {
+		Timestamp time.Time `json:"timestamp"`
+	} `json:"rejected"`
+}
+
+type LogType string
+
+const (
+	LogTypeProd = "prod"
+	LogTypeTest = "test"
+)
diff --git a/loglist/validate.go b/loglist/validate.go
new file mode 100644
index 0000000..f03d2e9
--- /dev/null
+++ b/loglist/validate.go
@@ -0,0 +1,42 @@
+// Copyright (C) 2020 Opsmate, Inc.
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License, v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+// This software is distributed WITHOUT A WARRANTY OF ANY KIND.
+// See the Mozilla Public License for details.
+
+package loglist
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"fmt"
+)
+
+func (list *List) Validate() error {
+	for i := range list.Operators {
+		if err := list.Operators[i].Validate(); err != nil {
+			return fmt.Errorf("problem with %dth operator (%s): %w", i, list.Operators[i].Name, err)
+		}
+	}
+	return nil
+}
+
+func (operator *Operator) Validate() error {
+	for i := range operator.Logs {
+		if err := operator.Logs[i].Validate(); err != nil {
+			return fmt.Errorf("problem with %dth log (%s): %w", i, operator.Logs[i].LogIDString(), err)
+		}
+	}
+	return nil
+}
+
+func (log *Log) Validate() error {
+	realLogID := sha256.Sum256(log.Key)
+	if !bytes.Equal(log.LogID, realLogID[:]) {
+		return fmt.Errorf("log ID does not match log key")
+	}
+	return nil
+}